Cassava Production and Utilization

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PLANT SCIENCE RESEARCH AND PRACTICES

HANDBOOK ON CASSAVA PRODUCTION, POTENTIAL USES AND RECENT ADVANCES

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PLANT SCIENCE RESEARCH AND PRACTICES

HANDBOOK ON CASSAVA PRODUCTION, POTENTIAL USES AND RECENT ADVANCES

CLARISSA KLEIN EDITOR

New York


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NOTICE TO THE READER The Publisher has taken reasonable care in the preparation of this book, but makes no expressed or implied warranty of any kind and assumes no responsibility for any errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of information contained in this book. The Publisher shall not be liable for any special, consequential, or exemplary damages resulting, in whole or in part, from the readers’ use of, or reliance upon, this material. Any parts of this book based on government reports are so indicated and copyright is claimed for those parts to the extent applicable to compilations of such works. Independent verification should be sought for any data, advice or recommendations contained in this book. In addition, no responsibility is assumed by the publisher for any injury and/or damage to persons or property arising from any methods, products, instructions, ideas or otherwise contained in this publication. This publication is designed to provide accurate and authoritative information with regard to the subject matter covered herein. It is sold with the clear understanding that the Publisher is not engaged in rendering legal or any other professional services. If legal or any other expert assistance is required, the services of a competent person should be sought. FROM A DECLARATION OF PARTICIPANTS JOINTLY ADOPTED BY A COMMITTEE OF THE AMERICAN BAR ASSOCIATION AND A COMMITTEE OF PUBLISHERS. Additional color graphics may be available in the e-book version of this book.

Library of Congress Cataloging-in-Publication Data Names: Klein, Clarissa, editor. Title: Handbook on cassava: production, potential uses and recent advances / editor: Clarissa Klein. Other titles: Plant science research and practices. Description: Hauppauge, New York: Nova Science Publishers, [2016] | Series: Plant science research and practices | Includes index. Identifiers: LCCN 2016044245 (print) | LCCN 2016045346 (ebook) | ISBN 9781536102918 (hardcover) | ISBN 9781536103076 Subjects: LCSH: Cassava. | Cassava--Utilization. | Cassava--Technological innovations. Classification: LCC SB211.C3 H36 2016 (print) | LCC SB211.C3 (ebook) | DDC 633.6/82--dc23 LC record available at https://lccn.loc.gov/2016044245

Published by Nova Science Publishers, Inc. † New York


CONTENTS Preface Chapter 1

Chapter 2

Chapter 3

Chapter 4

Chapter 5

vii Comparison of Cassava and Sugarcane Bagasse for Fuel Ethanol Production Yessica Chacón Pérez, Daissy Lorena Restrepo Serna and Carlos Ariel Cardona Alzate Cassava Production and Its Economic Potentials in Sub-Sahara Africa: A Review Emmanuel Ukaobasi Mbah

29

Cassava Production and Utilization in the Coastal, Eastern and Western Regions of Kenya C. M. Githunguri, M. Gatheru and S. M. Ragwa

41

Socio-Economic Determinants of Modern Technology Adoption and the Influence of Farm Size on Productivity and Profitability in Cassava Production: A Case Study from South-Eastern Nigeria Chidiebere Daniel Chima and Sanzidur Rahman Cassava Flour as an Alternative to Produce Gluten-Free Baked Goods and Pastas Elevina Pérez, Lilliam Sívoli, Davdmary Cueto and Liz Pérez

Chapter 6

Technological Aspects of Processing of Cassava Derivatives Elisa Cristina Andrade Neves, Daniela Andrade Neves, Kleidson Brito de Sousa Lobato, Gustavo Costa do Nascimento and Maria Teresa Pedrosa Silva Clerici

Chapter 7

Sustainable Management of Cassava Processing Waste for Promoting Rural Development Anselm P. Moshi and Ivo Achu Nges

Chapter 8

1

Wastewater from Cassava Processing as a Platform for MicroalgaeMediated Processes Tatiele C. do Nascimento, Erika C. Francisco, Leila Queiroz Zepka and Eduardo Jacob-Lopes


55

87 105

129

149

vi

Contents

Chapter 9

Cassava Wastewater as Substrate in Biotechnological Processes Cristiano José de Andrade, Ana Paula Resende Simiqueli, Fabiola Aliaga de Lima, Juliana Bueno da Silva, Lidiane Maria de Andrade and Ana Elizabeth Cavalcante Fai

Chapter 10

Technical, Cost and Allocative Efficiency of Processing Cassava into Gari in Delta State, Nigeria Brodrick O. Awerije and Sanzidur Rahman

201

Status of Cassava Processing and Challenges in the Coastal, Eastern and Western Regions of Kenya C. M. Githunguri, M. Gatheru and S. M. Ragwa

217

Chapter 11

Chapter 12

Cassava Waste: A Potential Biotechnology Resource Aniekpeno I. Elijah

Chapter 13

Potential Uses of Cassava Products and Its Future Challenging Opportunities Reddy T. Ranjeth Kumar, Kim Hyun-Joong and Park Ji-Won

Chapter 14

Utilization of Modified Cassava Flour and Its By-Products Setiyo Gunawan, Zikrina Istighfarah, Hakun Wirawasista Aparamarta, Firdaus Syarifah and Ira Dwitasari

Chapter 15

Recent Advances in the Development of Biodegradable Films and Foams from Cassava Starch Giordana Suárez and Tomy J. Gutiérrez

Chapter 16

Cassava Cultivation, Processing and Potential Uses in Ghana Richard Bayitse, Ferdinand Tornyie and Anne-Belinda Bjerre

Chapter 17

Potential Uses of Cassava Bagasse for Bioenergy Generation by Pyrolysis and Copyrolysis with a Lignocellulosic Waste Luciano I. Gurevich Messina, Pablo R. Bonelli and Ana L. Cukierman

Chapter 18

Chapter 19

Trend in the Trade of Cassava Products in the Coastal, Eastern and Western Regions of Kenya C. M. Githunguri, M. Gatheru and S. M. Ragwa Wild Relatives of Cassava: Conservation and Use Márcio Lacerda Lopes Martins, Carlos Alberto da Silva Ledo, Paulo Cezar Lemos de Carvalho, André Márcio Amorim and Dreid Cerqueira Silveira da Silva

Index

171

231

251 271

297 313

335

357 373

407


PREFACE Cassava produces about 10 times more carbohydrates than most cereals per unit area, and are ideal for production in marginal and drought prone areas. Cassava, which originated from tropical South America, is a perennial woody shrub with an edible root, which today is grown in tropical and subtropical regions of the world where it provides energy food and serves as a veritable source of food and income for over a billion people. This handbook provides new research on the production, consumption and potential uses of cassava. Chapter 1 - During the last years, biofuels from different feedstocks have been studied and scaled up to industry to provide energy needing mainly for transport. Raw materials with high sugar content are mostly used in the production of biofuels as ethanol, butanol, hydrogen, etc. In the last years in tropical countries as Colombia, the ethanol production from starch and lignocellulosic biomass has been studied as a new alternative. Then, raw materials as cassava and sugarcane bagasse are presented as good options but more research is needed to understand the real advantages of these feedstocks. The amount of fermentable sugars obtained from the biomass is a decisive factor in the global yield of ethanol production. In this sense, different technological schemes can be proposed in the pretreatment step of the process followed by enzymatic hydrolysis to get the sugars. Starch-rich raw materials only require a milling and cooking as pretreatment. On the other hand, the pretreatment stage in some type of lignocellulosic materials must consider the reduction of particle size and specific technologies as dilute acid or alkaline methods. This chapter shows an analysis of ethanol production from cassava and sugarcane bagasse taking into account the availability, type and different pretreatment technologies to be applied to the raw material. Additionally, a techno-economic and environmental assessment is performed, in order to compare the proposed processes. Chapter 2 - Cassava (Manihot esculenta Crantz), which originated from tropical America and today a dietary staple to most people living in Sub-Sahara Africa is a perennial woody shrub with an edible root, which is rich in carbohydrates, calcium (50 mg 100-g), phosphorus (40 mg 100-g), vitamins B and C, as well as some essential minerals, while its tender leaves serve as a veritable source of lysine rich protein. The roots though poor in protein and other minerals, their nutrient compositions differ depending on the variety and age of the harvested crop, as well as soil conditions, climate, and other environmental factors under which the crop is grown. The stem of cassava is used as planting material and can serve as a standard substrate in mushroom production as well as fuel wood when dried. Cassava is characterized as one of the most drought tolerant crop that is capable of growing on marginal soils. The


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crop is rarely cultivated as a mono-crop because of its physiological growth habit and duration, which makes it to stand out as an excellent component crop in most intercropping systems. Hence, it is usually intercropped with most vegetables, yam, sweet potato, melon, maize, sorghum, millet, rice, groundnut, sesame, soybean, cowpea and other legumes, as well as plantation crops (such as oil palm, kola, rubber, cocoa, cashew and coffee) among other field crops grown in the tropical regions of the world. Roots of cassava may be due for harvesting between six months and three years (36 months) after planting. Apart from food, cassava root tubers are very versatile, hence its derivatives and qualitative starch are effectively used in a number of products such as foods, confectionery, sweeteners, paper, glues, textiles, plywood, biodegradable products, monosodium glutamate, and pharmaceuticals. Cassava chips and pellets are used in animal feed and alcohol production as well as ethanol and bio-diesels. Crop improvements associated with cassava is tailored on developing genotypes that can effectively correlate the end product with its utilization at the industrial level. The impact of research on cassava development ranging from biotecbreeding, genetics and selection to production, value-chain addition and utilization is immerse, hence, high quality improved cassava varieties which are disease- and pest-resistant, low in cyanide content, drought-resistant, early bulking, high starch content, high dry matter content, and high yielding are being cultivated by most farmers in the tropical regions today where cassava thrives. Annual world production of cassava (184 million tonnes) with Nigeria being the leading producer has continued to increase due to the development of improved varieties with high yield, excellent culinary qualities and resistance to pests and diseases among other invaluable properties. In this review therefore, scientific findings by a number of scholars on cassava are discussed with the aim of making the information a veritable tool for researchers in this field. Chapter 3 - Cassava is the second most important food root crop in Kenya. Despite its high production in the coastal and western regions, utilization is limited to human consumption. A situational analysis on cassava production was carried out to determine its current status in the western, coastal and eastern regions of Kenya. A sample of farmers was randomly selected from each region and interviewed using a structured questionnaire. Offfarm activities were undertaken by 37% in eastern and western and 32% in the coastal regions. Access to extension services was 50% in the coast, 65% in eastern and 88% in western regions. Relative to other food crops, 66.7% of respondents ranked cassava 2nd at the coastal region while 37.5% and 57% of respondents in eastern and western regions ranked it 5th and 1st, respectively. At the coastal, western and eastern regions, 92%, 67% and 65% of the respondents intercrop cassava with other crops, while 8%, 33% and 35% grow it as a sole crop, respectively. On adoption of improved cassava varieties, western region was leading with 77% followed by coast (30%) and eastern (13%). At the coast, 23% considered lack of market as the major constraint followed by pests and diseases (16%) and destruction by large mammalian pests (11%). In eastern, 15% reported drought as the major constraint followed by lack of market (13%) and pests and disease (42%). In western, the major constraints were large mammalian pests (12%), weeds (12%), lack of planting materials (8%) and insect pests (3%). At the coastal, eastern and western regions cassava was ranked second, fifth and first respectively relative to other food crops. The western region had more improved cassava varieties than the other regions. In the coastal region, the major constraint to production was lack of market while in the eastern region, the major constraint was drought and in western, the major constraints were wild animals and weeds. Cassava was utilized more as family food


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in western than in coastal and eastern regions. On processing of cassava and cassava based products, western region was leading followed by coastal and eastern region last. The western region was leading in the processing of dried cassava chips and composite flour. The coastal region was leading in the processing of fried cassava chips, crisps and pure flour. The eastern region was ranked least in processing with a few respondents making fried cassava chips and pure cassava flour. Chapter 4 - The chapter investigates the influence of socio-economic factors on the adoption of individual components of modern agricultural technology (i.e., HYV seeds and inorganic fertilizers) in cassava and also examines farm size–productivity and farm size– profitability relationships of cassava production in South-eastern Nigeria including a discussion of constraints in the cassava sector. The hypotheses of the study are that farmers selectively adopt components of modern agricultural technology depending on their socioeconomic circumstances and inverse farm size–technology adoption, size–productivity and size–profitability relationships exist in cassava production. The research is based on an indepth farm-survey of 344 farmers from two states (243 from Ebonyi and 101 from Anambra states) of South-eastern Nigeria. The results show that the sample respondents are dominated by small scale farmers (78.8% of total) owning land less than 1 ha. The average farm size is small estimated at 0.58 ha. The study clearly demonstrated that inverse farm size–technology adoption and farm size–productivity relationships exist in cassava production in this region of Nigeria but not inverse farm size–profitability relationship. The level of modern technology adoption is low and mixed and farmers selectively adopt components of technologies as expected and use far less than recommended dose of fertilizers. Only 20.35% of farmers adopted both HYV cassava stem and fertilizers as a package. The bivariate probit model diagnostic reveals that the decision to adopt modern technologies are significantly correlated, implying that univariate analysis of such decisions are biased, thereby, justifying use of the bivariate approach. The most dominant determinant of modern technology adoption in cassava is farming experience and remoteness of extension services depresses adoption. A host of constraints are affecting Nigerian agricultural sector, which includes lack of extension agents, credit facilities, farm inputs, irrigation, value addition and corruption, lack of support for ADP staff and ineffective government policies. Policy implications include investment in extension services, provision of credit facilities and other infrastructures (e.g., irrigation, ADP staff), training of small farmers in business skills, promotion of modern technology as a package as well as special projects (e.g., Cassava Plus project) in order to boost production of cassava at the farm-level in Nigeria. Chapter 5 - Celiac disease is an immune disorder in which people cannot tolerate gluten because it damages the inner lining of their small intestine and prevents it from absorbing nutrients. Gluten is a protein found in wheat, rye, and barley and occasionally in some other minor products. A lot of foods; such as, baked food and pastas are manufactured using flour from wheat, rye, barley and oats, in which the gluten defines its functional properties. People who want to manufacture products containing gluten, have been looking for alternatives to solve this problem and to insure gluten-free products for the celiac population. Because, the cassava flour does not have gluten; the foods made with this flour could be one of the solutions for the development of food for gluten-intolerant consumers. Some research has been done in regard to substitute the gluten totally in order to produce baked goods, and pastas, quite similar in its functional properties, to those produced by wheat flour. The research was initiated producing flour from the edible portion of the cassava roots. Native and


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modified flour from cassava roots were made using different treatments of heat, water concentration, as well as the use of salt, emulsifier, hydrocolloids or enzymes. All of the flour obtained were characterized in their chemical composition, physical, and functionality. The research suggests that is feasibility to use these types of flour in the production of numerous gluten-free baked goods, bread, and pastas, because they showed a wide spectrum of nutritional and functional properties which is causes by the effect of the additives and the treatments applied. Therefore, at a pilot phase, a second research experiment has started to produce pastas, and formulation of mix flour for cake, and pancakes, all of them gluten-free. The formulations and procedures that were implemented, as a function of the cassava flour, are discussed in this chapter. Chapter 6 - Cassava (Manihot esculenta Crantz) is a tuberous root grown in all regions of Brazil, mainly in the North region, and the state of Pará Pará is one of the largest producers. It is considered a high-energy food, rich in starch and fiber, but highly perishable, with moisture content of around 67.5%, used for direct human consumption or as raw material to produce cassava-derived products, by using the water activity principle for food conservation. Various products can be produced by artisanal or industrial processes, such as different types of cassava flour, cassava gums, fermented and native starch, tapioca flour, tucupi, among others. Flour is one of the main cassava products, and its use is widespread throughout the country as part of Brazilian eating habits, especially in the North and Northeast regions, consumed by rural, riverine, and urban populations of all social classes. However, the quality of cassava-derived products is very heterogeneous, often out of the standards established by Brazilian law, once they are produced by small producers following their decision-making processes. This chapter describes the technological differences in the manufacture of cassavaderived products, considering cassava varieties and processing stages, such as cassava fermentation before drying and drying process, as well as their effects on the physicochemical characteristics of the products, including moisture, pH, acidity, particle size, color of the products and gel, helping to spread the potential of cassava and enhancement of regional products. Chapter 7 - Cassava is the third-most important food source in the tropics after rice and maize. Cassava is the staple food for about half a billion people in the World. It is a tropical crop grown mainly in Africa, Asia, and South America. It can be cultivated on arid and semiarid land where other crops do not thrive. During the processing of cassava into chips, flour or starch, enormous amount of wastes are generated ca. 0.47 tons for each ton of fresh tubers processed. This waste consists of peels, wastewater and pulp that contain between 36 to 45% (w/w) of starch and from 55 to 64% (w/w) of lignocellulosic biomass. An innovative processing system is therefore essential to take into account the transformation of this waste into value added products. This will address both the environmental pollution and inefficient utilization of these resources. The starch and lignocellulosic cassava processing waste can be converted into renewable energy carriers such as biogas through anaerobic digestion (AD), bio-ethanol through fermentation and bio-hydrogen through dark fermentation. In the case of AD, the waste can be used directly as substrate while for fermentation; the waste must be pre-treated to release monomeric sugars, which are substrates for bio-ethanol and bio-hydrogen production. There is possibility of sequential fermentation for either bio-ethanol or bio-hydrogen and AD for biogas production thereby making use of all the fractions of the cassava waste.


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Generation of renewable energy from cassava waste could benefit rural populations where access to electricity is very poor. This would also reduce the dependence on firewood and charcoal that are known to provide almost 90 percent of domestic energy requirements. Such a development could help save trees, lower emissions that cause climate change and reduce the fumes from millions of tons of firewood that threaten human health, especially the health of women and children. Although deforestation and land degradation are well-known, the charcoal and firewood consumption that causes them is still on the rise. This chapter, therefore, explores the use of cassava waste for production of fuel energy with a focus for use as domestic cooking fuel. It also proposes an efficient approach to cassava processing to ensure efficient resource utilization in which every part of the tuber is converted to value added products mitigating environmental pollution and improving human health. Chapter 8 - Cassava is widely produced worldwide, and it is a suitable source of carbohydrates (roots), proteins and minerals (leaves). Because of perishability in fresh form, it is widely marketed in the form of gums and flour. Often, its roots have high amounts of cyanohydrin that emanates cyanide, which is highly toxic to human health. This toxic molecule is significantly present in the wastewater from the cassava processing. For this reason, the resulting wastewater, also known as manipueira, when dumped in the environment, causes huge damage to soil and to water sources. The environmental problem can be avoided by advances in industrial biotechnology, which offer potential opportunities for economic utilization of agro-industrial residues. Manipueira has high levels of organic matter and nutrients, which can serve as an ideal platform for bioprocesses mediated by microorganisms, especially microalgae, to obtain products with a high value, such as, carotenoids, phycobilins, polysaccharides, vitamins, fatty acids, and several natural bioactive compounds, which are applicable to foods, pharmaceutical products and bioenergy. This chapter describes the use of the wastewater from cassava processing as a platform for microalgae-mediated processes aiming to obtain bioproducts of commercial value. Divided into five parts, the chapter covers topics on cassava processing, the characteristics of waste from cassava, the impact of cassava waste on the environment, the potential industrial processes for wastewater conversion and the bioproducts from microalgae, summarizing a range of useful techno-economic opportunities to be applied on cassava processing plants. Chapter 9 - Progresses in biotechnological processes offer a vast array of possibilities for economic use of agro-industrial residues, such as cassava wastewater. Due to its chemical composition, cassava wastewater is an interesting substrate for microbial processes for the production of value-added bioproducts. Cassava wastewater comes from the manufacture of cassava (Manihot esculenta spp. esculenta) flour which has up to 90% of starch in its root (w/w) and is easily cultivable. The main producers of cassava in 2014 - Nigeria, Thailand, Indonesia and Brazil - were responsible for 48.61% of the total world production of 27.03 × 107 metric tons of the raw crop, which is mainly used as food and feed, but also as feedstock for biofuels and biochemicals. However, the industrial manufacturing of cassava roots generates a large amount of liquid (cassava wastewater – 2.5 liters/10 kg of cassava) and solid (bagasse) residues, in which are usually burned or disposed incorrectly. Cassava wastewater has a high content of nutrients including carbohydrates (9.6-37 g/L), protein (2.3 g/L), nitrogen (0.1-1.3 g/L) and minerals as phosphorous, potassium, calcium, magnesium, sulphur, iron, zinc, cooper, etc in pH value 5.5. Therefore, due to the plenty availability, non-market value, high content of nutrient and the continuous supply throughout the year (perennial


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crop), there is an interesting potential for the utilization of cassava wastewater as an alternative substrate in biotechnological processes, which would be in consonance with biorefinery approach. In this sense, during the past years, several biotechnological processes using cassava wastewater as substrate have been described, which are an alternative to reduce the production costs and the environmental impact. The various products which have been obtained from cassava waste water include biofuels (hydrogen, ethanol, butanol, methane), biosurfactants; organic acids (citric acid, lactic acid and succinic acid), volatile fatty acids (acetic, propionic, butyric and valeric acids), aromatic compounds, enzymes and prebiotics. Chapter 10 - The present study examines productivity, technical, cost and allocative efficiencies of processing cassava into gari by applying Data Envelopment Analysis (DEA) of 278 farmers/processors from three regions of Delta State, Nigeria. Results revealed that the mean levels of technical, cost and allocative efficiencies of gari processing is low estimated at 0.55, 0.35 and 0.64, respectively, implying that gari production can be increased substantially by reallocation of resources to optimal levels, given input and output prices. Inverse size– productivity and size–efficiency relationships exist in gari processing. In other words, marginal and small processors are significantly more productive and efficient relative to large processors. Availability of credit significantly improves technical and cost efficiencies. Extension contact significantly reduces efficiencies which is counterintuitive. Female processors are technically efficient relative to male processors while both perform equally well with respect to allocative and cost efficiencies in processing gari. Significant differences in efficiencies exist across regions as well. Processors located in Delta North and Delta South is relatively more efficient than processors located in Delta Central. A host of constraints affect gari processing which include lack of transportation, information, processing equipment and infrastructure and high cost of raw materials. Policy implications include investment in education targeted at small farmers/processors, improving agricultural credit services, processing equipments, infrastructure and transportation facilities and reforming extension services in order to make it effective in disseminating information regarding cassava processing. Chapter 11 - Whether cassava can be relied upon as a low cost staple food in urban centres and a source of steady real income for rural households will to a larger extent depend on how well it can be processed and presented to urban consumers in safe and attractive forms at competitive prices to those of cereals. A study was conducted in the coastal, eastern, central, and western regions of Kenya where only the major processors were visited and interviewed randomly using a structured questionnaire. At the coast, 62.5% of the processors were sole proprietors while 37.5% were in partnership. In the eastern region, 66.7% of the processors were sole proprietors while 33.3% were in partnership. In the western region, the only processor interviewed was a company based in Busia. At the coast, 75% of respondents had their own initial capital while in eastern 33% of respondents reported the same. Only 25% and 33% of respondents at the coast and eastern regions, respectively, had acquired their initial capital on credit. In western, the respondent had acquired initial capital through own resources and credit. In the study regions, all processors (100%) met their operating costs. In the coastal region (Mombasa), among the respondents interviewed, 50% made cassava crisps, 17% chapatti and 8% bhajia. In eastern region (Kibwezi), 50% made Nimix (composite flour) and 50% boiled cassava. In western region (Busia), 100% of respondents made composite flour (cassava mixed with other cereals). The major products reported were crisps, fried chips, composite flours (cassava mixed with cereals, legumes, leaves etc). Golden coloured crisps,


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fiber free cassava and sweet taste were preferred by consumers. Even though processors maintained high standards, none of the processors had their products patented. Processing of cassava products showed a rising trend which were marketed in supermarkets, direct consumers, retailers and wholesalers. Except for the eastern region, most processors could access raw materials throughout the year. Only a few processors in the coastal region had contractual arrangements with suppliers, whereas there was none in the other regions. Processing equipment were locally fabricated except in the eastern region where they were imported. The processors had reliable sources of power and water. The major constraints included market fluctuations, inadequate supply of cassava, city council regulations, competition from other related products like maize and sweetpotatoes, lack of credit facilities, market and capital, and processing equipment. Chapter 12 - Although cassava waste may pose serious environmental challenges if not properly disposed of, it could constitute important potential resource if properly harnessed especially by adopting modern biotechnology approach. In this study, plasmids extracted from bacterial isolates associated with cassava waste were explored, using molecular tools, in order to identify genes encoded on the plasmids as well as determine the industrial potentials of the genes borne on the plasmids. Bacterial species isolated from cassava peel (CP) and cassava wastewater (CW) from cassava processing centres in Abeokuta, Nigeria, were identified by aligning their 16S rRNA gene sequences with sequences in the GenBank. Plasmid DNA was extracted from the bacterial isolates, using the Pure Yield Plasmid Miniprep System (Promega, USA) and sequenced. The Open Reading Frame (ORF) Finder was used to identify ORFs on the plasmid DNAs. ORFs were translated and searched against publicly available archives [a non-redundant protein database of GenBank proteins, SWISSPROT and cluster of orthologous groups (COG)] using the BLAST-P algorithm. Putative genes borne on the plasmids, as well as their products, were deduced from the plasmid nucleotide sequences. Plasmids were found on 14 bacterial isolates. Eight of the isolates (Lactobacillus plantarum, L. brevis, Bacillus coagulans, B. circulans, B. licheniformis, B. pumilus, Enterococcus faecalis and Pediococcus pentosaceus) were from CP while 6 isolates (Lactobacillus fallax, L. fermentum, L. delbruckii, Weisella confusa, Bacillus subtilis and Leuconostoc mesenteroides) were from CW. The gene, tanLpl - encoding tannase was detected on Lactobacillus plantarum plasmid while the gene (bgl1E) which encodes betaglucosidase was found on Bacillus coagulans and Bacillus circulans plasmids. Other genes detected were hydroxynitrile lyase (HNL) gene on Bacillus licheniformis and Lactobacillus fermentum plasmids; poly-glutamic acid (PGA) synthesis regulator gene on Lactobacillus fermentum plasmid; glutamate synthase gene on Bacillus substilis plasmid; bacteriocin related genes on Lactobacillus fermentum, Lactobacillus fallax and Weisella confusa plasmids as well as some hypothetical proteins. These enzymes and accessory proteins are all well known for their importance in the food industry. Furthermore, the hypothetical proteins may turn out to be hitherto unknown enzymes for important metabolites or structural proteins. The plasmids could constitute an easy source of genes for mass production of the enzymes and their products. This study, therefore, shows that cassava waste has potentials as an important biotechnology resource, especially for the food industry. Chapter 13 - Cassava is the third largest source of food carbohydrates in the tropics after rice and maize. Cassava is a major staple food in the developing world, providing a basic diet for over half a billion people. Cassavas are multipurpose commercial products that have many potential uses, such as in bio-fuels, animal feed, medicines, bio-composite, food packaging


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and so on. Apart of from these uses, processed cassava serves as an industrial raw material for the production of adhesives, bakery products, dextrin, dextrose, glucose, lactose and sucrose. This chapter elucidates the uses of cassava products and its future challenging opportunities. Chapter 14 - Cassava is an important component in the diets of more than 800 million people around the world. It is kind of tropic and sub-tropic plant. It is able to grow in lessnutrition soil. In a dry land, cassava sheds its leaves to keep it damp and produces new leaves in the rainy season. Otherwise, cassava can not survive in cold weather but it can grow very well in the area with pH 4-8. Cassava needs at least 5 months in the summer for producing ripe cassava. The aim of this chapter is to discuss the proximate composition, production, application, and modification process of cassava roots as well as their future perspective. The typical important parameters for proximate composition of cassava are protein, lipids, fibre, starch, cyanide acid and ash contents. The carbon to nitrogen ratio (C/N ratio) of dried fresh cassava roots is also important parameter for microbial activities within fermentation process. The development of new utilization techniques of cassava roots has gained increasing importance in chemical, food, and pharmaceutical industries, due to their content of economically-valuable compounds, the necessity of environmental friendly process, global food and energy security. There are several different methodologies for enhancing detoxification and improving the quality of cassava flour, such as fermentation process (liquid, solid state, submerged, culture and spontaneous fermentations), different microorganisms (yeast, fungi and bacteria) and different additional nutrients (with and without nutrients). Moreover, lactid acid is produced as by-product during the fermentation. This is also interesting topic due to the potential application of lactic acid for the production of biodegradable polymers. Another, the analysis methods of the compounds in cassava roots are also a challenging work. Few analytical methods are available to provide a detailed and simpler analysis. It is of great interest if new utilization of cassava roots and analysis methods of the compounds in cassava roots are available to establish all products during the fermentation. Chapter 15 - Currently eco-friendly polymeric materials are made from different biopolymers. In this sense, special attention has brought the use of starch at industrial level, since can be processed as conventional polymers. In the same way, one of the starches most used for developing biodegradable films and foams for use as packing material has been cassava (Manihot esculenta) starch, due to its high production and performance, which makes it be a promising material for replacement of polymers obtained from the petrochemical industry. At regard, in this chapter will be reviewed and discussed recent advances related to the development of biodegradable films and foams made from cassava starch. Chapter 16 - This review highlights the traditional and improved methods of cassava production and processing in Ghana. It also explains the geographical distribution of cassava production and utilisation. Facts and figures from agricultural production in Ghana is used to analyse production trends as well as the contribution of cassava to Agricultural Gross Domestic Production. Most importantly, cassava is a staple food crop and accounts for about 152.9 kg per capita consumption. Making it one of the most processed crop into gari, fufu powder and kokonte to increase its shelf life. Additionally, it can be used as an industrial crop because of its high starch content. These process technologies have contributed to the reduction of post-harvest losses in cassava production in Ghana. The residue generated from cassava processing has a huge potential in biorefinery. The review also brings into focus current research works in cassava residue utilisation, reviewing technologies for converting


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xv

this valuable feedstock which is a mixture of cassava peels, trimmings and cuttings into sugar platform in a biorefinery for the production of major products such as ethanol, lactic acid and protein. Chapter 17 - Cassava (Manihot esculenta) bagasse is a fibrous by-product generated in the tuber processing. After washing and peeling, the cassava is grated and then water is added in order to extract the starch. The mixture is filtered such that a rich starch solution and a wet solid residue can be separated. This slurry, known as bagasse, comprises up to 20% of the weight of the processed cassava. In addition, as the extraction of starch from cassava is less efficient than those based on processing of potato or maize, the bagasse contains around 5070% of starch on a dry basis. As it has no important use, with the exception of animal feed, the bagasse is usually rejected to water courses increasing the environmental pollution. Therefore, several strategies are being studied to find useful applications for this by-product. Pyrolysis of the bagasse and copyrolysis, namely the thermal degradation of mixtures of the bagasse and lignocellulosic biomass in inert atmosphere, could be an appealing possibility to employ this waste in order to generate green energy and/or other value-added products. In particular, growing attention is paid to the liquid products arising from pyrolysis/copyrolysis, commonly known as bio-oils, since they show many of the advantages of liquid fuels, such as inexpensive storage and transportation, and high energy density. In this scenario, the processes of pyrolysis of cassava starch, the major constituent of dry cassava bagasse, and of copyrolyisis of the starch with peanut hulls, an abundant lignocellulosic residue, were studied by performing experiments in a fixed-bed reactor at different process temperatures (400ºC – 600ºC). The pyrolysis of the starch led to a higher maximum yield of bio-oils that took place at a lower temperature than the copyrolysis (57 wt% at 400ºC vs. 49 wt% at 500ºC). Physichochemical characterization of the three kinds of pyrolysis/copyrolysis products with emphasis on the bio-oils was carried out mainly by proximate and ultimate analyses, KarlFischer titration, Fourier-transformed infrared spectroscopy, N2 adsorption, scanning electronic microscopy, and gas chromatography (GC-TCD and GC-MS). While the pyrolysis of the starch resulted in bio-oils with less nitrogen content, the copyrolysis produced bio-oils with lower content of oxygen and higher carbon percent. Water content of the bio-oils increased with rising process temperatures and it was lower for the liquids resulting from the pyrolysis of the starch. Also, the bio-oils arising from the pyrolysis of the starch presented more sugar compounds and fewer phenols. Besides, the pyrolysis of the starch led to a lower yield of solid products (bio-chars) than the copyrolysis. They showed greater high heating values (up to 35 MJ/kg) than those arising from the latter process in agreement with their larger carbon content and lower presence of ash. In addition, the bio-chars produced at the highest process temperature presented an incipient pore development, suggesting their possible use as rough adsorbents or as intermediary for further upgrading to activated carbons. Furthermore, the pyrolysis of cassava starch and copyrolysis with peanut hulls generated gases, principally CO2, CO, CH4 and H2, that could help to sustain the processes. Chapter 18 - The potential to increase cassava products utilization is enormous if the available recipe range can be increased. A marketing survey was conducted in Mombasa, Nairobi and Busia urban centres. In Mombasa and Nairobi, marketing of cassava products was done daily. In Busia, daily marketing accounted for 22% while 78% was through a local market that opens twice a week. In Mombasa, 100% of cassava products were mainly sold at the main market (Kongowea). In Nairobi, 94% of respondents sold their products in local markets (Gikomba and Kibera) and 6% to hotels. In Busia, 50% sold their products at the


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main market and 50% in secondary markets. Sale of cassava products in Mombasa, Busia and Nairobi dates as early as 1956, 1962 and 1987, respectively. In Mombasa, cassava crisps and fried fresh cassava constituted 8% and fresh roots 92%. In Nairobi, boiled cassava constituted 6%, flour 25% and dried chips 69% of products being traded in. In Busia cassava flour constituted 33% and dried chips (for milling) 67% of the products sold. In Mombasa, the average price of a fresh root was 13 shillings during scarcity and 8 shillings during abundance. In Nairobi, a 2-kg tin (gorogoro) was sold at 69 and 55 shillings during scarcity and abundance, respectively. In Busia, the average price of a gorogoro was 35 and 31 shillings during scarcity and abundance, respectively. In Mombasa, the majority of those marketing cassava products were males while in Nairobi and Busia females dominated. The main products sold in Mombasa were crisps, fried chips, and fresh roots. In Nairobi, the main products were boiled cassava, flour and dry chips. In Busia, flour and dried chips were the main products. In Mombasa the major customers were final consumers, retailers and processors. In Nairobi major customers were final consumers, wholesalers, retailers and millers. In Busia customers were final consumers, wholesalers, retailers and processors. In Mombasa and Busia the principal suppliers of cassava products were both male and female while in Nairobi it was women. One of the main supply constraint reported was lack of cassava during scarcity. Competition from maize was cited in Mombasa and Nairobi. Costly transport was reported in Mombasa and Busia. In Mombasa, lack of credit was also cited. In Busia, other important constraints recorded were lack of sorghum and finger millet for blending cassava, and unfavourable weather for drying of cassava chips. Chapter 19 - The genetic improvement of cassava is directly related to the increase of productivity of culture, this has an important role in feeding in developing countries. Therefore, knowledge about the biology, distribution and conservation status of their wild relatives is essential, because it allows the harvest and conservation efforts to be directed to those unfamiliar species of which there are more severe threats. These data become even more relevant since some of their wild relatives are resistant to common diseases, such as whitefly. This chapter discusses the closest conservation of the wild relatives of cassava from the evaluation of biological collection, as well as recent collections by authors in Brazil and their cultivation in Germplasm banks. This work is part of a program of study of wild species of Manihot developed in partnership with the Federal University of Bahia Recôncavo (UFRB) and Cassava and Fruits National Research Center (CNPMF) of the Brazilian Agricultural Research Corporation (EMBRAPA) both located in Cruz das Almas, Bahia, Brazil. The program, started in 2010 aims to harvest and cultivate wild species of the genus with taxonomic, conservation and agronomic purposes, especially with regard to improving the cassava (M. esculenta Crantz). Harvests were made during the first six years of the project in four Brazilian regions encompassing 14 states and over 150 municipalities mainly from the central and eastern South America region. About 60 of the 80 south American species of Manihot in various environments were seen and harvested. Thirteen species phylogenetically close to cassava were selected to discuss their conservation status based on their occupation Area (AOO), Occurrence Extension (EOO), and potential use for the improvement of this culture. According to the International Union for Conservation of Nature (IUCN) criteria, all species showed some degree of threat, two considered Critically Endangered and the other Endangered according to AOO. The EOO analysis showed different results with only three endangered species, which can indicate subsampling of natural populations of these species. In preliminary studies among the analyzed species only three presented suggest valuable


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features to cassava improvement as resistance to pests and diseases, such as African cassava mosaic virus, bacterial blight, anthracnose, green mite and caterpillar ‘mandarová,’ or high dry matter content and protein in roots. However, the fact that some species were not included in the analysis, because they do not appear in the same M. esculenta clade, which also presents important features for improvement, suggests that they may also be the subject of breeding programs due to the ease of hybridization verified gender. Regular expeditions of harvest of wild species of Manihot, that were conducted since 2010 have helped to increase the distribution of data and also to broaden the panorama of each species ‘in loco,’ allowing the verification of their habitat conservation status, the number of individuals of each population, etc. However, expeditions have not been made yet specifically aimed at the closest relatives of cassava, covered in this study. It is emphasized that maintaining wild relatives of cassava germplasm bank is a practice of fundamental importance for the improvement of this culture, because the programs rely on the introduction of alleles with valuable agronomic traits contained in these species to minimize the limitations found in culture as pests and diseases.



In: Handbook on Cassava Editor: Clarissa Klein

ISBN: 978-1-53610-291-8 © 2017 Nova Science Publishers, Inc.

Chapter 1

COMPARISON OF CASSAVA AND SUGARCANE BAGASSE FOR FUEL ETHANOL PRODUCTION Yessica Chacón Pérez, Daissy Lorena Restrepo Serna and Carlos Ariel Cardona Alzate *

Instituto de Biotecnología y Agroindustria Laboratorio de Equilibrios Químicos y Cinética Enzimática Departamento de Ingeniería Química Universidad Nacional de Colombia sede Manizales, Manizales, Colombia

ABSTRACT During the last years, biofuels from different feedstocks have been studied and scaled up to industry to provide energy needing mainly for transport. Raw materials with high sugar content are mostly used in the production of biofuels as ethanol, butanol, hydrogen, etc. In the last years in tropical countries as Colombia, the ethanol production from starch and lignocellulosic biomass has been studied as a new alternative. Then, raw materials as cassava and sugarcane bagasse are presented as good options but more research is needed to understand the real advantages of these feedstocks. The amount of fermentable sugars obtained from the biomass is a decisive factor in the global yield of ethanol production. In this sense, different technological schemes can be proposed in the pretreatment step of the process followed by enzymatic hydrolysis to get the sugars. Starch-rich raw materials only require a milling and cooking as pretreatment. On the other hand, the pretreatment stage in some type of lignocellulosic materials must consider the reduction of particle size and specific technologies as dilute acid or alkaline methods. This chapter shows an analysis of ethanol production from cassava and sugarcane bagasse taking into account the availability, type and different pretreatment technologies to be applied to the raw material. Additionally, a technoeconomic and environmental assessment is performed, in order to compare the proposed processes.

*

Corresponding author: [email protected] (Carlos A. Cardona); Phone: (+57) (6) 8879300 ext. 55354.


2

Y. Chacón Pérez, D. L. Restrepo Serna and C. A. Cardona Alzate

Keywords: first and second-generation fuel ethanol, pretreatment step, cassava, sugarcane bagasse

1. INTRODUCTION 1.1. Worldwide Ethanol Production In the last decade, almost 73.33% of ethanol production in the world has been used as fuel in the transport sector [1], [2]. The interest in its production has increased due to its use as a fuel that reduces the greenhouse gases emission. However, this product cannot be fully used in internal combustion engines. Therefore, it has been used as an additive in oil, whose concentration varies between 3-10% depending on the policies of each country [3], [4]. In this sense, fuel ethanol has been produced in different countries around the world, as shown in Figure 1. This figure shows the distribution of fuel ethanol production in the world for the year 2015, with a global production around 74,847 thousand tonnes of oil equivalents [5]. United States is the largest producer of fuel ethanol in the world with a production of 14,700 million gallons with a sale cost of $ 1.52 USD per gallon. Brazil and the European Union are in the following places. Besides, in the last three years the exportation in United States increased from 200 to 800 million gallons of fuel ethanol, which has been destined to Canada (30%), Brazil (15%), China (8%), South Korea (8%), Philippines (8%), United Arab Emirates (3%), Tunisia (3%), Netherlands (3%), India (6%), Mexico (4%) and in the rest of the world (11%) [6].

Figure 1. World distribution of fuel ethanol production in 2015. Taken from: [5].


Comparison of Cassava and Sugarcane Bagasse …

3

1.2. Fuel Ethanol Feedstocks Fuel ethanol or bioethanol can be produced from different types of biomass as source of fermentable sugars [2]. The use of renewable biomass derived from agricultural crops instead of petroleum-based compounds reduces greenhouse gas emissions [7], [8]. Biomass can be classified into sugar-containing, starchy and lignocellulosic biomass [9]–[11]. Table 1 takes into account this classification to present the potential for fuel ethanol production of different agricultural crops and residues. As it is shown, the starchy biomass has a high potential and actually, raw materials as corn, wheat, barley and cassava are used due to their high content of starch for further production of fermentable sugars. This criterion has not been the only fact to select one or other biomass for fuel ethanol production. It is also influenced by the technology employed to obtain fermentable sugars, crop productivity, logistics, production cost, food security and others [12], [13]. However, the use of agricultural crops as feedstocks for the production of fuel ethanol represents a risk in food security, because population growth results in the need for more land to supply the human food chain. This is the main reason to use lignocellulosic biomass as an interesting raw material. Table 1. Yields of ethanol production with different feedstocks Feedstock

Ethanol yield (L/ton feedstock)

Ref.

Sugar-containing biomass Sugar cane Sugar beet Sweet sorghum Starchy biomass

70 100-110 60-80

[3], [10], [15], [16] [3], [17], [18] [3], [15], [16]

Corn

418.60*, 360-410

 Dry mill  Wet mill Rice Wheat Sweet potatoes Potatoes Cassava Barley Lignocellulosic biomass Straw (based on the content of cellulose) Grass (based on the content of cellulose) Wood chips (based on the content of cellulose) Wood chips (based on the content of cellulose and xylose) Wheat Straw Sugarcane Bagasse (acid hydrolysis process) Switchgrass * Average in the U.S. Industry for 2015 [6].

421.58 388.80 430 340-390 125 91-110 150-182 250-298

[3], [6], [10], [15], [16] [6] [6] [3], [16] [3], [15]–[19] [3], [16] [3], [16], [17] [3], [12], [15], [16] [3], [16], [17]

183 38 237 340 261.3 183-236 253.62-416.40

[17] [17] [17] [17] [10] [20], [21] [22]

Agricultural residues, forest biomass, herbaceous grass and some byproducts of agroindustrial supply chains are feedstocks of high availability in the world that are not used in food supply [11]. Furthermore, these raw materials have similar ethanol yields with respect to cassava. However, lignocellulosic biomass has a complex matrix formed by cellulose,


4


hemicellulose and lignin that creates some challenges when obtaining fermentable sugars compared to other biomass. This situation leaded to an intensive the search for more efficient and economical technologies [14].

1.2.1. Sugar-Containing Biomass Feedstocks based on sugar-containing crops are related mainly to high sucrose content. Some examples are sugar cane and sugar beets with an average content of 13.50%wt and 1215%wt, respectively [10], [23]. Although ethanol yields are not as high compared to starch (see Table 1), these plants are the most important crops in tropical and subtropical countries with large harvested areas destined to obtain refined sugar. Figure 2 shows the production of the sugar-containing crops (sugarcane and sugar beet) in the main countries that produce fuel ethanol. Sugar beet production is representative for the European Union using 11.2 million metric tonnes (MMT) for bioethanol production [24]. Czech Republic and some countries of Northwestern of Europe are the most representative countries, taking advantage of their high productivity of sugar beet crops. On the other hand, France and Germany have respectively 40% and 45% of fuel ethanol production based in the sugar content of this plant [24], [25].

Figure 2. Comparison of sugar-containing crops in different countries in *2013 and 2014. Based on: [25].

Sugarcane is used mainly by Brazil, India, Colombia and Argentina in the production of bioethanol, either from the extracted juice or molasses [26]–[29]. In the case of Brazil, the production is carried out from fresh sugarcane juice. Meanwhile, other countries as Colombia use the clarified syrup and byproducts from the evaporation and crystallization processes involved in the sugar refining [10], [30]. In 2014, Colombia used 24 MMT of the 38 MMT of sugar cane available (see Figure 2) to produce 2.39 MMT of sugar, 406 million liters (ML) of ethanol and 0.28 MMT of molasses [31]. Moreover, only 5% of China's bioethanol production is based in molasses (from cane or beet sugar plants), in contrast to Thailand where 66.66% of the installed plants depend on molasses, using approximately 4 MMT [28], [32], [33].



5

1.2.2. Starchy Biomass Cereals, roots and tubers crops present a high starch content since it is a reserve compound for most vegetables. Starch is a polysaccharide used in the field of syrups and biofuels. For using the starch to produce biofuels, it is necessary to perform a hydrolysis to break down the carbohydrate bonds and then to obtain fermentable sugars. This process has a theoretical yield of 111 grams of glucose per 100 grams of starch [19]. Glucose is present in the chains of amylose and amylopectin responsible for the functional properties of starch. Amylose represents nearly 25% of starch, it has a straight chain of glucose joined by glycosidic alpha (1,4) bonds and it is responsible for starch gelation. The composition of amylose in cereal grains varies from 26-28%, while in the roots and tubers accounts for 1723%. The other 75% of starch is the amylopectin, which helps to thicken but not in gel formation [34]. Figure 3 shows the production of starch crops in the main countries producing fuel ethanol. It is evidenced that the highest production of cereals is distributed between corn and wheat in the United States, China, Brazil and European Union. Currently, there is a huge predilection for producing fuel ethanol from corn since the starch content in corn kernel (i.e., 60.59% wt. wet basis) is higher than other grain crops [10]. In the United States, corn is used for fuel ethanol while sugar beet is used to obtain refined sugar. The high ethanol productivity from corn in United States is related to the great technological and genetic development, which has enhanced the hydrolysis of starch into fermentable sugars or increasing the starch content in corn crops. In 2015, the ethanol production in the United States was 473 gallons per acre of corn, from which 90% were produced by dry mill and the remaining 10% by wet mill [6]. In contrast, the fuel ethanol production of other countries come from corn and other grain cereals, roots and tubers with the exception of Argentina who use also molasses or juice [28]. Some countries as Canada, China, Thailand and some in the European Union use wheat, barley, rye, rice or cassava, to supply part of their transport sector requirements. In 2014, the 24% of fuel ethanol production of Canada was derived from wheat using 1 MMT of this crop [35]. In 2015, 5,250 ML of fuel ethanol were produced in the European Union using 10.1 MMT of its cereals production as corn in Central Europe and Spain, wheat in Northwestern Europe, barley and rye in Germany, Poland, Baltic Region and Sweden [10], [24]. On the other hand, 70% of the ethanol production in China was based on corn and cassava. The use of Cassava in China and other countries has increased due to fuel alcohol government policies, which provide several economic benefits to improve energy production and reduction in CO2 emissions [32]. In Thailand, approximately 10 MMT of fresh cassava tubers were consumed annually as a starchy staple in natural or fermented forms [36] and 0.97 MT are destined to supply six ethanol plants with a daily production of 1.5 ML fuel ethanol in 2014. The main objective of the Thailand government is to increase the ethanol production up to1.9 ML per day using 0.5 MMT per year of rice and the implementation of other ethanol plant based on cassava [33]. The high productivity of this crop with respect to other countries shown in the Figure 3 and its yield of 223 ton of cassava per harvested hectare makes this raw material the more viable for fuel ethanol production in this country, taking into account the availability and low cost [25]. On the other hand, the production of Cassava in Colombia (3 MMT) is not at the same level with respect to other countries as Thailand (30 MMT).


6


Figure 3. Comparison of starch crops in different countries in *2013 and 2014. Based on: [25].

1.2.3. Lignocellulosic Biomass The energy outlook in recent years have led to identify a new generation of biofuels. These are known as second generation biofuels, which are derived from cheaper raw materials that are not used in the food sector and have a large availability like lignocellulosic biomass [30], [37], [38]. The glucose present in the cellulose is the fermentable sugars available for producing the so known cellulosic ethanol. The yield of the cellulosic ethanol production from these materials can vary according to the composition of the lignocellulosic biomass due to the difference of grow conditions in the crops, the performance of the technological route used to obtain fermentable sugars and the strains used to consume hexoses or both hexoses and pentoses.



7

Table 2. Companies around the world producing cellulosic ethanol Company

Level

Capacity Location (MGy*)

Feedstock

Process

Biochemical processes

Crescentino

Commercial

20

Demonstration

0.25

Commercial

30

American Process Inc.

Pilot

0.8

Abengoa

Commercial

25

Project LIBERTY (Poet-DSM)

Commercial

20

Pilot

0.05

Pilot

0.2

Commercial

Approx. 22

DuPont

Edeniq

GranBio

Patented Process Proesa®: pretreatment with steam, reduction of viscosity, SSCF process and distillation [40], [44]. Vonore, Corn stover and Pretreatment with dilute Tennessee switchgrass ammonia (low temperature and pressure), saccharification, Nevada, fermentation with Zymomonas Corn stover Iowa mobilis and distillation [45]. Technology GreenPower+®: Pretreatment with hot water, Alpena, Woodchip concentration and hydrolysis of Michigan waste hemicellulose with dilute-acid sulfuric, fermentation and distillation [46], [47]. Thermochemical pretreatment, Wheat straw, Hugoton, enzymatic hydrolysis, corn stover and Kansas fermentation and distillation grass crops [40], [46]. Acid pretreatment, enzymatic Emmetsburg, hydrolysis, fermentation with Corn cobs Iowa GMO yeast and distillation [6], [48]. Corn stover and Pretreatment with their Visalia, sugarcane crushing technology, enzymatic California bagasse hydrolysis with proprietary additives to boost and stabilize São Paulo Sugar cane enzyme activity, fermentation State bagasse and distillation [40], [49]. Pretreatment with technology São Miguel Sugarcane Proesa®, enzymatic hydrolysis, dos Campos, straw and fermentation with CF process Alagoas bagasse and distillation [50]. Province of Vercelli

Wheat straw, rice straw and Arundo donax (giant cane)

Edmonton, Alberta

Sorted MSW, residual biomass and other nonhomogeneous waste

Thermochemical processes

Enerkem

Commercial

10

Gasification to obtain synthesis gas, purification, catalytic synthesis and purification [40], [51].

Thermochemical/biochemical processes Ineos Bio

Commercial

8

Vero Beach, Vegetative and Florida wood waste

Gasification to obtain synthesis gas, gas conditioning for the fermentation with Clostridium ljungdahlii and distillation [52].

* Million U.S. Gallons of fuel ethanol per year. Based on [40]–[43], [46].

There is a special interest in the agricultural residues derived from corn and sugar cane to be used for fuel ethanol production. The main reasons are the residue to product ratio (RPR) and the crop productivity as seen in Figures 2-3 [25], [39]. The RPR for residues of corn crop


8


are 0.273 for cobs, 2 for stalk and 0.2 for husk. In the United States, this represents 99 MMT, 722 MMT and 72 MMT, respectively. In sugar cane processing, the main residue is sugarcane bagasse with a RPR of 0.29, which represents 214 MMT for Brazil and 11.07 MMT for Colombia. Using the sugarcane bagasse as hexoses and pentoses feedstock for producing fuel ethanol in Colombia it would be increased the production around thirteen times with respect to the 406 ML of fuel ethanol produced in 2014. Nowadays, the most representative countries in the production of cellulosic ethanol are United States, Brazil and some of Europe countries with pilot and commercial scale plants, taking advantage of the availability and proximity of lignocellulosic biomass to the processing location [15], [40]. These have been endorsed by state programs or by great leaders in fuels production companies. Some of these companies are presented in Table 2. In Europe, one of the largest biorefineries with very advanced technology has been implemented. Located mainly in Italy, Crescentino currently is dedicated to the cellulosic ethanol production. However, the company is aiming also to produce n-butanol, an alcohol of great interest for oil companies due to its similarity with gasoline. Furthermore, United States has several projects focused on cellulosic ethanol production or a precursor of this (i.e., syngas) from lignocellulosic biomass like corn stover (corn cobs, leaves and stalks), switchgrass or other sources of non-food material as paper and municipal solid wastes. In Brazil, the production of ethanol has focused on the use of fermentable sugars present in sugarcane bagasse and straw through a biochemical process in the GranBio’s Bioflex I industrial unit [40]. Also, Canada is using municipal solid wastes through gasification to produce synthesis gas and subsequently, ethanol by catalytic synthesis [41]–[43].

1.3. Stages of the Fuel Ethanol Production 1.3.1. Pretreatment and Hydrolysis Stage As shown in Table 2, in biochemical processes, different pretreatments are proposed to dissociate the cellulose-lignin complex present in lignocellulosic biomass and the same happens to treat the starchy biomass only that it is a well-established technology. This stage is only a conditioning of raw material, for which it is necessary to carry out the hydrolysis of cellulose and starch to obtain fermentable sugars, respectively [14], [53]. For both cases, the pretreatment begins with a milling step to increase the contact area for the next stages of the process (Figure 4). The other technologies used to pretreat the biomass aim to break down the intermolecular bonds of starch and improve the cellulose accessibility [54]. After the pretreatment step and depending on the material, the hydrolysis process is performed using enzymes or chemical agents but it is better to use enzymes since the use of chemicals involves the presence of toxic compounds for fermentation and the utility cost is low compared with acid or alkaline hydrolysis given the low operation cost [14], [55]–[57]. Then, the pretreatment and hydrolysis stage determine the differences in yields and production costs for obtaining fuel ethanol from these two materials. In the starchy materials, the process involved to obtain fermentable sugars begins with heating to solubilize the starch. Here occurs the starch gelatinization and the conditions depends on gelatinization temperature that varies according to the starch biomass but generally a temperature of 80°C is used [57]–[59]. Then the cooked material is partially hydrolyzed with α-amylase and viscosity decreases [10]. This first hydrolysis is known as



9

liquefaction, which is carried out at temperatures between 80 to 90°C with the appropriate amount of alpha amylase and an uniform agitation [10], [60], [61]. The partially hydrolyzed starch is treated with amyloglucosidase to obtain a glucose-rich solution to be used in ethanol fermentation [62]. In order to obtain a solution of fermentable sugars from the polysaccharides presents in lignocellulosic biomass different technologies have been distinguished over time. Some of these are described in Table 3. The enzymatic hydrolysis of cellulose is carried out by cellulases, which are highly specific. This process is usually conducted at mild conditions (i.e., pH 4.8 and temperatures between 45-50°C) [14], [55], [56]. Lignocellulosic biomass

Starchy biomass

Milling

Milling

Pretreatment technology

Cooking

Acid hydrolysis

Saccharification with cellulases

Liquefaction with α amylase Saccharification with amyloglucosidase

Fermentable sugars

Pretreatment

Hydrolysis

Figure 4. Pretreatment and hydrolysis stage to obtain fermentable sugars.

1.3.2. Fermentation Stage In addition, some configurations are designed for reducing the operation times and avoiding the inhibition of enzyme activity due to the accumulation of hydrolyzed sugars in the fuel ethanol production. This is the case of Separate Hydrolysis and Fermentation (SHF) [71]. The hydrolysis and fermentation in one stage, known as Simultaneous Saccharification and Fermentation (SSF) is presented in Figure 5 [72]. In this scheme the sugars produced during hydrolysis are immediately fermented into ethanol and then the problems associated with sugar accumulation and enzyme inhibition as well as contamination can be avoided [72]. Furthermore, this reduces the fermentation times, lowers enzyme requirement and increases productivity. Given that SSF process can use a single reactor and the same temperature for saccharification and fermentation process, this decreases capital costs [73]. It has been applied in some starch based commercial ethanol processes [74]. Other configuration is a variation of the SSF process referred to as Simultaneous Saccharification and CoFermentation (SSCF), which is applied mainly to the use of lignocellulosic materials [10]. In this scheme, pentose fermentation is included using a modified microorganism capable of metabolizing it, thus taking place a simultaneous fermentation of pentoses and hexoses [71].


10

Y. Chacón Pérez, D. L. Restrepo Serna and C. A. Cardona Alzate Table 3. Pretreatment technologies used to pretreat lignocellulosic biomass

Type pretreatment

Steam explosion

Physicochemical

AFEX

Acid

Chemical

Alkaline

Biological

Process description The biomass is pretreated with high-pressure saturated steam and then, the pressure is swiftly reduced, which makes the materials undergo an explosive decompression. The process is typically initiated at a temperature of 160-260°C for several seconds to a few minutes. The lignocellulosic materials are exposed to liquid ammonia at high temperature and pressure for a period and then, the pressure is swiftly reduced. The dosage of liquid ammonia is 1-2 Kg ammonia/Kg dry biomass, temperature 90°C and residence time 30 min.

Observation

Ref.

The process causes hemicellulose degradation and lignin transformation due to high temperature, thus increasing the potential of cellulose hydrolysis. The factors that affect this process are residence time, temperature, chip size and moisture content.

[55], [56], [63], [64]

The AFEX process was not very effective for the biomass with high lignin content and does not produce inhibitors for the downstream biological processes, so water wash is not necessary. AFEX pretreatment does not require small particle size for efficacy It is responsible for solubilize It can be carried out with partial hemicelluloses and mineral acids (H2SO4, HCl, improve the accessibility of HNO3 and H3PO4) generally it is enzymes to cellulose. Its cost is used H2SO4 a diluted usually higher than some concentrations between 0.5-5% physicochemical pretreatment (w/v) at temperatures low than processes. A neutralization of 160°C and solids loading pH is necessary for downstream between 10-40%. enzymatic hydrolysis or fermentation processes. Alkali pretreatment processes This process depends on the use lower temperatures and lignin content of the materials. pressures than other Compared with acid processes, pretreatment technologies. alkaline processes cause less However, the residence time are sugar degradation, and many of in the order of hours or days the caustic salts can be rather than minutes or seconds. recovered and/or regenerated. In biological pretreatment processes, microorganisms such as brown-, white- and soft-rot fungi are used to degrade lignin The advantages of biological and hemicellulose in waste pretreatment include low energy materials. Brown rots mainly requirement and mild attack cellulose, while white and environmental conditions. The soft rots attack both cellulose rate of hydrolysis in most and lignin. White-rot fungi are biological pretreatment the most effective processes is very low basidiomycetes for biological pretreatment of lignocellulosic materials


[55], [65]

[55], [65]– [67]

[55], [66], [68]

[55], [66], [69], [70]


11

Figure 5. Differences between schemes of SSF and SHF processes.

2. METHODOLOGY Although the formation of fermentable sugars from starchy and lignocellulosic biomass are identified for requiring intense conditions of pretreatment, it should be noted that the technologies used have some differences in energy consumption, equipment requirements, among others, that affect the ethanol yield and production cost. These differences have been the starting point for different laboratory and simulation research aiming to provide the best conditions for the implementation of these fermentations at commercial level. Considering this, in this chapter a techno-economic and environmental analysis of fuel ethanol production was carried out using the software Aspen Plus V8.2®. The analysis is carried out in Colombia context with cassava and sugarcane as different feedstocks that have been studied as a new alternative for ethanol market. The process proposed for each feedstock involves conventional pretreatment technologies presented in Figure 4 to avoid technological limitations. For the fermentation stage, the SHF scheme was considered to ferment the hexoses derived of starch and a co-fermentation for the hexose and pentose derived from sugarcane bagasse. Given that different feedstocks and technologies have been used to obtain the fermentable sugars and fuel ethanol, it is necessary to define the feed flow as the point of comparison. The feed was 9.87 ton of biomass per hour in both processes with the composition presented in Table 4. The amount of fermentable sugars is varying given the composition of each raw material. In the case of a complete conversion of starch of cassava, 2616.34 kg of fermentable sugars per hour could be obtained, compared to 3529.59 kg of fermentable sugars per hour from the cellulose and hemicellulose of sugarcane bagasse. However, the technologies limitations in this process allow having 1794.81 kg/h and 2181.29 kg/h of fermentable sugars, respectively. According with this behavior, the amount of fermentable sugars available for ethanol fermentation are higher for sugarcane bagasse than in cassava.


12


Table 4. Composition in weight percentage in wet basis of the raw materials used for studying fuel ethanol production Component Moisture Cellulose Hemicellulose Lignin Protein Starch Ash Source: a [75], b[21].

Cassavaa 71.40 0.26 0.33 0.01 0.80 26.50 0.70

Sugarcane bagasseb 50.00 23.70 12.05 11.70 2,40 . 1.15

2.1. Process Design 2.1.1. Cassava Case The production process of fuel ethanol consists of the following steps: Conditioning and pretreatment, biotransformation, separation and purification. The design of the ethanol production process is based on the process developed for corn by Cardona and Quintero et al. [10], [75], which is presented in Figure 6. The fresh cassava is subjected to a process of chopping and sieving, to reduce its size up to 4 mm. Then, a gelatinization process is applied to dissolve polysaccharides aiming to improve the enzymatic hydrolysis step. This process is carried out at temperatures higher than gelatinization (i.e., 63°C) with continuous agitation to decrease viscosity and prevent the formation of gel when it is cooled [76]. To obtain a partial starch hydrolysate (liquefied starch), cooked starch is subjected to a treatment with αamylase. This treatment takes place in a bioreactor at 88°C, obtaining a hydrolysate of cassava. Hydrolysate is then sent to a bioreactor where amyloglucosidase is added to convert starch fragments into glucose. The glucose solution is sent to another bioreactor in which the sugar is converted into ethanol using Saccharomyces cerevisiae at 31°C. The yeast biomass is separated by conventional sedimentation. The liquor obtained contains a concentration of 8 – 10% in weight of ethanol. This is destined to a conventional separation process identified for first generation fuel ethanol process. This process begins with distillation followed by rectification. The distillation was performed at 1 bar obtaining an ethanol concentration of 56.7% and subsequently, the rectification process increased the concentration up to 86.7%. Finally, the ethanol from the rectification stage was preheated and then, it is sent to an adsorption stage using molecular sieves. The adsorption process was carried out in two columns which comprises the pressurization of the column (using the preheated distillate from the rectification column), adsorption of water (the product is continuous removed), and desorption of water. Desorption of water was carried out at 0.14 atm [77]. Vapors resulting from the desorption process were recycled back to the rectification column where the ethanol was recovered. From one of the adsorption columns, ethanol was recovered at 99.5%v/v, whereas the other column is regenerated.



13 Water

Cassava

α-amylase solution

Water

S. cerevisiae and nutrients

Glucoamylase

CO2 and ethanol

Absorber

CO2

Sieve Dextrins

Impurities

Cooking

Saccharification reactor

Liquefaction reactor

Fermenter Sedimentation

Regenerate

Evaporator

Molecular sieves

Distillation

Rectification

Yeast

Mixer

Dehydrated Ethanol Waste water

Stillage

Figure 6. Flowsheet of fuel ethanol production for the Cassava case. Rectangles concerns to raw materials (blue), intermediaries (purple), product (green) and byproducts (red) of the process.

2.1.2. Sugarcane Bagasse Case The process scheme implemented in the simulation for this case is shown in Figure 7 and it is based on previous works [30], [78], [79]. First, the particle size reduction to a 16 mesh screen with the assistance of milling and sieving equipment is carried out. Then, a pretreatment step with chemical reagents is implemented aiming to increase the accessibility of the cellulose by means of the hemicellulose solubilization [67], [80]. Pretreatment using dilute sulfuric acid (0.9%wt.), 160°C and a solid load of 10%wt. was selected based on previous reports [81]. After the dilute acid pretreatment, it is necessary to wash the solid fraction in order to recover the hydrolyzed sugars and neutralize the solid fraction. The separation of the solid and liquid fractions was done with a filter. The liquid fraction has toxic compounds from the pretreatment step as furfural, HMF and acetic acid which are fermentation inhibitors [82], [83]. For this reason, it is necessary to remove inhibitors from the liquid fraction using temperature and chemical agents. Detoxification is a well-known method to remove these toxic compounds using calcium hydroxide at 60°C and then, the pH is adjusted for the co-fermentation process [84]. During neutralization, calcium sulfate (gypsum) is formed and precipitated by the pH change and it is removed by filtration. From this procedure, it is obtained a xylose liquor that is used in the co-fermentation. The solid fraction from the acid pretreatment can be denominated as cellulignin (i.e., fiber without hemicellulose) and it is an intermediary in the global process that can be easily digested by cellulase and β-glucosidase in a citrate buffer. Enzymes hydrolyze the glycosidic bonds of cellulose to obtain glucose and cellobiose units, a disaccharide composed of two glucose


14


molecules linked by (1-4)-β bonds, which subsequently are broken to obtain monosaccharides. Saccharification reactor is operated at 50°C with a solids loading of 10% and then, the temperature is increased up to 90°C during five minutes for enzyme denaturalization. The remaining solid composed mainly of lignin is removed with the aid of a filter and the liquid fraction is concentrated to obtain the glucose liquor that it is mixed with the xylose liquor to carry out the co-fermentation. Co-fermentation process used a recombinant bacterium Z. mobilis with a plasmid pZB5. The plasmid is responsible for gene expression of xylose isomerase, xylulokinase, transketolase involved in the metabolic pathway to digest xylose and produce ethanol at a temperature of 30°C [85]. Separation and purification steps are the same procedures mentioned before in Section 2.1.1. Sugarcane bagasse

Water

Steam Evaporator

Sulfuric acid Crusher

Filter

Sulfuric acid Ca(OH)2

Washing

Filter

Hemicellulose hydrolysis reactor

Cellulignin Neutralization reactor

Detoxification reactor

Gypsum

Enzyme solution

Steam Evaporator

Xylose liquor

Filter Regenerate

Mixer

Lignin Saccharification reactor

Glucose liquor

Rectification

CO2

Mixer Dehydrated Ethanol Waste water

Distillation

Sedimentation

Evaporator

Molecular sieves

Bacterium

Co-fermentation reactor

Z. mobilis and nutrients

Stillage

Figure 7. Flowsheet of fuel ethanol production for the Sugarcane bagasse case. Rectangles concerns to raw materials (blue), intermediaries (purple), product (green) and byproducts (red) of the process.

2.2. Simulation Procedure Simulation of the presented processes schemes is based on reports of different authors. Aspen plus V8.2 (AspenTech, USA) commercial software has a wide content of physicochemical properties, thermodynamic models and equipment that allows handling solids, liquids and gases in order to design processes and determine their material and energy balances. It is highly important to consider the thermodynamic properties of organic and



15

inorganic compounds present in biomass such as proteins (lysine), hemicellulose, lignin and ash presented by the National Renewable Energy Laboratory (NREL) [86]. During simulation procedure, the thermodynamic models used to represent the behavior of liquid and vapor phases were NRTL (Non-Random Two Liquid) and Hayden O’Connell EOS to obtain the activity coefficient and fugacity. A feed of 9.87 ton/h of raw material are pretreated and hydrolyzed using stoichiometric conversion of starch to dextrins and then to glucose [87]. The kinetic model used to describe the dilute acid pretreatment of the lignocellulosic biomass was proposed by Esteghlalian et al. [81] and Quintero et al. [21], [30]. The conversion of cellulose through enzymatic hydrolysis is based on the stoichiometry reaction presented by Da Silva Martins et al. [82]. For co-fermentation, user model is used to describe non-structured and non-segregated models of Z. mobilis with kinetic parameters reported by [85]. Finally distillation columns were simulated considering the methodology mentioned by Quintero et al. [38], [75].

2.3. Economic Analysis The economic evaluation is carried out using the mass and energy balances from the software Aspen Plus® aiming to determine the size and amount of utilities required by the equipment involved in the process. Sizing and profitability of the process schemes were calculated in the complementary software Aspen Process Economic Analyzer V8.2. The depreciation of capital was calculated based on the straight line method for a project life of 10 years. From this assessment, the ethanol production cost was evaluated. Economic parameters in the Colombian context (tax rate and interest rate), raw material and utilities costs reported in previous works [75], [78], [79], [88], [89] were considered in this evaluation. Table 5 summarizes the data used in the economic assessment of the proposed process schemes. Table 5. Investment parameters and prices used in the economic analysis Item Investment Parameters Tax rate Interest rate Raw materials Cassava Sugarcane bagasse Sulfuric acid Calcium hydroxide Cellulase Utilities LP steam MP steam HP steam Potable water Fuel Electricity Operation Operator Supervisor

Unit

Value

Ref.

% %

25 17

[88]

USD/kg USD/kg USD/kg USD/kg USD/kg

0.038 0.010 0.094 0.056 1.0

USD/tonne USD/tonne USD/tonne USD/m3 USD/MMBTU USD/kWh

1.57 8.18 9.86 1.25 7.21 0.10

USD/h USD/h

2.14 4.29


[75] [89] [88] [89]

[78]

[88]

[88]

16


2.4. Environmental Analysis The environmental analysis of the proposed cases is evaluated using the software developed by the Environmental Protection Agency (EPA): Waste Algorithm Reduction (WAR GUI). This software determines the potential environmental impact (PEI) per kilogram of product from the generated impact by inhalation and concentration of components in the output streams of the process, and the energy process according to power source [90]. The software evaluates the environmental impact based on eight categories: Human Toxicity Potential by Ingestion (HTPI), Human Toxicity Potential by Exposure (HTPE), Terrestrial Toxicity Potential (TTP), Aquatic Toxicity Potential (ATP), Global Warming Potential (GWP), Ozone Depletion Potential (ODP), Smog Formation Potential (PCOP) and Acidification Potential (AP) [90]. Besides, it was considered three different sources of conventional energy in the process schemes in order to analyze the relation between the impact categories and the generated contamination from these energy sources.

3. RESULTS AND DISCUSSION 3.1. Fuel Ethanol Production Based on the composition of raw material presented in Table 4, the yields of ethanol per ton of feedstock expected were 190.13 L/ton of cassava and 258.7 L/ton sugarcane bagasse (considering the cellulose and hemicellulose content). However, the proposed processes schemes only achieves between 73 to 53% of the theoretical yield and even lower values than reported for stand-alone processes presented in Table 6. In the sugarcane bagasse case, the difference can be attributed to the physicochemical composition of the raw material, especially the moisture content that reduces the quantity of available cellulose and hemicellulose based on the information reported by Quintero et al. [30]. In the Cassava case, the different yield obtained in this work compared with that from Cardona et al. [91] can be attributed to the enzymes efficiency. This behavior reflects the influence of different existing technologies for obtaining fermentable sugars from this biomass. In this sense, different technologies such as simultaneous saccharification and fermentation (SSF) or even more innovative process known as simultaneous liquefaction, saccharification and fermentation (SLSF) can be considered for the cassava case aiming to improve yields. Moreover, the behavior of the process yield can be attributed to the microorganisms used in the fermentation step because of the different metabolic pathways for consuming the substrates. In the lignocellulosic biomass case, the results evidence that the fuel ethanol production (33,099 liters of ethanol per day) was very close to the yield obtained from cassava (32,654 liters of ethanol per day). The use of this raw material present a great opportunity for fuel ethanol production instead of Cassava; despite the great productivity of this crop in the world (i.e., 102.26 tons of cassava per Ha [25]). Due to the cassava is mainly used in the food industry, its availability is limited to be destined for biofuels production. This behavior is reflected in the use of 60% of cassava world production in the food industry, 33% animal feed and only 7% in the industry of textile, paper, food and fermentation [92]. On the other hand,



17

the amount of generated sugarcane bagasse in the world annually is close to 151.2 MMT for 540 MMT of sugarcane dry processed [63]. In the case of based-fuel ethanol production from cassava, it should be considered the use of bitter species that do not affect the market prices and food security, especially in developing countries. Table 6. Ethanol production yields using as feedstock cassava and sugarcane bagasse Yield (L/ton)

Feedstock Cassava Solid-state ethanol fermentation Liquefaction and SHF with yeast Liquefaction and SSF with yeast Liquefaction and SSF with bacterium Z. mobilis Liquefaction and SHF with yeast Liquefaction and SHF with yeast Sugarcane bagasse Stand-alone From cellulose and hemicellulose in co-fermentation From cellulose and hemicellulose fermented with different microorganisms From cellulose and hemicellulose in co-fermentation Biorefinery context (from cellulose) (from hemicellulose)

Reference

361 164.47 184.07 181.03 166.80 139.69

[93]

74.55

[30]

323.19

[89]

137.81

This work

56.37 92.78

[94]

[75] [91] This work

3.2. Economic Assessment Table 7 presents the results of the economic analysis. From these results, the cost of fuel ethanol production and the profit margin are determined, for each process, assuming a sale price in Colombia of 1.24 USD/L [78]. Additionally, it is presented the share of the operating and financing costs. The economic feasibility of process schemes has a profit margin of 65.16% for Cassava and 47.66% for sugarcane bagasse. Production cost of fuel ethanol from Cassava is lower than the sugar cane in Brazil (0.47 USD/L) and it is higher compared with other countries as Thailand (0.18 USD/L) and other raw material such as corn in United States (0.40 USD/L) and wheat in Europe (0.42 USD/L) [6], [13], [95]. This difference is attributed to the market price of Cassava in countries such as Thailand, where the crop productivity is higher than the demand, which allows the reduction in the cost of raw material and at the same time, the fuel ethanol production cost. Based on this statement, the logistic of the Cassava supply chain must be considered aiming to reduce the cassava purchase price in the fuel ethanol production. Currently, the distilleries are located near to the sugarcane supply chain in order to mitigate the economic impact of the logistics issues.


18

Y. Chacón Pérez, D. L. Restrepo Serna and C. A. Cardona Alzate Table 7. Fuel ethanol production cost from cassava and sugarcane bagasse case

Item Raw Materials Utilities Operating Labor Maintenance Operating Charges Plant Overhead General and administrative Depreciation of Capital Production cost (total) Profit margin (%)

Cassava case Share of total USD/L cost (%) 0.272 62.91 0.027 6.34 0.008 1.80 0.005 1.13 0.002 0.45 0.006 1.46 0.026 5.93 0.086 19.99 0.432 100.00 65.16

Sugarcane bagasse case Share of total USD/L cost (%) 0.309 47.7 0.178 27.4 0.008 1.2 0.007 1.0 0.002 0.3 0.007 1.1 0.041 6.3 0.097 15.0 0.649 100.0 47.66

In sugarcane bagasse case, the production cost of fuel ethanol is lower than the first generation fuel ethanol since high equipment in pretreatment stage are required. However, the production cost from sugarcane bagasse is similar to that from sugar beet in France (0.60 0.68 USD/L) [95]. With respect to other lignocellulosic biomass, the fuel ethanol production cost was similar to that from empty fruit bunches 0.57 USD/L, rice husk 0.63 USD/L, coffee cut-stems 0.68 USD/L and lower for Plantain Pseudostem 2.49 USD/L due to the differences in physicochemical composition and raw material costs [30], [79]. Besides, the production cost was similar to that reported in United States when corn stover is used as raw material [95]. This behavior represents an advantage for Colombia because, as mentioned in Section 1.2.3, both lignocellulosic biomass are considered main wastes of each country. This can enhance the market of fuel ethanol if it is implemented different pretreatment technologies that improve the formation of fermentable sugars. The utilities share for the ethanol production from sugarcane bagasse is higher than the Cassava case because of the amount of required energy in the pretreatment steps. Another parameter that has the highest influence in the production costs is the depreciation due to the high number of corrosion-resistant equipment required. Due to the high energy requirements of both processes, it is necessary the implementation of alternatives in order to reduce them. An alternative of energy and steam production could be the use of wastes from cassava crop (i.e., stems and leaves) or the produced lignin in the sugarcane bagasse case as raw material for gasification, pyrolysis or combustion technologies. Therefore, it would be achieved a better use of biomass and reducing wastes generated in the production process. The biggest impact would be reflected in the decrease of the production costs because of the reduction in the utilities costs with the implementation of this alternative.

3.3. Environmental Assessment Figure 8 presents the results of the potential environmental impact (PEI) calculated using the software WAR. In this figure is shown the comparison of three sources of energy (coal, gas and oil) for both feedstocks. In the Cassava and sugarcane bagasse case, the fuel that



19

generated the lowest environmental impact per kilogram of product was the natural gas. In the case of the ethanol production from cassava and using natural gas as fuel, a negative PEI was obtained, which means a reduction of pollution in the environment. In other words, the generated wastes in the process are less polluting than the raw material used in the process scheme. The highest environmental potential is evidenced in the acidification potential because of the amount of CO2 release from the fermentation process. The environmental impact of this indicator changes based on the energy source that is implemented in the process since each fuel generates different amounts of CO2 in the combustion process. It is noteworthy that a previous analysis of the energy source used in each process scheme is required. The microorganism and the pretreatment procedure for each raw material are the most important differences in the evaluated processes. As a consequence, the amount of generated wastes varies. Although, the production of ethanol from the two processes does not present great difference. The ethanol purification generates a large quantity of wastes, mainly by the metabolism of the microorganism.

Figure 8. Potential environmental impact per kg of fuel ethanol using cassava and sugarcane bagasse as raw material.

Table 8 presents the amount of generated residues from both processes. The ethanol production from sugarcane bagasse generates more than three times the amount of stillage


20


when cassava is used as feedstock. The same behavior is evidenced in the liberation of CO2 from the process, which is 1.2 times higher than that generated with cassava. When sugarcane bagasse is used as raw material, other wastes, besides to those already mentioned, are obtained, which are the result of the acid pretreatment and detoxification process. The use of sugarcane bagasse as raw material increases the amount of generated wastes in comparison to cassava. Table 8. Wastes obtained in the ethanol production Waste Process [L/h] Wastes CO2 emission Stillage

Cassava 28.72 1334.25 13671.52

Sugarcane bagasse 60428.35 1701.76 46346.79

Table 9 presents the generated wastes during the pretreatment with dilute acid using sugarcane bagasse. The pretreatment of the sugarcane bagasse uses different reagents and it is also necessary to carry out detoxification processes in order to remove toxic compounds for both enzymatic hydrolysis as for fermentation. Table 9. Products generated during dilute acid pretreatment of sugarcane bagasse Component Sulfuric Acid Calcium Oxide Calcium Hydroxide Protein Glucose Xylose Furfural Cellulose Xylan Lignin Calcium Sulfate Ash Total

Flow [L/h] 0.76 0.12 80.97 28.99 127.80 92.43 0.29 1,399.04 37.67 1,110.96 1,538.43 32.56 4,450.02

Table 10 presents the composition of stillage obtained from both processes. In the cassava case, it is evidenced that other components are presented such as ash, cellulose, dextrin, glucose, hemicellulose, protein and biomass. Compared with cassava, the stillage obtained from sugarcane bagasse present different components in smaller proportions. Table 10. Stillage stream composition of the ethanol production Component Ash Cellulose Dextrin Ethanol Glucose

Cassava (%) 0.50 0.11 0.19 0.00 0.56

Sugarcane bagasse (%) 0.00 0.00 0.00 0.23 0.00


Comparison of Cassava and Sugarcane Bagasse … Component Hemicellulose Protein Water Yeast

Cassava (%) 0.14 0.58 97.57 0.31

21

Sugarcane bagasse (%) 0.00 0.46 98.06 1.23

3.3.1. Energy Analysis Table 11 presents the energy consumption for each stage of the ethanol production using as feedstock cassava and sugarcane bagasse. The stages considered in the energy analysis are: milling and pretreatment, hydrolysis, fermentation, separation, purification and the concentration of stillage. In this sense, it is observed that when cassava is used as a feedstock 40.52 MJ per liter of ethanol are required. The ethanol production using sugarcane bagasse required 241.10 MJ/L of ethanol, which is higher than the cassava case. The hydrolysis and fermentation stage have the highest contribution to the energy consumption in the case of sugar cane bagasse. This behavior is evidenced since in this process scheme was considered the neutralization and evaporator of xylose and glucose to obtain the liquors rich in fermentable sugars. This process is high energy consumption in comparison to liquefaction, saccharification of starch and fermentation stage in both cases. Despite both processes have the same separation and purification stage, a significant difference in the energy consumption of each case is evidenced. Table 11. Energy consumption per stage in the production of ethanol Feedstock Stage Milling and pretreatment Hydrolysis and fermentation Separation and purification Stillage concentration Total

Cassava MJ/h

MJ/L

Percentage

Sugarcane bagasse MJ/h MJ/L

Percentage

2,103.71

1.53

3.76

64,369.49

47.31

19.62

8,761.07

6.35

15.68

124,165.17

91.26

37.85

16,016.05

11.61

28.66

37,371.69

27.47

11.39

29,005.26

21.03

51.90

102,125.13

75.06

31.13

55,886.09

40.52

100.00

328,031.47

241.10

100.00

3.4. Food vs Fuel Production The use of cassava as food for human consumption generates a controversy when it is used as a feedstock for the fuel generation because of the availability of this food for the human being would be diminished. With the growing demand for fuels, croplands are destined to meet these energy needs. The use of cassava as a feedstock for ethanol production is not feasible in countries that have low production; but in countries where its production is high and has the ability to increase croplands of this raw material, this would be an alternative for biofuel production. In comparison with the sugarcane bagasse considered as residue of sugar production without important food security problems (in terms of competition with food uses). According to this, it would be given and added value to a residue. But after analyzing the


22


results of the environmental assessment, it is necessary the development of techniques for improving existing processes aiming to reduce emissions into the environment.

CONCLUSION The large technological development that presents the production of ethanol from cassava has been presented as an alternative for its production in Colombia, because its environmental impact is lower than the case when sugarcane bagasse is used as feedstock. The reason of this difference is the pretreatment and detoxification stages involved in sugarcane bagasse processing that produces a huge amount of wastes. On the other hand, the high energy and economic requirements for the production of fuel ethanol from sugarcane bagasse evidences the preference for first generation raw materials (food crops). Another uses of lignocellulosic biomass can be considered to produce different value added products. The previous statement considers that lignocellulosic biomass is a source of sugars, protein, oils and phenolic compounds. However, it is necessary to develop more sustainable processes that take advantage of these compounds. In this sense, more research related to the breakdown of the internal structure of this type of materials, avoiding the increase of the production costs and environmental impacts, is necessary.

ACKNOWLEDGMENTS The authors express their acknowledgments to project “Development of modular smallscale integrated biorefineries to produce an optimal range of bioproducts from a variety of rural agricultural and agroindustrial residues/wastes with a minimum consumptions of fossil energy - SMIBIO” from ERANET LAC 2015.

Conflict of Interest The authors confirm that this chapter has not conflict of interest.

REFERENCES [1]

[2]

[3]

The Statics Portal, “Global ethanol production for fuel use from 2000 to 2015 (in million cubic meters,” Statista, 2016. [Online]. Available: http://www.statista.com/ statistics/274142/global-ethanol-production-since-2000/. [Accessed: 01-Jul-2016]. Ó. J. Sánchez and C. A. Cardona, “Conceptual design of cost-effective and environmentally-friendly configurations for fuel ethanol production from sugarcane by knowledge-based process synthesis,” Bioresour. Technol., vol. 104, pp. 305–314, 2012. M. Balat, H. Balat, and C. Öz, “Progress in bioethanol processing,” Prog. Energy Combust. Sci., vol. 34, no. 5, pp. 551–573, 2008.


Comparison of Cassava and Sugarcane Bagasse … [4]

[5]

[6] [7]

[8]

[9]

[10] [11]

[12]

[13]

[14]

[15] [16]

[17]

[18]

23

R. Suarez-Bertoa, A. A. Zardini, H. Keuken, and C. Astorga, “Impact of ethanol containing gasoline blends on emissions from a flex-fuel vehicle tested over the Worldwide Harmonized Light duty Test Cycle (WLTC),” Fuel, vol. 143, pp. 173–182, 2015. British Petroleum, “BP Statistical Review of World Energy. Fuel ethanol Production,” Knoema, 2016. [Online]. Available: https://knoema.com/BPWES2016/bp-statisticalreview-of-world-energy-2016-main-indicators. [Accessed: 01-Jul-2016]. Renewable Fules Association, “Fueling a high octane future.” pp. 1–40, 2016. O. J. Sánchez, C. A. Cardona, and D. L. Sánchez, “Análisis de ciclo de vida y su aplicación a la producción de bioetanol: Una aproximación cualitativa,” Rev. Univ. EAFIT, vol. 43, no. 146, pp. 59–79, 2012. J. A. Quintero, M. I. Montoya, O. J. Sánchez, O. H. Giraldo, and C. A. Cardona, “Fuel ethanol production from sugarcane and corn: Comparative analysis for a Colombian case,” Energy, vol. 33, no. 3, pp. 385–399, 2008. C. A. Cardona Alzate and O. J. Sanchez Toro, “Energy consumption analysis of integrated flowsheets for production of fuel ethanol from lignocellulosic biomass,” Energy, vol. 31, no. 13, pp. 2111–2123, 2006. C. A. Cardona, Ó. J. Sánchez, and L. F. Gutiérrez, Process Synthesis for Fuel Ethanol Production, vol. 2010, no. 10. United States: Taylor & Francis Group, 2010. N. K. Mekala, R. Potumarthi, R. R. Baadhe, and V. K. Gupta, “Current Bioenergy Researches: Strengths and Future Challenges,” in Bioenergy Research: Advances and Applications, V. K. Gupta, M. G. Tuohy, C. P. Kubicek, J. Saddler, and F. Xu, Eds. Great Britain: Elsevier B.V., 2014, pp. 1–21. A. Duarte Castillo and W. A. Sarache Castro, “La cadena agroindustrial de Biocombustibles: sus particularidades en el caso Colombian,” in Logística y Cadenas de Abastecimiento Agroindustrial, 1st ed., C. E. Orrego Alzate and G. Hernández Pérez, Eds. Manizales, Colombia: Universidad Nacional de Colombia - Sede Manizales, 2012, pp. 83–106. S. I. Mussatto, G. Dragone, P. M. R. Guimaraes, J. P. A. Silva, L. M. Carneiro, I. C. Roberto, A. Vicente, L. Domingues, and J. A. Teixeira, “Technological trends, global market, and challenges of bio-ethanol production,” Biotechnol. Adv., vol. 28, no. 6, pp. 817–830, 2010. P. Alvira, E. Tomás-Pejó, M. Ballesteros, and M. J. Negro, “Pretreatment technologies for an efficient bioethanol production process based on enzymatic hydrolysis: A review,” Bioresour. Technol., vol. 101, no. 13, pp. 4851–4861, 2010. M. Balat and H. Balat, “Recent trends in global production and utilization of bioethanol fuel,” Appl. Energy, vol. 86, no. 11, pp. 2273–2282, 2009. N. Patni, S. G. Pillai, and A. H. Dwivedi, “Wheat as a promising substitute of corn for bioethanol production,” Procedia Eng., vol. 51, no. NUiCONE 2012, pp. 355–362, 2013. M. Enguídanos, A. Soria, B. Kavalov, and P. Jensen, “Techno-economic analysis of Bio-alcohol production in the EU: a short summary for decision makers,” Eur. Comm., no. May, p. 9; 27, 2002. E. Poitrat, “The potential of liquid biofuel in France,” J. Chem. Inf. Model., vol. 16, pp. 1084–1089, 1999.


24


[19] O. J. Sánchez, C. A. Cardona, and I. C. Paz Astudillo, “Fuel ethanol from sugar cane and starch,” in Renewable Fuels Developments in Bioethanol and Biodiesel Production, 1st ed., C. A. Cardona Alzate and J.-S. Lee, Eds. Manizales, Colombia: Universidad Nacional de Colombia - Sede Manizales, 2008, pp. 35–55. [20] T. Botha and H. von Blottnitz, “A comparison of the environmental benefits of bagasse-derived electricity and fuel ethanol on a life-cycle basis,” Energy Policy, vol. 34, no. 17, pp. 2654–2661, 2006. [21] C. A. Cardona Alzate, J. A. Posada Duque, and J. A. Quintero Suarez, “Bagazo de Caña: Uso Actual y Potenciales Aplicaciones,” in Aprovechamiento de subproductos y residuos agroindustriales: Glicerina y Lignocelulósicos, 1st ed., Manizales, Colombia: Universidad Nacional de Colombia - Sede Manizales, 2010, pp. 137–169. [22] A. Bansal, P. Illukpitiya, S. P. Singh, and F. Tegegne, “Economic competitiveness of ethanol production from cellulosic feedstock in tennessee,” Renew. Energy, vol. 59, pp. 53–57, 2013. [23] C. A. Cardona, C. E. Orrego, and I. C. Paz, “The Potential for Production of Bioethanol and Bioplastics from Potato Starch in Colombia,” Fruit, Veg. Cereal Sci. Biotechnol., pp. 102–114, 2009. [24] B. Flach, S. Lieberz, M. Rondon, B. Williams, and C. Teiken, “GAIN Report: EU-28 Biofuels Annual 2015,” 2015. [25] Food and Agriculture Organization of the United Nations (FAO), “FAOSTAT,” 2014. [Online]. Available: http://faostat3.fao.org/browse/Q/QC/E. [Accessed: 01-Jul-2016]. [26] S. Barros, “GAIN Report: Brazil Biofuels Annual 2015,” 2015. [27] A. Aradhey, “GAIN Report: India Biofuels Annual 2015,” 2015. [28] K. Joseph, “GAIN Report: Argentina Biofuels Annual 2015,” 2015. [29] J. Moncada, L. G. Matallana, and C. A. Cardona, “Selection of process pathways for biorefinery design using optimization tools: A colombian case for conversion of sugarcane bagasse to ethanol, poly-3-hydroxybutyrate (PHB), and energy,” Ind. Eng. Chem. Res., vol. 52, no. 11, pp. 4132–4145, 2013. [30] J. A. Quintero, J. Moncada, and C. A. Cardona, “Techno-economic analysis of bioethanol production from lignocellulosic residues in Colombia: a process simulation approach,” Bioresour. Technol., vol. 139, pp. 300–7, Jul. 2013. [31] Asociación de Cultivadores de Caña de Azucar de Colombia (Asocaña), “Balance azucarero colombian Asocaña 2000-2016 (TONELADAS).” [Online]. Available: http://www.asocana.com.co/modules/documentos/5528.aspx. [Accessed: 22-Jul-2016]. [32] A. Anderson Sprecher and J. Ji, “GAIN Report: China Biofuels Annual 2015,” 2015. [33] S. Preechajarn and P. Prasertsri, “GAIN Report: Thailand Biofuels Annual 2015,” 2015. [34] V. A. Vaclavik, “Almidones en los alimentos,” in Fundamentos de ciencia de los alimentos, Spain: Acribia S.A., 2002, pp. 45–61. [35] D. Dessureault, “GAIN Repor: Canada Biofuels Annual 2014,” 2014. [36] A. Kosugi, A. Kondo, M. Ueda, Y. Murata, P. Vaithanomsat, W. Thanapase, T. Arai, and Y. Mori, “Production of ethanol from cassava pulp via fermentation with a surfaceengineered yeast strain displaying glucoamylase,” Renew. Energy, vol. 34, no. 5, pp. 1354–1358, 2009.



25

[37] F. Scott, J. Quintero, M. Morales, R. Conejeros, C. Cardona, and G. Aroca, “Process design and sustainability in the production of bioethanol from lignocellulosic materials,” Electron. J. Biotechnol., vol. 16, no. 3, pp. 1–16, 2013. [38] J. A. Quintero and C. A. Cardona, “Process simulation of fuel ethanol production from lignocellulosics using aspen plus,” Ind. Eng. Chem. Res., vol. 50, no. 10, pp. 6205– 6212, 2011. [39] A. Koopmans and J. Koppejan, “Agricultural and forest residues - Generation, utilization and availability,” Reg. Consult. Mod. Appl. Biomass Energy, pp. 6–10, 1997. [40] European Biofuels Technology Platform, “Cellulosic Ethanol (CE).” [Online]. Available: http://biofuelstp.eu/cellulosic-ethanol.html#inbicon. [Accessed: 01-Jul2016]. [41] T. R. Brown and R. C. Brown, “A review of cellulosic biofuel commercial-scale projects in the United States,” Biofuels, Bioprod. Biorefining, vol. 7, no. 3, pp. 235– 245, 2013. [42] R. Janssen, A. F. Turhollow, D. Rutz, and R. Mergner, “Production facilities for second-generation biofuels in the USA and the EU - current status and future perspectives,” Biofuels, Bioprod. Biorefining, vol. 7, no. 6, pp. 647–665, 2013. [43] M. Galbe and G. Zacchi, “Pretreatment: The key to efficient utilization of lignocellulosic materials,” Biomass and Bioenergy, vol. 46, pp. 70–78, 2012. [44] BETARENEWABLES, “Proesa,” 2016. [Online]. Available: http://www. betarenewables.com/proesa/what-is. [Accessed: 01-Jul-2016]. [45] S. Francois Bazzana, C. E. Camp, B. Curt Fox, S. Schiffino, and K. Dumont Wing, “Ammonia pretreatment of biomass for improved inhibitor profile,” WO 2011/046818 A2, 2011. [46] Office of Energy Efficiency & Renewable Energy, “Integrated Biorefineries.” [Online]. Available: http://energy.gov/eere/bioenergy/integrated-biorefineries. [Accessed: 01-Jul2016]. [47] American Process, “GreenPower+.” [Online]. Available: http://www. americanprocess. com/GreenPowerPlus.aspx. [Accessed: 01-Jul-2016]. [48] L. Ward, “2015 DOE Bioenergy Technologies Office(BETO) IBR Project Peer Review,” POET-DSM Advanced Biofuels, 2015. [Online]. Available: http://www. energy.gov/sites/prod/files/2015/04/f22/demonstration_market_transformation_ward_3 433.pdf. [Accessed: 01-Jul-2016]. [49] Edeniq, “Pilot plants.” [Online]. Available: http://www.edeniq.com/pilot-plants/. [Accessed: 01-Jul-2016]. [50] GranBio, “Bioflex I.” [Online]. Available: http://www.granbio.com. br/en/conteudos/ biofuels/. [Accessed: 01-Jul-2016]. [51] Enerkem, “Exclusive thermochemical process,” 2015. [Online]. Available: http://enerkem.com/about-us/technology/. [Accessed: 01-Jul-2016]. [52] J. L. Gaddy, D. K. Arora, C.-W. Ko, J. R. Phillips, R. Basu, C. V. Wilkstrom, and E. C. Clausen, “Methods for increasing the production of ethanol from microbial fermentation,” US 8 642 302 B2, 2014. [53] P. Reinikainen, T. Suortti, J. Olkku, Y. Mälkki, and P. Linko, “Extrusion Cooking in Enzymatic Liquefaction of Wheat Starch,” Starch - Stärke, vol. 38, no. 1, pp. 20–26, 1986.


26


[54] C. A. Cardona Alzate, O. J. Sánchez Toro, J. A. Ramírez Arango, and L. E. Alzate Ramírez, “Biodegradación de residuos orgánicos de plazas de mercado,” Rev. Colomb. Biotecnol., vol. VI, no. 2, pp. 78–89, 2004. [55] Y. Sun and J. Cheng, “Hydrolysis of lignocellulosic materials for ethanol production : a review,” Bioresour. Technol., vol. 83, no. 1, pp. 1–11, 2002. [56] P. Kumar, P. Kumar, D. M. Barrett, D. M. Barrett, M. J. Delwiche, M. J. Delwiche, P. Stroeve, and P. Stroeve, “Methods for Pretreatment of Lignocellulosic Biomass for Efficient Hydrolysis and Biofuel Production,” Ind. Eng. Chem. (Analytical Ed., pp. 3713–3729, 2009. [57] P. Atthasampunna, P. Somchai, A. Eur-aree, and S. Artjariyasripong, “Production of fuel ethanol from cassava,” MIRCEN J. Appl. Microbiol. Biotechnol., vol. 3, no. 2, pp. 135–142, 1987. [58] M. Bhattacharya and M. A. Hanna, “Kinetics of Starch Gelatinization During Extrusion Cooking,” J. Food Sci., vol. 52, no. 3, pp. 764–766, May 1987. [59] P. Taggart, “Starch as an ingredient: manufacture and applications,” in Starch in Food, A.-C. Eliasson, Ed. 2004, pp. 363–392. [60] P. V Aiyer, “Amylases and their applications,” African J. Biotechnol., vol. 4, no. 13, pp. 1525–1529, 2005. [61] P. M. de Souza and P. de Oliveira Magalhães, “Application of microbial α-amylase in industry - A review.,” Braz. J. Microbiol., vol. 41, no. 4, pp. 850–61, Oct. 2010. [62] S. Pervez, A. Aman, S. Iqbal, N. Siddiqui, and S. Ul Qader, “Saccharification and liquefaction of cassava starch: an alternative source for the production of bioethanol using amylolytic enzymes by double fermentation process,” BMC Biotechnol., vol. 14, no. 1, p. 49, 2014. [63] C. A. Cardona, J. A. Quintero, and I. C. Paz, “Production of bioethanol from sugarcane bagasse: Status and perspectives.,” Bioresour. Technol., vol. 101, no. 13, pp. 4754–66, Jul. 2010. [64] D. P. Maurya, A. Singla, and S. Negi, “An overview of key pretreatment processes for biological conversion of lignocellulosic biomass to bioethanol,” 3 Biotech, vol. 3, no. 5, pp. 415–431, 2013. [65] N. Mosier, C. Wyman, B. Dale, R. Elander, Y. Y. Lee, M. Holtzapple, and M. Ladisch, “Features of promising technologies for pretreatment of lignocellulosic biomass,” Bioresour. Technol., vol. 96, no. 6, pp. 673–686, 2005. [66] P. Kumar, D. M. Barrett, M. J. Delwiche, and P. Stroeve, “Methods for pretreatment of lignocellulosic biomass for efficient hydrolysis and biofuel production,” Ind. Eng. Chem. Res., vol. 48, no. 8, pp. 3713–3729, 2009. [67] Y. H. Jung and K. H. Kim, “Acidic Pretreatment,” in Pretreatment of Biomass, A. Pandey, S. Negi, P. Binod, and C. Larroche, Eds. Elsevier, 2014, pp. 27–50. [68] A. Das, C. Mondal, and S. Roy, “Pretreatment Methods of Ligno - Cellulosic Biomass: A Review,” J. Eng. Sci. Technol. Rev., vol. 8, no. 5, pp. 141–165, 2015. [69] V. B. Agbor, N. Cicek, R. Sparling, A. Berlin, and D. B. Levin, “Biomass pretreatment: Fundamentals toward application,” Biotechnol. Adv., vol. 29, no. 6, pp. 675–685, 2011. [70] M. Saritha, A. Arora, and Lata, “Biological Pretreatment of Lignocellulosic Substrates for Enhanced Delignification and Enzymatic Digestibility,” Indian J Microbiol., vol. 52, no. 2, pp. 122–130, 2012.



27

[71] D. Pinaki, W. Lhakpa, and S. Joginder, “Simultaneous Saccharification and Fermentation (SSF), An Efficient Process for Bio-Ethanol Production: An overview,” BIOCIENCES Biotechnol. Res. ASIA, vol. 12, no. 1, pp. 1–14, 2015. [72] F. Talebnia, D. Karakashev, and I. Angelidaki, “Production of bioethanol from wheat straw: An overview on pretreatment, hydrolysis and fermentation,” Bioresour. Technol., vol. 101, no. 13, pp. 4744–4753, 2010. [73] D. Dahnum, S. O. Tasum, E. Triwahyuni, M. Nurdin, and H. Abimanyu, “Comparison of SHF and SSF processes using enzyme and dry yeast for optimization of bioethanol production from empty fruit bunch,” Energy Procedia, vol. 68, pp. 107–116, 2015. [74] J. H. Lee, R. J. Pagan, and P. L. Rogers, “Continuous simultaneous saccharification and fermentation of starch using Zymomonas mobilis.,” Biotechnol. Bioeng., vol. 25, no. 3, pp. 659–669, 1983. [75] A. Q. Julian, A. C. Carlos, F. Erika, M. Jonathan, and C. H. Juan, “Techno-economic analysis of fuel ethanol production from cassava in Africa: The case of Tanzania,” African J. Biotechnol., vol. 14, no. 45, pp. 3082–3092, 2015. [76] J. Aristizábal and T. Sánchez, “Guía técnica para producción y análisis de almidón de yuca,” Food and Agriculture Organization of the United Nations (FAO), vol. 163. Roma, pp. 36–39, 2007. [77] J. A. Quintero, M. I. Montoya, Ó. J. Sanchez, and C. A. Cardona, “Evaluation of Fuel Ethanol Dehydration Through Process Simulation,” Fac. Ciencias Agropecu., vol. 5, no. 2, pp. 72–83, 2007. [78] J. Moncada, V. Hernández, Y. Chacón, R. Betancourt, and C. A. Cardona, “Citrus Based Biorefineries,” in Citrus Fruits. Production, Consumption and Health Benefits, D. Simmons, Ed. Nova Publishers, 2015, pp. 1–26. [79] L. V. Daza Serna, J. C. Solarte Toro, S. Serna Loaiza, Y. Chacón Perez, and C. A. Cardona Alzate, “Agricultural Waste Management Through Energy Producing Biorefineries: The Colombian Case,” Waste and Biomass Valorization, pp. 1–10, Jun. 2016. [80] S. Sun, S. Sun, X. Cao, and R. Sun, “The role of pretreatment in improving the enzymatic hydrolysis of lignocellulosic materials,” Bioresour. Technol., vol. 199, pp. 49–58, 2016. [81] A. Esteghlalian, A. G. Hashimoto, J. J. Fenske, and M. H. Penner, “Modeling and optimization of the dilute-sulfuric-acid pretreatment of corn stover, poplar and switchgrass,” Bioresour. Technol., vol. 59, no. 2–3, pp. 129–136, 1997. [82] L. H. da Silva Martins, S. C. Rabelo, and A. C. da Costa, “Effects of the pretreatment method on high solids enzymatic hydrolysis and ethanol fermentation of the cellulosic fraction of sugarcane bagasse,” Bioresour. Technol., vol. 191, pp. 312–321, 2015. [83] X. Guo, A. Cavka, L. J. Jönsson, and F. Hong, “Comparison of methods for detoxification of spruce hydrolysate for bacterial cellulose production,” Microb. Cell Fact., vol. 12, p. 93, 2013. [84] R. Purwadi, C. Niklasson, and M. J. Taherzadeh, “Kinetic study of detoxification of dilute-acid hydrolyzates by Ca(OH)2,” J. Biotechnol., vol. 114, no. 1–2, pp. 187–198, 2004. [85] N. Leksawasdi, E. L. Joachimsthal, and P. L. Rogers, “Mathematical modelling of ethanol production from glucose/xylose mixtures by recombinant Zymomonas mobilis,” Biotechnol. Lett., vol. 23, pp. 1087–1093, 2001.


28


[86] R. J. Wooley and V. Putsche, “NREL/MP-425-20685 Development of an Aspen Pus property database for biofuels components,” National Renewable Energy Laboratory, 1996. [87] J.-L. Wertz and O. Bédué, “Features of First Generation Biorefineries,” in Lignocellulosic Biorefineries, Taylor & Francis Group, 2013, p. 13–19; 83. [88] J. A. Dávila, V. Hernández, E. Castro, and C. A. Cardona, “Economic and environmental assessment of syrup production. Colombian case,” Bioresour. Technol., vol. 161, pp. 84–90, 2014. [89] S. H. Duque, C. A. Cardona, and J. Moncada, “Techno-Economic and Environmental Analysis of Ethanol Production from 10 Agroindustrial Residues in Colombia,” Energy Fuels, vol. 29, no. 2, pp. 775–783, 2015. [90] D. Young, R. Scharp, and H. Cabezas, “The waste reduction (WAR) algorithm: environmental impacts, energy consumption, and engineering economics,” Waste Manag., vol. 20, no. 8, pp. 605–615, Dec. 2000. [91] C. A. Cardona, Ó. J. Sanchez, M. I. Montoya, J. A. Quintero, and L. F. Gutierrez, “Energy and environmental impact of using lignocellulosic biomass or starch in bioethanol production,” in Renewable Fuels Developments in Bioethanol and Biodiesel Production, 1st ed., C. A. Cardona Alzate and J.-S. Lee, Eds. Manizales, Colombia: Universidad Nacional de Colombia - Sede Manizales, 2008, pp. 63–75. [92] A. Pandey, C. R. Soccol, P. Nigam, V. T. Soccol, L. P. S. Vandenberghe, and R. Mohan, “Biotechnological potential of agro-industrial residues. II: cassava bagasse.,” Bioresour. Technol. Technol., vol. 74, pp. 81–87, 2000. [93] K. Sato, K. Nakamura, and S. Sato, “Solid-State Ethanol Fermentation by Means of Inert-Gas Circulation,” Biotechnol. Bioeng., vol. 27, no. 9, pp. 1312–1319, 1985. [94] V. Aristizábal M., Á. Gómez P., and C. A. Cardona A., “Biorefineries based on coffee cut-stems and sugarcane bagasse: Furan-based compounds and alkanes as interesting products,” Bioresour. Technol., vol. 196, pp. 480–489, 2015. [95] A. Gupta and J. P. Verma, “Sustainable bio-ethanol production from agro-residues: A review,” Renew. Sustain. Energy Rev., vol. 41, pp. 550–567, 2015.




Chapter 2

CASSAVA PRODUCTION AND ITS ECONOMIC POTENTIALS IN SUB-SAHARA AFRICA: A REVIEW Emmanuel Ukaobasi Mbah* Department of Agronomy, Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria

ABSTRACT Cassava (Manihot esculenta Crantz), which originated from tropical America and today a dietary staple to most people living in Sub-Sahara Africa is a perennial woody shrub with an edible root, which is rich in carbohydrates, calcium (50 mg 100-g), phosphorus (40 mg 100-g), vitamins B and C, as well as some essential minerals, while its tender leaves serve as a veritable source of lysine rich protein. The roots though poor in protein and other minerals, their nutrient compositions differ depending on the variety and age of the harvested crop, as well as soil conditions, climate, and other environmental factors under which the crop is grown. The stem of cassava is used as planting material and can serve as a standard substrate in mushroom production as well as fuel wood when dried. Cassava is characterized as one of the most drought tolerant crop that is capable of growing on marginal soils. The crop is rarely cultivated as a mono-crop because of its physiological growth habit and duration, which makes it to stand out as an excellent component crop in most intercropping systems. Hence, it is usually intercropped with most vegetables, yam, sweet potato, melon, maize, sorghum, millet, rice, groundnut, sesame, soybean, cowpea and other legumes, as well as plantation crops (such as oil palm, kola, rubber, cocoa, cashew and coffee) among other field crops grown in the tropical regions of the world. Roots of cassava may be due for harvesting between six months and three years (36 months) after planting. Apart from food, cassava root tubers are very versatile, hence its derivatives and qualitative starch are effectively used in a number of products such as foods, confectionery, sweeteners, paper, glues, textiles, plywood, biodegradable products, monosodium glutamate, and pharmaceuticals. Cassava chips and pellets are used in animal feed and alcohol production as well as ethanol and bio-diesels. Crop improvements associated with cassava is tailored on developing genotypes that can effectively correlate the end product with its utilization at the industrial level. The impact of research on cassava development ranging from biotec*

E-mail: [email protected]; Phone: +234 803 460 8421.


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Emmanuel Ukaobasi Mbah breeding, genetics and selection to production, value-chain addition and utilization is immerse, hence, high quality improved cassava varieties which are disease- and pestresistant, low in cyanide content, drought-resistant, early bulking, high starch content, high dry matter content, and high yielding are being cultivated by most farmers in the tropical regions today where cassava thrives. Annual world production of cassava (184 million tonnes) with Nigeria being the leading producer has continued to increase due to the development of improved varieties with high yield, excellent culinary qualities and resistance to pests and diseases among other invaluable properties. In this review therefore, scientific findings by a number of scholars on cassava are discussed with the aim of making the information a veritable tool for researchers in this field.

Keywords: cassava, production, intercropping, genotype, utilization

INTRODUCTION Cassava, which originated from tropical South America, is a perennial woody shrub with an edible root, which today is grown in tropical and subtropical regions of the world where according to Bokang (2001), Ceballos et al. (2006) and Nuwamanya et al. (2009) it provides energy food and serves as a veritable source of food and income for over a billion people (FAO, 2007; Sis, 2013). Cassava, Manihot esculenta is the only one of 98 species in the family of Euphorbiaceae that is widely cultivated for food production. Currently, it is a dietary staple in most countries in Sub Sahara Africa (Hahn and Keyser, 1985; Kawano, 2003; Amani et al., 2005) where it is grown under subsistence farming by small scale farmers because the crop grows well in poor soils and requires limited labour. The crop is well adapted within latitudes 30 °north and south of the equator, at altitudes between sea level and 2,500 meters above sea level, in equatorial climes with rainfalls of 200 mm to 2,700 mm annually. Today it has been given the status of a cultigen with no wild forms of the species being known (Cock, 1986; Hulugalle and Ezumah, 1991; Akoroda, 2005; Mbah and Ogidi, 2012). Cassava root is rich in carbohydrates, calcium, vitamins B and C, and essential minerals. Its nutritional profile indicates 60 – 65, 20 – 31, 1 – 2 per cent moisture, carbohydrate and crude protein contents, respectively and a relatively low amount of vitamins and minerals while starch obtained from the crop contains 70 and 20 per cent amylopectin and amylose substances, respectively. However, nutrient composition differs according to variety and age of the harvested crop, and soil conditions, climate, and other environmental factors during cultivation. In terms of food calories produced per hectare per day, cassava gives food calories that are far more than 250,000, cal-1 hectare-1 day-1 relative to rice and maize with 176,000 and 200,000, cal-1 hectare-1 day-1, respectively (FAO, 2012).

CASSAVA IN INTERCROPPING Intercropping, which is a type of mixed cropping entails the agricultural practice of cultivating two or more crops within a micro-ecological zone at the same time so that the component crops share the same ecological niche thereby enhancing the biological efficiency of the system relative to monocropping (Ofori and Stern, 1987; Adetiloye, 1989; Fininsa,


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1997; Khan and Khaliq, 2004; Mbah and Muoneke, 2007). A number of advantages such as the reduction of weed pressure on the farm (Trenbath, 1993), effective control of soil erosion through appropriate canopy coverage and good root development (Alves, 2002), improved economical and environmental performance of the production system, (Hauggaard-Nielsen et al., 2001, Adjei-Nsiah, et al., 2007), reduction of excessive leaching of nitrate (Corre-Hellou, 2005) and improved crop yield stability (Ngendahayo. and Dixon, 2001; Njoku et al., 2009) among others can be adduced to positive intercrop association. According to Willey (1979), Mead and Willey (1980), Beeching et al. (2000), Mbah and Muoneke (2007) as well as Adrien et al. (2012) cassava fits with a great number of other crops in various cropping systems in the tropics and subtropics. Cassava is a long duration crop that matures between 6 and 36 months after planting, hence features prominently in different types of intercropping systems involving cereals, legumes, vegetables and even plantation crops such as maize, rice, groundnut melon, oil palm, and coffee coconut under a plant population that oscillates between 8,000 and 16,000 plants per hectare (Trenbath, 1993; Mbah et al., 2003).

PRODUCTION TECHNIQUES Nigeria is the world's largest producer of cassava while Thailand is the largest exporting country of dried cassava root tubers followed by Vietnam (FAO, 2012). In terms of productivity, cassava farms in India are the highest ranking with an average fresh root tuber yield of 34.8 tonnes per hectare. However, productivity depends on a number of factors such quality stem cuttings employed during planting because cassava stem cuttings are not only bulky but are highly perishable depending on cultivar such that they dry up within a couple of days after harvesting if not properly preserved under shade in a slightly humid environment to prevent desiccation (Lozano et al., 1977; Eke-Okoro et al., 2005).

SELECTION AND PREPARATION OF PLANTING MATERIAL Cassava is normally planted using stem cuttings obtained from a mother plant that is 8 12 months old. Eze and Ugwuoke (2009) reported that cassava stakes derived from the middle and lower (20 cm above the soil level) parts of the stem exhibit significant (P < 0.05) higher germination rates compared to those derived from the upper part of the stem and those obtained from the portion below 20 cm from the soil surface. Longer matured cassava stakes (15 - 20 cm) obtained from the middle portions of mature stem exhibit higher germination percentage compared to shorter stakes of 5 - 10 cm length (Cock et al., 1986; Eke-Okoro, et al., 2005). According to Ezulike, et al. (1993), Fauquet and Farguette (1990), Makumbi-kidza et al. (2000), Egesi et al. (2004) as well as Echendu (2006) the selection of healthy, diseasefree and pest-free stakes is essential to ensure higher productivity. Cassava planting can be done manually or mechanically in moist, well prepared ridges or mounds or even flat in friable loose soils. It is achieved by burying the lower half of the stake (cutting) in a slanted position (45), or in an upright position (90) or where the soils are too shallow and friable cuttings are laid flat and covered with 2 - 3 cm soil. Good observation of


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Emmanuel Ukaobasi Mbah

the polarity of the cutting is very important to ensure even and successful establishment of a cassava farm (Lozano et al., 1977; Alves, 2002; Imo, 2006; Uguru, 2011). Typical plant spacing for cassava is 1 m by 1 m to give a plant population of 10,000 plants per hectare. The crop can also be planted at 90 cm by 100 cm, 80 cm by 100 cm.

CULTIVARS Currently a wide range of cassava cultivars have been developed since the on set of national and international breeding programmes and most of the released clones are highly resistant to many of the major diseases and pests of the crop. The cultivars exhibit strong variations not only in fresh root tuber yield but also in root diameter and length, disease and pest resistance levels, bulking rate, maturity period, being able to adapt to different environmental conditions, levels of dry matter content, cooking quality and garrification, as well as colour of root flesh among other traits (Braima et al., 2000; Okonkwo, 2002; Githunguri et al., 2004, El-Sharkawy 2006; Ekwe et al., 2008). In terms of physiological growth, cassava is a short day plant, hence tuberization is usually under photoperiodic influence such that when the day length is greater than 10 to 12 hours, root tuber formation is greatly impaired and yields are invariably low. However, shoot weight ratio value is higher. In contrast, when the crop is exposed to short day lengths, root tuber yield is enhanced (Imo, 1995).

WEEDING Cassava is characterized by a relatively slow crop growth rate during the first three months after planting, hence, could be highly susceptible to the menace of weeds, which could lead to low root tuber yield. The efficacy of weeds in cassava farms depend on their growth rate or vigour, degree of density and growth period of weeds relative to the cassava crop (Akinpelu, et al., 2006). Akobundu (1980) as well as Liebman and Dyck (1993) reported that critical period for weed control in cassava is 12 to 16 weeks after planting. Manual weeding with hoe or the use of appropriate herbicides may be employed to control weeds in cassava farms effectively.

SOIL REQUIREMENTS AND FERTILIZER APPLICATION The crop requires well-drained, light to medium soils with soil pH in water between 4.5 and 7.5. The crop is well adapted to acidic soils with high levels of exchangeable aluminium (Al), low levels of available phosphorus (P) and relatively high levels of potassium (K). Cassava responds well to P and K fertilization. The crops also benefits from the scavenging activities of vesicular-arbuscular (VA) mycorrhizae, which tap phosphorus in the soil and ramify it around the roots of cassava for effective utilization (Sieverding and Leihner, 1984). A number of Studies on fertilizer requirements of cassava by Howeler, (1981), IITA (1985), Carsky and Toukourou (2005), Aderi et al. (2010) as well as Byju et al. (2012)



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revealed that insufficient and unbalanced fertiliser use widens cassava yield gaps in terms of productivity. Furthermore, Njoku et al. (2009), Sayre et al. (2011) and Ezui et al. (2016) in their studies on fertiliser requirements for balanced nutrition of cassava submitted that potassium (K) is the most limiting nutrient relative to nitrogen (N) and phosphorus (P) to achieve fresh storage root yields of up to 8 Mg dry matter ha−1 in the West African sub region. Therefore, for enhanced nutrient use efficiency in both sole and intercropping systems, appropriate fertiliser recommendations based on balanced nutrition may lead to a reduction in cassava yield gaps. Depending on soil analysis, soils in humid tropics that are acidic require liming to the tune of 500 to 1,000 kg ha-1 and 400 to 600 kg ha-1 of NPK fertilizer in cassava cultivation (Eke-Okoro, 2000).

HARVESTING Harvesting of cassava involves serious manual operations, which entails cutting the upper portion of the stem with the leaves at a height of 30 to 50 cm from the ground level and then with the aid of the stump the roots are carefully pulled out of the ground. Harvested root tubers are then neatly chucked out from the attachment base of the plant with the sharp machete. Cassava harvesting demands great care as to minimize damage to the roots and enhance the shelf life of the root tubers. According to Maini et al. (1977), Ashoka et al. (1984), Ikpi et al. (1986) and Njoku, et al.(2014a), root tubers of cassava mature and can be harvested between the age of 8 and 36 months after planting (MAP) depending on felt need, variety, insect pest attack, environmental factors among other factors. However, the appropriate harvesting age is 12 MAP.

ECONOMIC IMPORTANCE OF CASSAVA AND ITS POTENTIAL USES The economic value for cassava products is the dry matter content which is the chemical potential of the crop and reflects the true biological yield of the crop (IITA, 1985) and according to Hahn et al. (1979), Lain (1985) and Kawano et al. (1987) dry matter content is controlled by polygenic additive factor as well as other factors such as age of the plant, variety, cropping season, location and efficiency of the canopy to intercept solar radiation. Barima et al. (2000) in his studies reported that dry matter content of cassava varies depending on accessions and ranges from 17 to 47 per cent. However, dry matter content above 30 per cent is considered high. Studies by Hahn et al. (1979), Ntawuruhunga et al. (1998) and Ngendahayo and Dixon (2001) indicated that optimal growth and productivity of cassava is related to its harvest index and the desirable indices range from 0.5 to 0.7. Potential fresh root tuber yield of cassava under favourable controlled environment can reach 90 t ha-1 while average yields from subsistence agricultural systems are about 10.0 t ha-1.

CASSAVA PROCESSING


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Cultivars of cassava are generally categorised as either sweet or bitter, signifying levels of toxic cyanogenic glucosides, linamarin and lotaustralin present in them (Okpara et al., 2014). Linamarase, a naturally occurring enzyme acts on the glucosides when the cells are ruptured and convert them to hydrogen cyanide. All parts of the plant contain this toxic substance. However, the leaves have the highest concentrations while the root peels (exoderma) have higher concentrations than the interior fleshy part (Aregheore and Agunbiade, 1991; White, 1998; Nuwamanya, et al., 2009). Sweet cassava cultivars can produce as little as 20 milligrams of cyanide (CN) per kilogram of fresh roots, while bitter cultivars may produce as much as 1 g kg-1 of fresh roots. Note, cassava grown under drought conditions, are highly prone to have more of these toxins in their roots. Fresh root tubers of cassava undergo post-harvest physiological deterioration (Njoku, et al., 2014b), which involves the activities of coumaric acids that initiate within 15 minutes after damage, and continues until the entire tuber is oxidized and blackened within 24 to 72 hours after harvesting. Thereafter, the roots are rendered completely unpalatable and useless. This implies that cassava root tubers immediately after harvesting require appropriate processing such as grating, sun drying, frying and soaking in water to ferment aimed at reducing the cyanide content in the enlarged roots before it can be fit for human consumption. Fresh cassava roots are usually peeled, grated and washed with water to extract the starch and can be used to make breads, crackers, pasta and pearls of tapioca while unpeeled roots can be grated and dried for use as animal feed. Also, cassava leaves can be used to fortify the level of protein content in animal feed. In industrial settings, cassava can be employed in the manufacture of products such as paper-making, textiles, adhesives, high fructose syrup and alcohol. Dried roots can be milled into flour and used for baking breads and other confectionaries (Nuwamanya, et al., 2009; Njoku, et al., 2014b). Apart from food, cassava is very versatile and its derivatives and starch are applicable in many types of products such as foods, confectionery, sweeteners, glues, plywood, textiles, paper, biodegradable products, monosodium glutamate, and drugs. Cassava chips and pellets are used in animal feed and alcohol production. Cassava leaves can be used to make soup or as feed for livestock, the stems can be used as planting materials, for mushroom production or as fuel wood while the root tubers can be cooked and eaten straight or processed (FAO, 2007).

SOME CRITICAL ECONOMIC IMPORTANCE OF CASSAVA Cassava-Based Ethanol (Biofuel) Current programs in a number of countries have shown significant research across board to assess the use of cassava as a veritable source of ethanol, biofuel or gasohol hence, cassava chips are gradually becoming a major source for the production. This is so because a ton of fresh root tuber of cassava yields about 150 litres of ethanol higher relative to other biological sources.



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Animal Feed Cassava tubers and hay (dried cassava leaves) are used as animal feed. Cassava hay is prepared by harvesting juvenile cassava plants that are about three to four months (when the plant height is about 30 – 45 cm from the surface of the ground). The plants are then sundried for one to two days until it has final dry matter content of less than 85%. Nutritionally, cassava hay contains high protein (20 – 27% crude protein) and condensed tannins (1.5 – 4% CP). It is valued as a good roughage source for ruminants such as goats, sheep, dairy or beef cattle and even buffalo. It can be fed to the animals directly or as a protein source in concentrate mixtures. Also, cassava chips, pellets, root meal, ensilage and cassava foliage flour serve as veritable livestock feeds.

Industrial Uses of Cassava Cassava comes in handy as raw material in a number of industries and can be used to make a number of products such as laundry starch, gums, glues, yeast, binders, commercial caramel, malt beer, pharmaceutical products- syrup, vitamins, monosodium glutamate, dextrins, butyl alcohol, proply alcohol, dextrose, acetone, glucose syrup, among others.

Cassava Confectionaries High quality cassava flour (HQCF) can be used in the production of bread and cake as well as other secondary products such as biscuits, pies, croquette and noodles.

SOME PESTS, DISEASES AND CONSTRAINTS OF CASSAVA Two principal pests affecting cassava production in Sub-Sahara Africa are the cassava green mite and the variegated grasshopper while major diseases are cassava mosaic disease (CMD), cassava bacterial blight (CBB), cassava anthracnose disease (CAD), and root rot (Trenbath, 1993; Echendu, 2006). Pests, diseases and poor management practices combined are responsible for crop yield losses as high as 50 per cent. Series of research studies by scientists in International Institute for Tropical Agriculture (IITA), Ibadan, Nigeria and National Root Crops Research Institute, (NRCRI) Umudike, Nigeria have led to the development and release of a number of improved cassava varieties that are not only disease- and pest-resistant, low in cyanide content, drought-resistant but are also early maturing and high yielding. In general, disease-resistant varieties give sustainable fresh root tuber yields of about 50% more than local varieties. Also, according to Makumbikidza et al. (2009), a wide range of plant parasitic nematodes have been reported associated with cassava of which Scutellonema spp. and Meloidogyne spp., have been identified to have greater economic impact on the crop in the field.


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CONCLUSION Cassava has a major role to play in the industrial development of Nigeria as well as other developing countries in tropical and subtropical regions of the world. However, the current average yield level is low relative to what is obtainable under standard management practices due to use of local or low yield potential varieties, poor soil fertility and nutrient management, pests and diseases effect, poor extension services, among others. Therefore, a good understanding of appropriate management practices coupled with the adoption of improved variety that would act as a enzyme in cassava production chain would boost fresh root tuber yield for better nutrition and enhance industrial development as well as serve as a good source of foreign exchange for the country. As part of the underlying efforts, current research activities centred on a cassava project code-named BioCassava Plus aimed at developing cassava varieties with lower cyanogen glucosides and fortified with vitamin A, iron and protein to help the nutritional status of people living the region is still on course with promising results having made some significant achievements by releasing some pro-vitamin A cassava varieties for multiplication by farmers in the sub-region.

REFERENCES Aderi, O.S., Ndaeyo, N.U. and Edet, U.E. (2010). Growth and yield responses of four cassava morphotypes to low levels of NPK fertilization in humid agroecology of southeastern Nigeria. Nigeria Journal of Agriculture, Food & Environment, 6 (3 & 4):14 - 18. Adetiloye, P.O. (1989). A review of current competition indices and models for formulating component proportions in intercropping in cassava based cropping systems. Research, 11:72 – 90. Adjei-Nsiah, S., Kuyper, T., Leeuwis, C., Abekoe, M., Giller, K. (2007). Evaluating sustainable and profitable cropping sequences with cassava and four legume crops: effects on soil fertility and maize yields in the forest/savannah transitional agroecological zone of Ghana. Field Crops Research, 103, 87–97. Adrien, N.1., Nzola, M.1., Antoine, F.1. and Adrien, M. (2012). Enhancing yield and profitability of cassava in the savannah and forest zones of Democratic Republic of Congo through intercropping with groundnut. Journal of Applied Biosciences, 89:8320 – 8328. Akinpelu, A.O., Ogbonna, M.C., Asumugha, G.N., Ogbe,af.o. and Emehute, J.K.U. (2006). Socio-economic evaluation of improved cassava production (NR 8082) in Umudike. Root Crops Research Division, Annual Report, NRCRI, Umudike, Nigeria. Akobundu, I.O. (1980). Weed Control Strategies For Multiple Cropping Systems Of The Humid And Sub-Humid Tropics. Weeds and their control in the humid and sub-humid tropics. International Institute for Tropical Agriculture (IITA), Ibadan, pp.80 - 101. Akoroda, M.O. (2005). Root Crops, Institute of Agricultural Research, Ngaounudere, Cameroon, pp. 537.



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Alves, A.A.A. (2002). Cassava botany and physiology. In: Hillocks, Thresh, R.J., Bellotti, A.C. (eds.). Cassava Biology, Production and Utilisation. CABI. International Oxford. pp. 67 – 89. Amani, N.G., Kamenan, A., Rolland-Sabate, A. and Colonna, P. (2005). Stability of yam starch gels during processing. African Journal of Biotechnology, 4(1): 94 - 101 Aregheore E.M. and Agunbiade O.O. (1991). "The toxic effects of cassava (Manihot esculenta Crantz) diets on humans: A review. Veterinary Human Toxicology, 33 (3): 274 – 275. Ashoka PV, Nair SV, Kurian, TM (1984). Influence of stages of harvest on the yield and quality of cassava (Manihot esculenta Crantz). Mandraos Agricultural Journal, 71:447 449. Beeching, J.R., Niger, T and Tohman, J. (2000). Post harvest physiological deterioration of cassava. Proceedings of 12th symposium of International Society of Tropical Root Crops held in Tsukuba, Japan, September, pp.10-16. Bokanga M. 2001. Cassava: Post-harvest operations International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria. pp. 220. Braima, J., Neuenschwamder, H., Yaninek, F., Cudjoe, J.P., Echendu, N. and Toko, M. (2000). Pest Control in Cassava farms: IPM Field Guide for Extension Agents. Wordsmiths Printers, Lagos, Nigeria. Pp.36. Byju, G., Nedunchezhiyan, M., Ravindran, C.S., Mithra, V.S.S., Ravi, V. and Naskar, S.K. (2012). Modeling the response of cassava to fertilizers: a site-specific nutrient management approach for greater tuberous root yield. Commun. Soil Science Plant Analysis, 43, 1149 –1162. Carsky, R.J. and Toukourou, M.A. (2005). Identification of nutrients limiting cassava yield Agro-ecosystem, 71, 151 – 162. Ceballos, H., Sanchez, T., Morante, N., Fregene, M., Dufour, D., Smith, A., Denyer, K., Perez, J., Calle, F. and Mestres, C. (2006). Discovery of an Amylose-free starch mutant in cassava (Manihot esculenta Crantz). Journal of Agriculture and Food Chemistry. 55: 7469-7476. Cock, J.H. (1986). Cassava: Its calories can overcome malnutrition. International Center for Tropical Agriculture (CIAT), Cali Colombia. Tropic, 147:30 - 33. Corre-Hellou, G. and Crozat, Y. (2005) Assessment of root system dynamics of species grown in mixtures under field conditions using herbicide injection and N-15 natural abundance methods: A case study with pea, barley and mustard. Plant Soil, 276:177 192. Echendu, T.N.C. (2006). Regional survey of cassava fields to assess cassava green mite pest damage, infestation and the distribution of the predator, T. aripo. National Root Crops Research Institute (NRCRI), Umudike, Nigeria. Annual Report and 2006 Research Proposals. Egesi, C.N., Ogbe, F.O., Dixon, A.G.O., Akoroda, M.O., Ukpabi, U.J., Eke-Okoro, O.N. and Ubalua, A. (2004). Multilocational trials of cassava mosaic disease resistant varieties. NRCRI., Umudike, Nigeria, Annual Report. Eke-Okoro, O.N. (2000). Effects of altitude and NPK fertilizer on photosynthesis efficiency and yield of cassava varieties in Nigeria. Journal of Sustainable agriculture and Environment, 2 (2):165 – 170.


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Eke-Okoro, O.N., Ekwe, K.C. and Nwosu, K.I. (2005). Cassava Stem and Root Production: A Practical Manual, National Root Crops Research Institute, Umudike, 51p. Ekwe, K., Nwachukwu, C.I. and Ekwe, C.C. (2008). Determinants of improved garri processing technologies utilization and marketing profile among rural households in southeastern Nigeria. Nigerian Journal of Rural Sociology, 8(1):1 - 8. El-Sharkawy, M.A. (2006). International research on cassava photosynthesis, productivity, eco-physiology, and responses to environmental stresses in the tropics. Photosynthetica, 44: 481 – 512. Eze, S.C. and Ugwuoke, K.I. (2009). Evaluation of different stem portions of cassava (Manihot esculentus) in the management of its establishment and yield, In: Olojede, A.O., Okoye, B.C., Ekwe, K.C., Chukwu, G.O., Nwachukw, I.N., Alawode, O. (Eds). Proceedings of the 43rd Annual conference of Agricultural Society of Nigeria, held at National Universities Commission Auditorium and RMRDC, Abuja, Nigeria, Tues. 20th – 23rd October, 2009, pp. 120-123. Ezuia, B., Frankeb, A.C., Mandoa, C.A., Ahiabord, B.D.K., Tettehe, F.M., Sogbedjia, J., Janssenb, B.H. and Giller, K.E. (2016). Fertiliser requirements for balanced nutrition of cassava across eight locations in West Africa. Field Crops Research, 185: 69–78. Ezulike, T.O., Udealor, A., Anebunwa, F.O. and Unamma, R.P.A. (1993). Pert damage and productivity of different varieties of yam, cassava and maize in intercrop. Agricultural Science and Technology, 3(1): 99 – 102. FAO (2007). Food and Agriculture Organisation, Statistics Division, FAO., Rome. http://Faostat.org. FAO (2012). Food and Agriculture Organisation, Statistical database, FAO., Rome. http://Faostat.org Fauquet, C. and Fargette, D. (1990). African Cassava Mosaic Virus: Etiology, Epidemiology, and Control. Plant Disease 74 (6): 404 –411. Fininsa, C. (1997). Multiple cropping potentials of beans/maize. Horticultural Science, 113: 12 - 17. Githunguri, C.M., Kanayake, I.J. and Waithaka, K. (2004). Effect of the growth environment and bulking rate on cyanogenic potential of cassava tuberous roots. Agricultural Research Institute, Nairobi (Kenya). Proceedings of the 8th KARI biennial Scientific Conference, held on 11th – 15th November, pp. 151-157. Hahn, S.K., Terry, E.R., Leushner, K., Akobundu, I.O., Okali, C. and Lal, R. (1979). Cassava improvement in Africa. Field Crops Research, 23:193 - 226. Hahn, S.K. and Keyser, J. (1985) Cassava. A basic food of Africa. Out look on Agriculture 14(2): 95 - 100. Howeler, R.H. (1981). Mineral Nutrition and Fertilization of Cassava (Manihot esculenta Crantz).Centro Internacional Agricultura Tropical (CIAT). Hauggaard-Nielsen, H., Ambus, P. and Jensen, E.S. (2001). Interspecific competition, N use and interference with weeds in pea-barley intercropping. Field Crops Research, 70:101 109. Hulugalle, N.R. and Ezumah, H.C. (1991). Effects of cassava-based cropping systems on physico-chemical properties and earthed or in casts in a tropical Alfisol. Agricultural Ecosystems and Environment, 35:55 - 63. IITA (International Institute of Tropical Agriculture). (1985). Cassava in Tropical Africa. A Reference Manual. pp. 12-13, 24-25.



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Ikpi, A.E., Gebremeskel, T., Hahn, N.D, Ezumah, H.C. and Ekpere, J.A. (1986). Cassava: a crop for household food security. IITA-UNICEF Collaborative Program Report, IITA, Ibadan, Nigeria, pp. 110-113. Imo, V.O. (1995). Comparative evaluation of the effects of day-length and GA on early early growth and development of two cassava cultivars. Journal of Institute of Tropical Agriculture, Kyushu University, Japan, 18:1 – 7. Imo, V.O. (2006). Cassava Production. Barloz publishers Inc., Owerri, Nigeria. 102 p. Kawano, K. (2003). Thirty years of cassava breeding for productivity: biological and social factors for success. Crop Science, 43: 1325 - 1335. Khan, M.B. and Khaliq, A. (2004). Study of mungbean intercropping in cotton planted with different techniques. Journal of Research, Pakistan, 15 (1) 23 - 31. Lain S.L. (1985). Selection for yield potential. In: Cork, J. H. and Reyes, J. A (Eds.). Cassava: Research, Production and Utilization. Cali, Columbia: UNDP/CIAT. Liebman, M. and Dyck, E. (1993). Crop rotation and intercropping strategies for weed management. Ecological Applications, 3 (1): 92 – 122. Lozano, J.C., Toro, J.C., Castro, A. and Bellotti, A.C. (1977). Production of cassava planting material. Cassava Information center, Centro Internacional de Agricultura Tropical (CIAT). Series GE-17, 29 pp. Maini, S.B., Indira, P. and Mandal, R.G. (1977). Studies on maturity index in cassava. Journal of Root Crops, 3(2):33 - 35. Makumbi-kidza, N., Speijer, N. and Sikora, R. A. (2000). Effects of Meloidogyne incognita on growth and storage-root formation of cassava (Manihot esculenta). Journal of Nematology, 32 (4S):475 – 477. Mbah, E.U., Muoneke, C.O. and Okpara, D.A. (2003). Evaluation of cassava/soybean intercropping system as influenced by cassava genotype. Nigerian Agricultural Journal, 33:11 – 8. Mbah, E. U. and Muoneke, C. O. (2007). Productivity of cassava/okra intercropping systema as influenced by okra planting density. African Journal of Agricultural Research, 2: 223 – 231. Mbah, E.U. and Ogidi, E.O. (2012). Effect of soybean plant populations on yield and productivity of cassava and soybean grown in a cassava based intercropping system. Tropical and Subtropical Agroecosystems, 15:241 – 248. Mead, R. and Willey, R.W. (1980). The concept of a land equivalent ratio and advantages. Experimental Agriculture, 16: 217- 226. Ngendahayo, M. and Dixon, A.G.O. (2001). Effect of varying stages of harvest on tuber yield, dry matter, starch and harvest index of cassava in two ecological zones in Nigeria. In: Akoroda, M.O. and Ngeve, J.M (eds.). Root Crops in the 21st Century. Proceedings of the 7th Triennial Symposium of the International Society for Tropical Root Crops – African Branch, held at Centre International des Conference, Cotonou, Benin, 11 – 17 October, pp. 661 - 667. Njoku, D.N., Egesi, C.N., Asante, I., Offei, S.K. and Vernon, G. (2009). Breeding for improved micronutrient cassava in Nigeria: Importance, constraints and prospects. Proceedings of the 43rd Annual Conference of the Agricultural Society of Nigeria held on 20th – 23rd October, 2009 at the National Universities Commission Auditorium and RMRDC, Abuja, Nigeria. pp. 210 - 214.


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Njoku, D.N., Vernon, G.E., Offei, S.K., Asante, I.K., Egesi, C.N. and Danquah, Y. (2014a). Identification of pro-vitamin A cassava (Manihot esculenta Crantz) varieties for adaptation and adoption through participatory research. Journal of Crops Improvement, pp. 112 – 120. Njoku, D.N., Amadi, C.O., Njoku, J.C., and Amanze, N.J. (2014b). Strategies to overcome post-harvest physiological deterioration in cassava (Manihot esculenta) roots. A review. The Nigerian Agricultural Journal, 45 (1 &2):67 – 89. Ntawuruhunga, P., Ojulong, H. and Dixon, A.G.O. (1998). Genetic variability among cassava genotypes and its growth performance over time. In: Root Crops and Poverty alleviation. Proceedings of the 6th Symposium of the ISTRC – African Branch. IITA, Ibadan, Nigeria, pp. 242 - 248. Nuwamanya, E., Baguma, Y., Kawuki, R.S. and Rubaihayo, P.R. (2009). Quantification of starch physicochemical characteristics in a cassava segregating population. African Crop Science Journal, 16: 191 - 202. Ofori, F. and Stern, R. (1987). Relative sowing time and density of component crops in a maize/cowpea intercrop system. Experimental Agriculture, 23:41 – 52. Okonkwo, J.C. (2002). Evaluation of cassava genotypes for yield and response to biotic stress in Jos Plateau, Nigeria. Journal of Sustainable Agriculture & Environment, 4(9):29 - 35. Trenbath, B.R. (1993). Intercropping for the management of pests and diseases. Field Crops Res. 34:381 – 405. Okpara, D.A., Mbah, E.U. and Ojikpong, T.O. (2014). Association and path coefficients analysis of fresh root yield of high and low cyanide cassava (Manihot esculenta Crantz) genotypes in the humid tropics. Journal of Crop Science and Biotechnology, 17 (2): 1 ~ 7. Sayre, R., Beeching, J. R., Cahoon, E. B., Egesi, C., Fauquet, C., Fellman, J., Fregene, M., Gruissem, W., Mallowa, S., Manary, M., Maziya-Dixon, B., Mbanaso, A., Schachtman, D. P., Siritunga, D., Taylor, N., Vanderschuren, H. and Zhang, P. (2011). The BioCassava Plus program: biofortification of cassava for sub-Saharan Africa. Annual Review of Plant Biology 62: 251–272. Sieverding, E. and Leihner, D.E. (1984). Influence of crop rotation and intercropping of cassava with legumes on VA mycorrhizal symbiosis of cassava. Plant Soil, 80:143 – 146. Sis, I. (2013). How Non-GM cassava can help feed the world. Food plants-perennial, food shortages, GMOs, global warming/climate change. The Permaculture Research Institute, Australia 2013 International Project, Bulletin (1):1 - 2. Uguru, M.I. (2011). Crop Production, Tools, Techniques and Practice. Fulladu Publishing Company, Nsukka, Nigeria. Pp. 48 – 54. Willey, R. (1979). Intercropping–its importance and research needs. Part 1. Competition and yield advantage, Field Crops, Abstracts, 32:1 – 10. White, W.L.B., Arias-Garzon, D.I., McMahon, J.M. and Sayre, R.T. (1998). Cyanogenesis in Cassava, The Role of Hydroxynitrile Lyase in Root Cyanide Production. Plant Physiology, 116 (4):1219 – 1225.




Chapter 3

CASSAVA PRODUCTION AND UTILIZATION IN THE COASTAL, EASTERN AND WESTERN REGIONS OF KENYA C. M. Githunguri1,*, M. Gatheru2 and S. M. Ragwa2 1

Kenya Agricultural and Livestock Research Organization (KALRO) Food Crops Research Centre Kabete, Nairobi, Kenya 2 KALRO Katumani, Machakos, Kenya

ABSTRACT Cassava is the second most important food root crop in Kenya. Despite its high production in the coastal and western regions, utilization is limited to human consumption. A situational analysis on cassava production was carried out to determine its current status in the western, coastal and eastern regions of Kenya. A sample of farmers was randomly selected from each region and interviewed using a structured questionnaire. Off-farm activities were undertaken by 37% in eastern and western and 32% in the coastal regions. Access to extension services was 50% in the coast, 65% in eastern and 88% in western regions. Relative to other food crops, 66.7% of respondents ranked cassava 2nd at the coastal region while 37.5% and 57% of respondents in eastern and western regions ranked it 5th and 1st, respectively. At the coastal, western and eastern regions, 92%, 67% and 65% of the respondents intercrop cassava with other crops, while 8%, 33% and 35% grow it as a sole crop, respectively. On adoption of improved cassava varieties, western region was leading with 77% followed by coast (30%) and eastern (13%). At the coast, 23% considered lack of market as the major constraint followed by pests and diseases (16%) and destruction by large mammalian pests (11%). In eastern, 15% reported drought as the major constraint followed by lack of market (13%) and pests and disease (42%). In western, the major constraints were large mammalian pests (12%), weeds (12%), lack of planting materials (8%) and insect pests (3%). At the coastal, eastern and western regions cassava was ranked second, fifth and first respectively relative to other food crops. The western region had more improved cassava varieties than the other regions. In the coastal region, the major constraint to production was lack *

Email: [email protected].


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C. M. Githunguri, M. Gatheru and S. M. Ragwa of market while in the eastern region, the major constraint was drought and in western, the major constraints were wild animals and weeds. Cassava was utilized more as family food in western than in coastal and eastern regions. On processing of cassava and cassava based products, western region was leading followed by coastal and eastern region last. The western region was leading in the processing of dried cassava chips and composite flour. The coastal region was leading in the processing of fried cassava chips, crisps and pure flour. The eastern region was ranked least in processing with a few respondents making fried cassava chips and pure cassava flour.

INTRODUCTION Cassava (Manihot esculenta Crantz) produces about 10 times more carbohydrates than most cereals per unit area, and are ideal for production in marginal and drought prone areas, which comprise over 80% of Kenya’s land mass (Githunguri et al., 1998; Githunguri, 2002; Nweke et al., 2002). A cassava plant possesses several growth parameters and physiological processes which can be used to measure its ability to produce adequate yield under various abiotic and biotic stresses (Ekanayake et al., 1997a; Ekanayake et al., 1997b; Ekanayake, 1998; IITA, 1982, 1990a; Osiru et al., 1995). According to these authors, some of these parameters include long fibrous roots, shedding of leaves, leaf area index, leaf water potential, moderate stomatal conductance, transpiration rate, water use efficiency, crop growth rate and dry matter accumulation in the tuberous roots. Cassava can reach its production potential only where the attributes of the environment best match the crop requirements. Breeding and selection of varieties according to prevailing environmental characteristics can ensure optimal performance (IITA, 1990b). The cassava commodity system has four main components: production, processing, marketing and consumption. Linking them is the key to successful cassava products development. Strong ties with both public and private institutions engaged in research, extension and social development are essential in the accomplishment of this linkage. The exact character of these linkages will vary according to the stage of the project in technology generation and transfer (Githunguri et al., 2006). Plant breeders can contribute to better productivity and quality, agronomists to improvements in cultural practices and cropping systems, and agro-ecologists to the proper analysis of resource management issues. In order to enhance the commercial achievement of Economic Recovery Strategy goals, the Government of Kenya in collaboration with development partners established funding for enhancing agricultural commodity projects (Ministry of Agriculture (MoA), 2005). In this regard, the cassava value chain project was such a project supported to enhance cassava production, processing and marketing in Kenya and beyond our borders, especially the Common Market for Eastern and Southern Africa (COMESA) region and Europe (Kadere, 2002; Mbwika, 2002). In Eastern Kenya cassava is eaten either raw or boiled (Githunguri, 1995). Despite its great potential as a food security and income-generating crop among rural poor in marginal lands, its utilization remains low. The potential to increase its utilization is enormous with increased recipe range (Githunguri, 1995) and provision of adequate clean planting material. One of the major constraints to cassava production in the arid and semi-arid areas includes lack of adequate disease and pest free planting materials (Obukosia et al., 1993) exacerbated by the slow multiplication rates of 1:10. The Kenya Agricultural and Livestock Research Organization (KALRO) has bred cultivars tolerant to cassava mosaic


Cassava Production and Utilization in the Coastal …

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disease and acceptable to end-users (Githunguri et al, 2003). Other constraints to cassava production in Kenya including semiarid eastern include lack of adequate disease and pest free planting materials, poor cultural practices, lack of appropriate storage and processing technologies, poor market infrastructure (Githunguri and Migwa, 2003; Lusweti et al., 1997). KALRO has developed cassava varieties that are widely adapted to diverse agro-ecological zones, high yielding, early bulking, drought resistant/tolerant, resistant to major biotic and abiotic stresses and have good root quality (Githunguri et al., 2003; Githunguri, 2004). KALRO has recognized the importance of involving farmers in their selection and breeding research programmes as suggested by Bellon (2001) and Fliert and Braun (1999). Cassava is a major factor in food security across sub-Saharan Africa. In Kenya cassava is grown in over 90,000 ha with an annual production of about 540,000 tons. It is estimated that Africa produces about 42% of the total tropical world production of the crop (FAO, 1990). Cassava can grow in marginal lands, requires low inputs, and is tolerant to pests and drought (Githunguri et al., 1998; Nweke et al., 2002). Despite its great potential as a food security and income generation crop among rural poor in marginal lands, its utilization remains low in Kenya. In addition, it can be safely left in the ground for a period of 7 to 24 months after planting and then harvested as needed. Cassava is the second most important food root crop after Irish potato in Kenya. However due to its narrow production base it is ranked number 36 out of 50 in KARI’s 1991 priority setting exercise (KARI, 1995). Available statistics on cassava production in the country show a slow but steady increase in production. Cassava production in the country is concentrated in three main regions; Coastal, Central and Western region. Western and Coastal regions are the main cassava producing areas, producing over 80% of the recorded cassava output in the country (MoA, 1999). The importance of cassava as a food and cash crop in the central Kenya is however increasing. Cassava tubers are used as human food as well as animal feed. The leaves are also popular vegetable among the locals. The roots are either boiled or fried before consumption. The western (Western and Nyanza Provinces), coastal (Coast Province) and eastern (Central and Eastern Provinces) regions of Kenya account for 60%, 30% and 10% of production, respectively. Figure 1 shows a mature cassava crop grown by small holder poor households for subsistence. Despite being an important food security crop, cassava utilization in Kenya is limited to roasting and boiling of fresh roots for consumption in most growing areas. However, in Nyanza and Western provinces of Kenya, roots are also peeled, chopped into small pieces (cassava chips), dried and milled into flour for ugali. This is normally in combination with a cereal (maize or sorghum). In the Coast province cassava leaves are used as vegetable while in Eastern Province (Machakos and Kitui), raw cassava roots are chewed as a snack. Though cassava is considered to be a food security crop in the sub-Saharan Africa, its production in Kenya is low compared to other crops like maize, beans and sorghum. Its consumption is low especially in the central region of Kenya where it is considered a poor man’s crop and is usually consumed during periods of food scarcity. Despite its high production in the coastal and western regions of Kenya, utilization is limited to human consumption. In order to promote production which has been decreasing in recent years, there is need to explore and identify other uses of cassava. To achieve this, a situational analysis on cassava production, marketing, utilization and processing was carried out in three representative regions to determine the current status of the cassava value chain in Kenya.


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C. M. Githunguri, M. Gatheru and S. M. Ragwa

Figure 1. A mature Cassava Field ready for harvesting.

STUDY METHODOLOGY The study was conducted in the western (Western and Nyanza Provinces), coastal (Coast Province) and eastern (Central and Eastern Provinces) regions of Kenya. A sample of 100 farmers was randomly selected from each province and interviewed using a structured questionnaire. Figure 2 shows a farmer being interviewed. The selection of survey sites was determined by intensity of cassava production and information acquired from the County Agricultural Officers within the respective regions. Data collected included information on farmers’ socioeconomic circumstances, agronomic practices, cassava varieties, marketing, utilization and processing at household level. The data collected were analysed using the Statistical Package for Social Sciences (SPSS).

Figure 2. A farmer in his farm showing one of the project officer problems they sometimes face with cassava farming.



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RESULTS AND DISCUSSION Demographic and Socioeconomic Characteristics of Sample Farmers Growing Cassava in Coast, Eastern and Western Provinces Demographic and socioeconomic characteristics of the sample cassava farmers are shown in Table 1. The mean age of head of household was 48 years at the Coast and Eastern Provinces, and 35 years in Western Province though, the differences were statistically not significant. The average household size was 10, 6 and 9 in Western, Eastern and Coast Provinces respectively. However, the difference was not statistically significant. On average, the number of shoats (sheep and goats) owned was higher in Eastern (5) than in Coast (3) and Western (2) Provinces. The number of cows owned was significantly (p=0.01) lower in the coastal region (1) than the other two regions. Average cassava growing experience was higher in Western Province (22 years) than in Coast (17 years) and Eastern (16 years) Provinces. At the coast, 61% of the respondents were males while 39% were females. In eastern 51% and 49% respondents were males and females respectively while in western, respondents comprised 75% males and 25% females. The results indicate that there were more male headed than female headed households though the difference was not statistically significant. Table 1. Demographic and socioeconomic characteristics of sample farmers growing cassava in Coast, Eastern and Western Provinces of Kenya Province Coast Eastern Mean Std. Dev. Mean

Characteristic Age of household head (years) Size of household (no.) Number of shoats owned Number of cows owned Cassava growing experience (years)

Gender of household head Male Female Education level of Household head None Primary Secondary Off-farm income Yes No Access to extension services Yes No NS

Std. Dev. 16 3 7 3 15

Western Mean Std. Dev. 35 16 9 4 2 2 3 2 22 14

χ2 98.773NS 35.217NS 31.235NS 46.646*** 62.298NS

48 6 3 1 17

13 3 4 2 14

48 6 5 3 16

Number of farmers

Percent of farmers

19 12

61 39

Number Percent Number Percent χ2 of of of of farmers farmers farmers farmers 1.708NS 18 51 6 75 17 49 2 25 1.589NS

10 14 7

32 45 23

8 21 6

23 60 17

2 4 2

25 50 25

10 21

32 68

13 22

37 63

3 5

37 63

15 15

50 50

22 12

65 35

7 1

88 12

0.194NS

=Non-significant; ***=Significant at p=0.01.


4.807NS

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Literacy level was lowest at the coastal region where 32% had no formal education, 45% had primary and 23% had secondary education. In the eastern region, 17%, 60%, and 23% had secondary education, primary education and no formal education respectively. In western region, 25%, 50%, and 25% had secondary, primary, and no formal education respectively. Off-farm activities were undertaken by 32% in the coastal region, 37% in eastern and western regions. Access to extension services was 50% in the coast, 65% in eastern and 88% in western regions even though the differences were not significant.

Cassava Production Production and consumption of cassava at the Coast, Eastern, and Western Provinces of Kenya was recorded in 1950, 1957 and 1960, respectively. Cassava growing and consumption may have an earlier history of introduction into these regions, but the survey could only capture when the farmer started growing cassava. This does not rule out an earlier introduction and history of cassava in Kenya. From the survey, a cumulative curve showed that there was a slow increase in cassava cultivation in the periods between 1950 and 1997, after which rapid cassava cultivation was recoded up to 2006 (Figure 3). This could be attributed to food security campaigns, which were initiated by then and conservation of indigenous food crops. Each region showed a different trend in cassava cultivation increments, interest and production. At the coastal region, cassava production started in 1950, picked up slowly until 1993, and then there was a rapid adoption rate up to 2006 (Figure 4). A similar trend was observed in eastern region but in western, there was a steady increase in adoption rate of cassava cultivation since its introduction (Figures 5 and 6). The importance of cassava relative to other food crops across the three regions was assessed. Relative to other food crops, 66.7% of respondents ranked cassava 2nd at the coastal region while 37.5% and 57% of respondents in eastern and western regions ranked it 5th and 1st respectively.

Cropping Systems and Cassava Varieties At the coastal, western and eastern regions, 92%, 67% and 65% of the respondents intercrop cassava with other crops as is depicted in Figure 7, while 8%, 33% and 35% grow it as a sole crop respectively. The commonly used cassava varieties at the coast were Kibandameno (55%) and Kaleso (34%). In Eastern region, 78% of the varieties grown were unknown though there were a few farmers (6.3%) growing an improved variety locally known as Mucericeri. In western Kenya, many of cassava varieties were recorded with Migyera (23%) and SS4 (23%) being more preferred in the region. Other varieties available in the region were Magana (12%), Mucericeri (8%) and Adhiambo Lera (8%). The presence of more varieties in the western region is attributed to the cross border trade with Uganda. On adoption of improved cassava varieties, western region was leading with 77% followed by coast with 30% and eastern with 13%. At the coast, the main source of planting material was from own fields (44%) and other farmers (29%). In the eastern region, the main source of planting material was from other



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farmers (53%) and from own fields (23%) while in the western region, the main source was from the Ministry of Agriculture (77%). At the coast 91% of the respondents, plant cassava during the April rains while 72% in eastern, plant cassava during the October rains. In the western region, cassava is planted in both seasons.

Figure 7. Cassava intercropped with other cereals. This is a common practice with farmers in all the cassava growing zones.

70

60

Number of farmers

50

40

30

20

10

0

2006 2005 2003 2002 2001 2000 1997 1996 1995 1994 1993 1990 1989 1988 1987 1985 1983 1982 1980 1977 1975 1969 1968 1966 1964 1960 1957 1950 Year

Figure 3. Overall trend in cassava growing in Coast, Eastern and Western Provinces of Kenya for a period of 56 years.


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30

25

Number of farmers

20

15

10

5

0

1950 1957 1968 1975 1980 1983 1987 1988 1989 1993 1997 2001 2002 2003 2005 Year

Figure 4. Overall trend in cassava growing in Coast Province of Kenya for a period of 55 years.

Number of farmers

30

20

10

0

2006

2005

2003

2002

2001

2000

1997

1996

1995

1994

1990

1988

1985

1983

1982

1977

1966

1964

1957

Year

Figure 5. Overall trend in cassava growing in Eastern Province of Kenya for a period of 51 years. 8

7

Number of farmers

6

5

4

3

2

1 1960

1969

1980

1988 1990 Year

1994

1995

2001

Figure 6. Overall trend in cassava growing in Western Province of Kenya for a period of 41 years.



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Main Reasons for Growing Specific Cassava Varieties In the coastal region, farmers preferred high yielding varieties. Other preferred parameters were maturity period, taste (sweet taste), pests and disease resistance. In the eastern region farmers consider marketability (42%) as the most important parameter followed by taste 17%. High yielding varieties were also preferred. In western, 55% of respondents considered marketability as the most important parameter followed by resistance to pests and diseases and, earliness in maturity.

Major Constraints to Cassava Production At the coast, 23% of the respondents considered lack of market as the major constraint followed by pests and diseases (16%) and destruction by large mammalian pests (11%). In eastern, 15% of the respondents reported drought as the major constraint followed by lack of market (13%) and pests and disease (42%). In western, the major constraints were large mammalian pests (12%), weeds (12%), lack of planting materials (8%) and insect pests (3%).

Pests and Disease Control Measures Only 10% of respondents used mechanical methods to control termites at the coast. Except for eastern region where 7% of respondents used chemicals to control termites, there were no chemical control methods in the other regions. In the western region, 50% and 25% of respondents use biological control for cassava green mite and whiteflies respectively. For control of diseases, 18% of respondents at the coast used mechanical methods to control cassava mosaic virus while in eastern and western regions, there were no control measures taken.

Cassava Utilization One hundred percent, 22% and 13% of respondents at the coast, eastern and western regions, respectively, use cassava leaves as vegetable. Besides being used as vegetable, 100% of respondents in western and 67% in eastern use cassava leaves as livestock feed. At the coast, 36% of respondents use cassava stems as firewood and 32% sell stems as planting materials to other farmers. In eastern, 33% of respondents use cassava stems as firewood while 30% use stems as planting materials. In western, 50% of respondents sell cassava stems as planting materials while 50% use it as firewood. Figure 7 shows a popular method of preserving clean planting materials by farmers in the coastal region. It was noted that 100% of respondents at the coast use cassava roots as family food, for sale and as gifts while 19% uses it purely as family food. In eastern, 100% of respondents use cassava as family food and for sale in local markets while 19% give cassava as gifts. In western Kenya, 100% of respondents use cassava as family food and for sale in local markets.


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Figure 7. This is one method of preserving clean planting materials by farmers mostly in the coast region.

Sale of Cassava Roots At the coast, 46%, 32% and 21% of respondents making decision on the sale of cassava were men, women and both sexes respectively. In eastern, 67% of respondents reported that decision on sale of cassava is made by women, 24% by men and 10% by both. In western, 25% of respondents reported that decision on sale of cassava was made by men, 25% by women and 50% by both. After the decision on sale had been made, 71% of respondents at the coast reported that actual sales were done by women, 4% by men and 25% by both. In eastern, 86% of cassava sale was by women, 10% by men and 4% by both sexes. In western Kenya 100% of respondents reported that cassava sale is done by women. Figure 8 shows a cassava trader narrating his mixed fortunes and misfortunes in the cassava business. At the coast 12% of respondents sold their cassava at the farm gate, 65% at the local markets, 15% to other places (e.g., Tapioca in Mazeras) and 8% at both farm gate and local markets. In eastern Kenya, 29% of respondents sold their cassava at farm gate, 65% at the local markets, 6% to different destinations while in western Kenya 25% sold their cassava at farm gate and 75% at the local markets. Ninety three percent (93%) of farmers at the coast sold their produce on cash basis and 7% on credit (mainly to big processors/factories). In eastern, 85% sold their cassava on cash basis, 5% on credit and in kind. In western Kenya, 100% of respondents reported that sales were on cash basis. At the coast, the main dealers in cassava sales were wholesalers (21%), retailers (25%) and both wholesalers and retailers (25%). In eastern, the main buyers were local consumers (53%) while 32% were both retailers and consumers. In western Kenya, 63% of both retailers and local consumers were the main buyers of cassava followed by both wholesalers and consumers at 13%.



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Figure 8. Cassava trader narrates fortunes and misfortunes in cassava business. There is no exact weight measure for a 90-kg sack during peak season hence sales are at random.

Cassava Processing Major cassava products processed at the coast were fried cassava chips (cassava French fries) (21%) and cassava flour (11%). Other processed products included cassava crisps, halfcakes and composite flour (a mixture of cassava and other cereals). In eastern province, 3% of processors make cassava chips and 10% cassava flour. In western region 38%, of processors make cassava chips (dried chopped and sun dried cassava) and 38% composite flour (cassava mixed with other cereals). Other products include crisps, chapati and starch at 13%.

Quality Characteristics Mostly Preferred for Cassava Products At the coast, 19% of respondents preferred white colour as the most important characteristics. Fiber-free cassava varieties and good taste were preferred by 8% of the respondents while size and colour were preferred by 8% of others. In eastern region, white colour and texture were preferred by 38% and taste by 13% of the respondents respectively. In western, moisture content (properly dried cassava chips) was preferred by 17% white colour by 67% of the respondents. At the coast region, 31% and 26% of respondents preferred Kibandameno and Kaleso varieties respectively for processing cassava into various products. In eastern, 67% of respondents preferred all varieties for processing while in western, 51% preferred Migyera followed by SS4 and Magana at 17% each.


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Farmers’ Knowledge of Other Products Processed In western, 78% of respondents were aware of other cassava products made elsewhere through their local markets while 18% had learnt about them through seminars organized by the Ministry of Agriculture and Farmer Field Schools. In eastern, 29% of respondents had learnt about the products from KARI and 24% through NGOs and community-based organizations. In the coastal region, 44% of respondents had learnt about other products from supermarkets at Mombasa.

Constraints in Processing In the coastal region, 33% of farmers lacked appropriate equipment to process various cassava products. Other reasons for not processing cassava included lack of capital (22%) and knowledge (22%). In eastern, 56% of the respondents reported the major reason for not processing as lack of knowledge, while 18% attributed it to non-availability of cassava for processing. Other reasons included lack of appropriate equipment (6%). In western Kenya, 29% of respondents faced challenges of new technology adoption in processing. Other reasons identified included lack of knowledge and expensive processing oil.

CONCLUSION The study showed that the importance of cassava relative to other food crops differed across the three regions. At the coastal, eastern and western regions it was ranked second, fifth and first respectively. In the western region, there were more improved cassava varieties than in the other regions. This can be attributed to access to extension services and exchange of varieties across the Ugandan border. In the coastal region, the major constraint to production was lack of market while in the eastern region, the major constraint was drought and in western, the major constraints were wild animals and weeds. There was more utilization of cassava as family food in western than in coastal and eastern regions. In all the regions, the sale of cassava roots and cassava-based products was carried out by women and on cash basis. On processing of cassava and cassava based products, western region was leading followed by coastal and eastern region last. The western region was leading in the processing of dried cassava chips and composite flour. The coastal region was leading in the processing of fried cassava chips, crisps and pure flour. The eastern region was the last in processing with a few respondents making fried cassava chips and pure cassava flour. The quality characteristics that were preferred for cassava and cassava-based products were mainly white colour, fibre-free cassava roots and sweet taste. There was more awareness on processed products in western where most respondents had heard about products processed elsewhere and a few had learnt through seminars organized by the Ministry of Agriculture. At the coast, the main constraint in processing was lack of appropriate equipment and capital. In eastern, the main constraint in processing was lack of knowledge and enough cassava. In western, the main constraint was lack of modern processing equipment.



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REFERENCES Bellon, M.R. 2001. Participatory Research Methods for Technology Evaluation. A Manual for working with Farmers. Mexico, D.F.: CIMMYT, 93p. Ekanayake, I.J., D.S.O. Osiru and M.C.M. Porto. 1997a. Morphology of cassava. IITA Research Guide 61: 1 - 30. Ekanayake, I.J., D.S.O. Osiru and M.C.M. Porto. 1997b. Agronomy of cassava. IITA Research Guide 60: 1 - 30. Ekanayake, I.J. 1998. Screening for abiotic stress resistance in root and tuber crops. IITA Research Guide 68: 46pp. FAO, 1990: Roots, Tubers, Plantains and Bananas in human nutrition. FAO, Rome, Italy. Goering, T.J. 1979. Tropical root crops and rural development. World Bank Staff working Paper No. 324. Washington, D.C., World Bank. Fliert, E. van de and A.R. Braun. 1999. Farmer Field School for Integrated Crop Management of Sweetpotato. Field Guides and Technical Manual. Andi Offset, Yogyakarta, Indonesia: CIP,III-101p. Githunguri, C.M. 1995. Cassava food processing and utilization in Kenya. In: Cassava food processing. T. A. Egbe, A. Brauman, D. Griffon and S. Treche (Eds.) CTA, ORSTOM, pp119-132. Githunguri, C. M., I. J. Ekanayake, J. A. Chweya, A. G. O. Dixon and J. Imungi. 1998a: The effect of different agro-ecological zones on the cyanogenic potential of six selected cassava clones. Post-harvest technology and commodity marketing, IITA, 71-76pp. Githunguri, C.M., I.J. Ekanayake, J.A. Chweya, A. G. O. Dixon and J.K. Imungi. 1998b. The effect of different agroecological zones and plant age on the cyanogenic potential of six selected cassava clones. In: (R.S.B. Ferris Ed.) Post-harvest technology and commodity marketing. Proceedings of a postharvest conference held on 2 November – 1 December 1995, Accra, Ghana. IITA, Ibadan, Nigeria, 71 - 76pp. Githunguri, C.M. 2002. The influence of agro-ecological zones on growth, yield and accumulation of cyanogenic compounds in cassava. A thesis submitted in full fulfilment for the requirements for the degree of Doctor of Philosophy in Crop Physiology, Faculty of Agriculture, University of Nairobi, 195pp. Githunguri, C.M., Y.N. Migwa, S.M. Ragwa and M.M. Karoki. 2003. Cassava and sweetpotato agronomy, physiology, breeding, plant protection and product development. Root and Tuber Crops Programme in KARI-Katumani. Paper presented at the Joint Planning meeting organized under the Eastern Province Horticulture and Traditional Food Crops Project, held at Machakos, Kenya on 5th 7th March 2003, 5p. Githunguri, C.M. and Y.N. Migwa. 2003. Sweetpotato Feathery Mottle Virus Resistance and Yield Characteristics of Different Sweetpotato Cultivars in Machakos and Makueni Districts of Kenya. In: Githunguri C.M., Kwena, K., Kavoi, J., Okwach, E.W., Gatheru, M. and Abok, J.O. (Eds.). Kenya Agricultural Research Institute, KARI Katumani Research Centre annual report 2002. Pp. 91 - 95. Githunguri, C.M. 2004. Farmers’ Participatory Perspectives on Sweetpotato Cultivars in Kathiani Division of Machakos District, Kenya. In: Book of Abstracts of the 9th Triennial Symposium of the International Society for Tropical Root Crops- Africa Branch (ISTRC-AB), Mombasa, Kenya, 31st October – 5th November 2004. 84pp.


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Githunguri, C. M, E. G. Karuri, J. M. Kinama, O. S. Omolo, J. N. Mburu, P. W. Ngunjiri, S. M. Ragwa, S. K. Kimani and D. M. Mkabili. 2006. Sustainable Productivity of the Cassava Value Chain: An Emphasis on Challenges and Opportunities in Processing and Marketing Cassava in Kenya and Beyond. KAPP Competitive Agricultural Research Grant Fund, pp. 106. IITA. 1982. Management practices for production of cassava planting materials. IITA tuber and Root crops production Manual series, 244pp. IITA. 1990a. Cassava in Tropical Africa. Reference Manual IITA, 176pp. IITA. 1990b. Targeting cassava Breeding and Selection. In: Proceedings of the fourth West and Central Africa Root Crops workshop, held in Lome, Togo, 12-16 December 1988. IITA Meeting Reports Series 1988/6, pp. 27-30. Kadere, T.T. 2002. Marketing opportunities and quality requirements for cassava starch in Kenya. In Proceedings of regional Workshop on improving the cassava sub-sector, held in Nairobi, Kenya, April 2002, 8-18, pp. 81 - 86. KARI, 1995: Cassava Research Priorities at the Kenya Agricultural Research Institute, Cassava Priority Setting Working Group. Lusweti, C.M., W. Kiiya, C. Kute, A. Laboso, C. Nkonge, E. Wanjekeche, T. Lobeta, S. Layat, A. Kakuko, and E. Chelang. 1997. The farming systems of Sebit: In: Summary from PRA activities. Pp. 54 - 67. Mbwika, J.M 2002. Cassava sub-sector analysis in the Eastern and Central African region. In Proceedings of regional Workshop on improving the cassava sub-sector, held in Nairobi, Kenya, April 2002, 8-18, pp. 8-18. Ministry of Agriculture, 1999: Provincial Annual Reports. Ministry of Agriculture (MoA). 2005. Strategy for Revitalizing Agriculture 2004 – 2014. Ministry of Agriculture, 23pp. Nweke, F. I., D. S. C. Spencer and J. K. Lynam. 2002: Cassava transformation. International Institute of Tropical Agriculture. 273p. Obukosia, S.D., Muriithi, and R.S. Musangi. 1993. Biotechnological approach to the improvement of root, tuber and horticultural crops in Kenya. Production constraints and potential solutions. Proceedings of the national agricultural biotechnology workshop, Nairobi, PP. 92-106. Osiru, D.S.O., M.C.M. Porto, and I.J. Ekanayake. 1995. Physiology of cassava. IITA, Research Guide 55: 3 - 19.




Chapter 4

SOCIO-ECONOMIC DETERMINANTS OF MODERN TECHNOLOGY ADOPTION AND THE INFLUENCE OF FARM SIZE ON PRODUCTIVITY AND PROFITABILITY IN CASSAVA PRODUCTION: A CASE STUDY FROM SOUTH-EASTERN NIGERIA* Chidiebere Daniel Chima† and Sanzidur Rahman‡ School of Geography, Earth and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth, UK

ABSTRACT The chapter investigates the influence of socio-economic factors on the adoption of individual components of modern agricultural technology (i.e., HYV seeds and inorganic fertilizers) in cassava and also examines farm size–productivity and farm size– profitability relationships of cassava production in South-eastern Nigeria including a discussion of constraints in the cassava sector. The hypotheses of the study are that farmers selectively adopt components of modern agricultural technology depending on their socio-economic circumstances and inverse farm size–technology adoption, size– productivity and size–profitability relationships exist in cassava production. The research is based on an in-depth farm-survey of 344 farmers from two states (243 from Ebonyi and 101 from Anambra states) of South-eastern Nigeria. The results show that the sample respondents are dominated by small scale farmers (78.8% of total) owning land less than 1 ha. The average farm size is small estimated at 0.58 ha. The study clearly demonstrated that inverse farm size–technology adoption and farm size–productivity relationships exist in cassava production in this region of Nigeria but not inverse farm size–profitability The chapter was developed from the first author’s PhD thesis submitted at the School of Geography, Earth and Environmental Sciences, University of Plymouth, UK in 2015. The data required for this project was generously funded by the Seale-Hayne Educational Trust, UK. All caveats remain with the authors. † Address for correspondence: Dr. Chidiebere Daniel Chima, School of Geography, Earth and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth, PL4 8AA, Phone: +44-7883005944; +44-1752585911, Fax: +44-1752-584710, E-mail: [email protected]. ‡ Phone: +44-1752-585911, Fax: +44-1752-584710, E-mail: [email protected]. *


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Chidiebere Daniel Chima and Sanzidur Rahman relationship. The level of modern technology adoption is low and mixed and farmers selectively adopt components of technologies as expected and use far less than recommended dose of fertilizers. Only 20.35% of farmers adopted both HYV cassava stem and fertilizers as a package. The bivariate probit model diagnostic reveals that the decision to adopt modern technologies are significantly correlated, implying that univariate analysis of such decisions are biased, thereby, justifying use of the bivariate approach. The most dominant determinant of modern technology adoption in cassava is farming experience and remoteness of extension services depresses adoption. A host of constraints are affecting Nigerian agricultural sector, which includes lack of extension agents, credit facilities, farm inputs, irrigation, value addition and corruption, lack of support for ADP staff and ineffective government policies. Policy implications include investment in extension services, provision of credit facilities and other infrastructures (e.g., irrigation, ADP staff), training of small farmers in business skills, promotion of modern technology as a package as well as special projects (e.g., Cassava Plus project) in order to boost production of cassava at the farm-level in Nigeria.

Keywords: modern technology adoption, farm size categories, profitability, bivariate probit model, cassava production, Nigeria

1. INTRODUCTION Agriculture has been the mainstay of the economy of Nigeria and many other African countries, providing employment, food and source of livelihood for their rural and increasing population (Nwa, 2003). In Nigeria, the agricultural sector is the major employer, with nearly 70% of the country’s labour force engaged in one form of agriculture or the other (Abolagba et al., 2010). The sector is still characterised by small scale farmers using traditional farming methods with very low level of mechanization and modern technologies leading to low level of productivity (Chima, 2015). In sub-Saharan Africa, cassava is very important not just as a food crop but as a major source of cash income for a large population (NISER 2013). It is grown in over 90 countries and is the third most important source of calories in the tropics, after rice and maize (Tsegia et al, 2002). It is a staple for half a billion people in Africa, Asia and Latin America. Cassava is grown mainly by poor farmers, many of them women and often grown in marginal lands. For these people and their families, cassava is vital for food availability and income generation and it is a major source of commercial feed, fibre for paper and textile manufacturers and starch for food and pharmaceutical industries (Tsegia et al, 2002 and CGIAR, 2011). According to Westby (2008), world cassava demand is projected to reach 275 million tonnes by 2020 while Africa now produces about 62% of the total world production with Nigeria being the largest producer with 54 million tonnes of output in 2013 (FAOSTAT, 2015). Despite this, less than 5% of the output produced in Nigeria is used for industries while 95% is used for human consumption (NISER, 2013). In spite of the position of Nigeria as the leading producer of cassava in the world, the country still imports significant quantities of cassava products and by-products, such as starch, flour and sweeteners (Olukunle, 2016). This constituted a drain on the foreign exchange resources of the country given the recent collapse of world crude oil market. What is more worrisome is that a good proportion of these raw materials can be sourced from agricultural produce locally. For instance, in 2008 and 2011, raw material imports into Nigeria averaged $8.3 billion (18.9%) and $8.2 billion


Socio-Economic Determinants of Modern Technology Adoption …

57

(12.5%) respectively. As a proportion of total raw materials imported into the country, industrial agricultural raw materials accounted for 26.6% ($2.2 billion) in 2008 and rose sharply to 69.8% (£5.7 billion) in 2011 (Sanusi 2012). This trend is unsustainable given the declining economic condition of the country and hence the urgent need to diversify the economy and allowing the agricultural sector to play its role as a main source of foreign exchange. The average yield level of cassava in Indonesia is 19 mt/ha which is much higher than that in Nigeria which is estimated at 14.7 mt/ha (Nang’ayo et al., 2007). In contrast Thailand is the largest exporters of cassava products, exported a little under $1 billion USD of cassava products in 2009, has an efficient cassava value-added chain (APFCTN, 2014). A comparison of the Nigeria and Thai cassava sectors reveals that the cassava sector in Nigeria is plagued by low productivity; with average yields of 11.7 ton/ha, compared to 22 ton/ha in Thailand. Also Thai cassava yields have increased @ 1.7% per year over the last 15 years while yields in Nigeria have stagnated during the same period (FAOSTAT, 2009). The low productivity of the cassava sector in Nigeria has led to high costs per unit of production. The cost of cassava root production per ton is USD 10 higher in Nigeria than in Thailand. This has made Nigerian cassava products unable to compete with imported substitutes leading to a lack of demand for cassava by industrial users who prefer to import cheaper raw materials (APFCTN, 2014). Although both are tropical countries with similar production constraints such as low level of input use, high variability in commodity price and lack of adequate infrastructure (Sugino and Mayrowani, 2009), higher productivity in Thailand is mostly due to higher incidence of fertilizer use and mechanization. While in Nigeria, there is little or no use of chemical fertilizer in cassava production and farming is done by manual labour; especially weeding operation (Chima, 2015). Given this backdrop, this chapter is aimed at investigating the influence of socioeconomic factors on the adoption of individual components of modern agricultural technology (i.e., HYV cassava stem and inorganic fertilizers) in cassava and to examine farm size–productivity and farm size–profitability relationships in cassava production at the farmlevel in South-eastern Nigeria including a discussion of constraints in the cassava sector. The hypotheses of the study are that farmers selectively adopt components of modern agricultural technology depending on their socio-economic circumstances and inverse farm size– technology adoption, size–productivity and size–profitability relationships exist in cassava production. Bivariate probit model were used to determine the socio-economic determinants of modern agricultural technology adoption in cassava production given its advantage over univariate probit of allowing the evaluation of more than one technology (HYV stem and inorganic fertilizer) at the same time (Rahman, 2003 and Chirwa, 2005). The rest of the chapter is divided into seven sections. Section 2 presents the methodology, including study area, source of data and analytical framework. Sections 3, 4 and 5 present the results of farm-size technology adoption, farm-size productivity and farm-size profitability relationships respectively. Section 6 presents the results of the determinant of modern agricultural technology adoption in cassava. Section 7 provides discussion of the constraints of cassava production and modern agricultural technology adoption in the study area. Finally, Section 8 provides conclusions and policy implications.


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Chidiebere Daniel Chima and Sanzidur Rahman

2. METHODOLOGY 2.1. Study Area and Data The primary study area is south-eastern Nigeria. Two states were chosen, Ebonyi and Anambra states. Ebonyi with 13 Local Government Area (LGA) is a rural/agrarian state was created on 1st October 1996 from Enugu and Abia states; and has a total landmass of 5,935 sq km of which 80% is rich in arable land (Nwibo, 2012). It has an estimated population of 2,173,501 with a growth rate of 3.5% per annum (NPC, 2006). The 70% of population are rural and the economy is primarily dependent on agriculture, which contributes about 90% to Gross Domestic Product (GDP). About 75% of its people are engaged in one form of farming or another and are mostly subsistence farmers (Ebonyi Agricultural Policy 2010). Anambra is more urban and was carved out of the old Anambra state in 1991 and has a land area of 4,415.54 sq km and population of 4.18 million; 70% of the land is rich and suitable for agricultural production (Nkematu, 2000 and NPC, 2006). The state has 21 Local Government Areas (LGA), consisting of 177 autonomous communities. The climate can generally be described as tropical with two identifiable seasons, rainy or wet and dry seasons. Farming is the predominant occupation of the rural people, the majority of whom are small holder subsistence farmers. Data used for the study were drawn from the two states; Ebonyi and Anambra states of Nigeria. Based on the cell structure developed by Agricultural Development Programme in Nigeria, three local government areas (LGAs) from each state were randomly selected. Then, 10 communities/villages from each of the LGA were then chosen randomly. Next farmers were chosen from these communities using a simple random sampling procedure. The total number of farm households in each village formed the sample frame. Then the sample size (n) of the household units in the study area is determined by applying the following formula (Arkin and Colton, 1963):

n

Nz 2 p(1  p) Nd 2  z 2 p(1  p)

Where n = sample size; N = total number of farm households; z = confidence level (at 95% level z = 1.96); p = estimated population proportion (0.5, this maximizes the sample size); and d = error limit of 5% (0.05). Application of the above sampling formula with the values specified in fact maximizes the sample size and yielded a total sample of 344 cassava farmers (Ebonyi State = 243; Anambra State = 101) in the study areas used for this study.

2.2. Profitability and Benefit Cost Ratio (BCR) Analytical Framework This section discusses the framework to analyse profitability and Benefit Cost Ratio. This is done by analysing Total Variable Cost (TVC); Total Fixed Cost (TFC), Total Revenue (TR), Gross Margin (GM), Net Profit and Benefit Cost Ratio (BCR) for cassava farm enterprise. The key variables that are used to determine profitability of farm enterprise in this



59

study are defined and explained in this section. Also BCR are defined and explained. The key variables are: Variable Cost (VC): This is the cost that changes with the level of production of the farmer. i.e., if the farmer increases his/her farming activities or scale up his/her farming then the variable cost is likely to increase too. In this study, the variable cost is the sum total of total material input cost, total labour cost and transportation cost (Table 5.1, Section A). The services of farm equipment and tools are not captured in the variable cost because none of the farmers have access to farm machinery or tools; all farmers still use crude farm implements like hoes and cutlasses. Also there is no specific farm house. Instead farmers store their farm products in their residential house or local barns. Unit price of output: The unit price used to determine the Total Revenue (TR) is the actual selling price for the farmers who sold their farm output. For the farmers who did not sell their farm produce, the mean selling price of those who sold theirs were imputed to determine their TR. Total Revenue (TR): This is the total output of the farm enterprise multiplied by their market unit selling price for the farmers who sold their farm produce and the mean market unit selling price for the farmers who did not sell their farm produce. The TR varies from one farm enterprise to the other. Gross Margin (GM): This is the difference between the Total Revenue (TR) of each farm enterprise and the Total Variable Cost (TVC). (Note: GM=TR-TVC). Fixed Cost (FC): These are the costs associated with farm production but are fixed, which means that they remain the same throughout the production period. For this study the fixed costs are the mean cost for farmers renting-in land for farm production and mean interest paid on any loan acquired for farm production by the farmers who have loan. It is important to note that the mean cost of renting-in land and loan interest payment are just for the farmers who rented-in land or had any loan, to avoid distort comparisons with farmers that do not use these facilities. Net Profit (NP): This is the difference between Gross Margin (GM) and the Total Fixed Cost (TFC) for each farming enterprise (Note: NP=GM-TFC) Benefit Cost Ratio (BCR): This is the Total Revenue (TR) for each farming enterprise divided by their Total Cost (TC). It is a ratio and implies the return for every Naira (Nigeria currency) invested in the farm enterprise. The BCR value is good if it is positive and has the value of 1 or more. Therefore, the higher the BCR value, the better the return on every additional naira invested on that farm enterprise (Note: BCR=TR/TC).

2.3. The Theoretical Framework: Bivariate Probit Model Many studies have analysed the determinants of adopting modern/improved agricultural technologies (including HYVs of rice, wheat and/or maize, cassava) by farmers in Nigeria and other developing countries. These studies are largely univariate probit or Tobit regressions of technology adoption on variables representing the social economic circumstances of farmers (e.g., Hossain 1989; Ahmed and Hossain 1990; Shiyani et. al 2002; Rahman 2003, Floyd et. al. 2003; Ransom et. al. 2003; Barrett 2004, Chirwa 2005). The implicit theory underpinning such modelling is the assumption of utility maximization by rational farmers which is described below.


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We denote the adoption of HYV as dv and the adoption of fertilizer as 𝑑𝑓; where 𝑝 = 1 for adoption and 𝑝 = 0 for non-adoption. The underlying utility function which ranks the preference of the 𝑖 𝑡ℎ farmer is assumed to be a function of farmer as well as farm-specific characteristics, Z (e.g., family size, farming experience, farm size, extension contact etc.) and an error term with zero mean. 𝑈𝑖1 (𝑍) = 𝛽1 𝑍𝑖 + 𝜀𝑖1 For adoption and 𝑈𝑖0 (𝑍) = 𝛽0 𝑍𝑖 + 𝜀𝑖0 For non-adoption Since the utility derived is random, the 𝑖𝑡ℎ farmer will adopt an agricultural system if and only if the utility derived from the adoption is higher than non-adoption; i.e., 𝑈𝑖1 > 𝑈𝑖0 Thus, the probability of adoption of the 𝑖𝑡ℎ farmer is given by (Nkamleu and Adesina 2000; Ajibefun, et al. 2002 and Rahman 2008): 𝑝 (𝐼) = 𝑝(𝑈𝑖1 > 𝑈𝑖0) 𝑝(𝐼) = 𝑝(𝛽1 𝑍𝑖 + 𝜀𝑖1 > 𝛽0 𝑍𝑖 + 𝜀𝑖0 ) 𝑝(𝐼) = 𝑝(𝜀𝑖0 − 𝜀𝑖1 ) < 𝛽1 𝑍𝑖 − 𝛽0 𝑍𝑖 ) 𝑝(𝐼) = 𝑝(𝜀𝑖 < 𝛽𝑍𝑖 ) 𝑝(𝐼) = ∅(𝛽𝑍𝑖 )∅ Where ∅ is the cumulative distribution function for 𝜀 the functional form of ∅ depends on the assumption made for the error term 𝜀, which is assumed to be normally distributed in a probit model. Thus for the 𝑖𝑡ℎ farmer, the probability of the adoption of a diversified HYV and fertilizer respectively is given by: 𝛽𝑍𝑖 1

∅𝑑𝑣 (𝛽𝑍𝑖 ) = ∫𝛼

√2𝜋

𝛽𝑍𝑖 1

∅𝑑𝑓 (𝛽𝑍𝑖 ) = ∫𝛼

√2𝜋

−𝑡 2

𝑒𝑥𝑝 {

2 −𝑡 2

𝑒𝑥𝑝 {

2

} 𝑑𝑡

(1)

} 𝑑𝑡

(2)

The two equations can each be estimated consistently with the single-equation probit method but such a commonly used approach is inefficient because it ignores the correlation between the error terms 𝜀𝑑𝑣 𝑎𝑛𝑑 𝜀𝑑𝑓 of the underlying stochastic utility function of HYV and fertilizer respectively. We apply the bivariate probit model in order to circumvent this limitation. Therefore, the bivariate probit model which is based on the joint distribution of the two normally distributed variables and is specified as follows: (Greene 2003 and Rahman 2008): f (dv, df ) 

1 2 dv df

1  2

e

 (   2  ) /(2(1  ) 2

2

dv

df

2

dv

df


(3)

Socio-Economic Determinants of Modern Technology Adoption … 𝜀𝑑𝑣 −

𝑑𝑣−𝜇𝑑𝑣 𝜎𝑑𝑣

𝑎𝑛𝑑 𝜀𝑑𝑓 −

61

𝑑𝑓−𝜇𝑑𝑓 𝜎𝑑𝑓

Where 𝑝 is the correlation between dv and df, the covariance is 𝜎𝑑𝑣,𝑑𝑓 = 𝜌𝜎𝑑𝑣 𝜎𝑑𝑓 ; 𝑤ℎ𝑖𝑙𝑒 𝜇𝑑𝑣 , 𝜇𝑑𝑓 , 𝜎𝑑𝑣 𝑎𝑛𝑑 𝜎𝑑𝑣 are the means and standard deviations of the marginal distributions of dv and df respectively. The distribution is independent if and only if 𝑝 = 0. The full maximum likelihood estimation procedure is utilized using the software program NLOGIT-4 (Economic software, Inc. (ESI) 2007). Therefore, the bivariate probit model is developed to empirically investigate the socioeconomic factors underlying the decision to adopt HYV seed and/or inorganic fertilizer. The dependent variable is whether the farmer adopts HYV seed and/or inorganic fertilizer; for HYV represented by dv, the variable takes the value 1 if the farmer adopts HYV and 0 if otherwise. Similarly, for inorganic fertilizer represented by 𝑑𝑓; the variable takes the value 1 if the farmer adopts fertilizer and 0 if otherwise.

3. AGRICULTURAL TECHNOLOGY ADOPTION AND FARM-SIZE RELATIONSHIPS This section discusses the results of agricultural technology adoption patterns by farm size categories of the respondents. It evaluates whether agricultural technology is being adopted as a package and/or whether the inverse farm size-technology adoption relationship exists in the study area. Taken as a whole, Table 3.1 shows that only 20.35% of the respondents adopted agricultural technology as a package (fertilizer and HYV stem) in the study area, of which most of the adopters are small scale farms (80%) and the others are medium (14.29%); large (5.71%) scale farms respectively. This finding is consistent with Madukwe, et al. (2002) and Agwu, (2004) who noted a low adoption of agricultural technology among cowpea farmers in his study of factors influencing adoption of improved cowpea production technology in Nigeria. Table 3.1. Agricultural technology adoption pattern by farm-size Farm Category Small Medium Large Total

Agricultural Technology Adoption Pattern in Percentage Non Only Fertilizer Only HYV Adopters of Adopters Adopters Adopters Both 50.55 9.23 19.56 20.66 (137) (25) (53) (56) 43.90 4.88 26.83 24.39 (18) (2) (11) (10) 62.50 9.38 15.63 12.50 (20) (3) (5) (4) 8.72 50.87 20.06 20.35 (175) (30) (69) (70)

Total Adopters of Technology 49.45 (271) 56.10 (41) 37.50 (32) (344)

Source: Field Survey 2011 (NB: the parentheses are predicted estimated frequency).

Similarly, only 8.72% and 20.06% of respondents adopted only one element of the technology package, which are inorganic fertilizer technology and HYV stem technology


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respectively. Also most of the farmers who adopted either of the elements of the technology package are small scale farmers, and largely adopted HYV stem (20.06%) than fertilizer (8.72%). This may be because of the cost of HYV stem relative to that of fertilizer (Chima, 2015). Table 3.1 also reveals that high numbers of the respondents (50.87%) did not adopt any of the agricultural technology. This finding is consistent with studies such as Ajayi, (1996), Madukwe, et al. (2002) and Agwu, (2004) that noted low level adoption of agricultural technology in Nigeria in their respective studies. Also, across the farm categories, almost a third of large scale farmers and half of small and medium scale farmers did not adopt any technology. This highlights the main issue of low agricultural productivity in Nigeria and this finding is consistent with studies such as Obasi, et al. (2013), Igwe, (2013) and Agwu, (2004) that noted low productivity, low profitability of farm enterprises; low and nonadoption of agricultural technologies in their respective studies. Across the farm categories, most of the farmers who adopted both technologies (80%) and either of the technologies (83.33% and 76.81%, respectively) are small scale farmers. The table clearly shows that across the farm categories, small farmers are more likely to adopt HYV cassava stem than inorganic fertilizer. Also, only 49.45% of the small scale farmers, 56.10% and 37.50% of the medium and large scale farmers adopted any kind of agricultural technology in the study area. Adoption of agricultural technology as a package is the main principal behind the success of Green Revolution in Asia. This principal is not being applied in the study area and this may be due to the constraints (see section 7 for details) associated with the adoption of agricultural technology in the study area (Chima, 2015). The table clearly demonstrates the key finding, i.e., an inverse farm-size agricultural technology adoption exists in the study area. In other words, the small scale farmers tend to adopt agricultural technology relative to medium and large scale farmers.

4. CROP PRODUCTIVITY AND FARM SIZE RELATIONSHIP AND THEIR INFLUENCING FACTORS This section discusses the result of one of the key hypothesis of inverse farm size– productivity relationship in the study area. It also assesses crop productivity in relation to key influencing factors. This is done with a view to identify the variables that will be included in the bivariate probit model. Yield was chosen as the main yardstick to measure crop productivity level because of the direct effect of agricultural technology adoption has on this variable (Rahman, 2011).

4.1. Crop Productivity by Farm Size The productivity of cassava grown by farmers in the study area and how they relate to their farm-size category is presented in Table 4.1. The table shows that 70.64% of the respondents are in Ebonyi and 29.36% in Anambra states. Analysis of farm-size categories shows that 78.8% are small scale farmers with farm size of 0.1-2.0ha, 11.9% medium scale (2.01-3.0ha) and 9.3% are large scale farmers with ≥ 3.01ha farm size.



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The mean yield for cassava in all areas is 12424.58kg/ha, with 12330.81kg/ha and 12650.18kg/ha for Ebonyi and Anambra states, respectively. The yield level is similar to those estimated by National Programme on Agricultural and Food Security (NPAFS) 2009 Crop Yield Report (NPAFS, 2010) and the reasons for the differences in the states may be related to the level of farm input usage and production practices as noted in Chima, 2015. The one-way ANOVA result shows an inverse relationship between farm size-productivity with small scale farms producing the maximum yield and the large scale farms producing the least. This confirms the hypothesis of inverse farm size-productivity relationship of cassava production in the study area (Chima, 2015). Overall, Anambra state has a higher yield per hectare over Ebonyi state; this may be because farmers in Anambra state have higher mean farm input usage (fertilizer, pesticide, ploughing labour etc.) than those from Ebonyi state and this is reflected in their yield per hectare. This indicates that a higher level of input usage (agricultural technology adoption) given other factors may lead to higher productivity level. Also, as mentioned before, the table shows that small scale farmers have the best yield per hectare in the study area which is consistent with the literature and similar studies like Rahman, (2011); Fabusoro et al, (2010) and Igwe, (2013) who showed that the small scale farms are better managed and productive in developing countries. Table 4.1. Productivity of respondents by farm-size Study Area Ebonyi (243)

Farm Size Category Cassava Yield (Kg/ha) % of Farmer Small 12405.13 74.49 (181) Medium 12244.92 15.64 (38) Large 11906.31 9.88 (24) All 12330.81 70.64 (243) Anambra (101) Small 12724.15 89.11 (90) Medium 12000.00 2.97 (3) Large 12061.81 7.92 (8) All 12650.18 29.36 (101) All Areas Small 12511.08 78.78 (271) (344) Medium 12227.00 11.92 (41) Large 11945.18 9.30 (32) All 12424.58 (344) ANOVA F-value d.f 1.84*** (2, 341) Source: Field Survey 2011 (Chima, 2015) One- way ANOVA using generalised linear mode Note: *** significant at 1% level (p 2.01 ha, 0 otherwise) Gender Dummy (1 if female, 0 otherwise) Note: Exchange Rate: GBP1.00 = Naira 200.00.

--

3.1. Productivity of Gari Produced from Per Ha of Cassava Root Tuber Table 2 presents the results of the productivity analysis of cassava production classified by farm size categories as well as regions. It is clear from Table 2 that productivity of gari processed from per ha of cassava root tuber production varies significantly by farm size categories as well as by regions. The average productivity of gari is highest for marginal farms (2948 kg/ha) and lowest for small farms (2293.2 kg/ha) with a very high standard deviation. This finding points toward the existence of inverse size-productivity relationship in gari processing. Awerije and Rahman (2014) noted presence of inverse size-productivity relationship in cassava production in Nigeria. Amongst the regions, gari productivity is highest in Delta North (3098.6 kg/ha) and lowest in Delta South (1993.0 kg/ha).


208

Brodrick O. Awerije and Sanzidur Rahman Table 2. Productivity of gari processed from one hectare of cassava root tuber production by farm size and region.

Variables

Region Delta Central 2443.80 1156.53 750.00 8333.00

Delta South 1993.01 733.62 1200.00 3920.00

Farm Sizes Category Delta North Marginal Small

Mean 3098.57 Std Deviation 1672.08 Minimum 750.00 Maximum 8000.00 F-value 18.26*** for regional differences (ANOVA) Note:*** = significant at 1 percent level (p < 0.01). Source: Computed from Field Survey, 2008.

2948.69 1510.00 833.00 7333.00

2293.16 1011.63 776.99 8000.00

Overall Medium/Large 2840.53 1769.37 750.00 8333.00 6.47***

2483.62 1297.21 750.00 8333.00

Table 3. Technical, cost and allocative efficiency of gari processing by region and by farm size Regions

Delta Central TE AE CE 0.55 0.64 0.33 0.16 0.11 0.08 0.34 0.33 0.15 1.00 0.87 0.61

Delta South TE AE CE 0.49 0.31 0.65 0.11 0.08 0.09 0.35 0.18 0.35 1.00 0.79 0.90

Mean Std Deviation Minimum Maximum F-value for regional differences (ANOVA) Farm size Marginal Small (1.01 – categories (upto 1.00 ha) 2.00 ha) Mean 0.73 0.66 0.48 0.52 0.66 0.34 Std Deviation 0.18 0.16 0.17 0.14 0.11 0.11 Minimum 0.41 0.34 0.29 0.34 0.32 0.15 Maximum 1.00 1.00 1.00 1.00 1.00 1.00 F-value for farm size differences (ANOVA) Note:*** = significant at 1 percent level (p < 0.01). Source: Computed from Field Survey, 2008.

Delta North TE AE 0.65 0.43 0.19 0.20 0.38 0.05 1.00 1.00

CE 0.65 0.21 0.08 1.00

Medium/Large >2.01) 0.57 0.57 0.33 0.19 0.18 0.15 0.36 0.08 0.05 1.00 1.00 1.00

Overall TE 0.55 0.17 0.34 1.00 26.89***

AE 0.64 0.14 0.08 1.00 0.18

CE 0.35 0.14 0.05 1.00 20.05***

0.64 0.14 0.08 1.00 10.17***

0.35 0.14 0.05 1.00 15.65***

Overall 0.55 0.17 0.34 1.00 23.55***

3.2. Technical, Cost and Allocative Efficiency of Cassava Production Results of efficiency estimates using DEA are presented in Table 3 classified by farm size categories and by regions. The overall mean levels of TE, AE and CE are 55%, 64% and 35% respectively, with significant difference across regions as well as farm size categories. The implication is that there is substantial scope to boost gari productivity by reallocating


Technical, Cost and Allocative Efficiency of Processing Cassava …

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resources to optimal levels, given input and output prices. The TE and CE estimates are higher than cassava production but the AE is lower (Awerije and Rahman, 2014). As with the case of productivity, a clear inverse size-efficiency relationship is observed with marginal farms scoring highest levels of TE, AE and CE. Therefore, based on the results from Table 2 and Table 3, it can be safely concluded that the classic inverse size-productivity as well as size-efficiency relationship exist in gari production in these sample farms of Delta State, Nigeria. Awerije and Rahman (2014) also noted inverse size-efficiency relationship in cassava production in Nigeria. Among the regions, farms located in Delta North performed better than the other two regions. It should be noted that there is no significant difference across regions with respect to AE implying that farmers/processors of all three regions are able to maximize profits given technical efficiency levels.

4. DETERMINANTS OF TECHNICAL, COST AND ALLOCATIVE EFFICIENCY OF CASSAVA PRODUCTION Table 4 presents the parameter estimates of the Tobit model presented in Eq. (4). A total of 12 variables representing farm-specific socio-economic factors were used to identify the determinants of observed technical, cost and allocative efficiencies of cassava production. The model diagnostics revealed that these variables jointly explain variation in farm-specific efficiency levels quite satisfactorily. A total of 19 coefficients out of 36 in three models (excluding the intercept) were significant at the 10% level at least, implying that these factors exert differential effect on the observed measures of technical, cost and allocative efficiencies. Since the Tobit model cannot reveal the magnitude of influence directly, we present the elasticities of the influences of individual socio-economic factors on our three measures of efficiency in Table 5. Table 5 clearly shows that marginal farms are more efficient relative to small and medium/large farms. In fact, small farms are also significantly more allocative and economically efficient as compared to the medium/large farms. The magnitude of the influence is much larger for small farms as compared with the marginal farms. Therefore, taken all these information together, the results econometrically confirm the existence of inverse size-efficiency relationship in gari processing observed in Table 3. Technical efficiency is significantly higher for female processors, which is encouraging. Extension contact, however, is negatively associated with all efficiency measures. The implication is that farmers who have extension advice are using too much of inputs and not achieving the expected yield of gari (hence technical efficiency is lower). And because the farmers are using too much of the inputs, their cost efficiency is low. Also, they are not being able to respond to price information. Awerije and Rahman (2014) noted negative influence of extension contact on TE and CE in cassava production. Aye and Mungatana (2011) also reported negative significant influence of extension contact on technical efficiency in maize production in Nigeria. They concluded that extension services in Nigeria in general have not been effective, especially after the withdrawal of the World Bank funding from the Agricultural Development Project, which is the main agency responsible for extension services (Aye and Mungatana, 2011).


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Table 4. Determinants of technical, cost and allocative efficiencies in gari processing Variables Technical efficiency Constant 0.4730*** Delta North§ 0.1146*** Delta South§ 0.0232 Education 0.0013 Main occupation§ 0.0034 Subsistence pressure -0.0002 Experience 0.0004 Extension contact§ -0.0777*** Training received§ -0.0062 Credit received§ 0.0422** Marginal farms§ 0.1941*** Small farms§ 0.0011 Gender§ 0.0365** Model diagnostic Log likelihood 152.54 Chi-squared(12 df) 101.65*** Number of observations 278 Note:*** = significant at 1 percent level (p < 0.01). ** = significant at 5 percent level (p < 0.05). * = significant at10 percent level (p < 0.10). § = dummy variables.

Cost efficiency 0.2472*** 0.1126*** 0.0495** 0.0020 -0.0154 0.0014 -0.0004 -0.0788*** 0.0087 0.0279* 0.1964*** 0.0699*** 0.0098

Allocative efficiency 0.5515*** 0.0373* 0.0502* 0.0030 -0.0318 0.0026 -0.0004 -0.0599** 0.0155 -0.0007 0.1099*** 0.1127*** -0.0174

210.47 96.34*** 278

163.71 34.87*** 278

Table 5. Elasticities of technical, cost and allocative efficiencies in gari processing Variables Technical efficiency Delta North§ 0.0620*** Delta South§ 0.0145*** Education 0.0156 Main occupation§ 0.0051 Subsistence pressure -0.0015 Experience 0.0106 Extension contact§ -0.0506*** Training received§ -0.0011 Credit received§ 0.0237** Marginal farms§ 0.0367*** Small farms§ 0.0014 Gender§ 0.0271** Number of observations 278 Note:*** = significant at 1 percent level (p < 0.01). ** = significant at 5 percent level (p < 0.05). * = significant at10 percent level (p < 0.10). § = dummy variables.

Cost efficiency 0.0953*** 0.0485*** 0.0379** -0.0360 0.0227 -0.0186 -0.0803*** 0.0024 0.0245* 0.0581*** 0.1332*** 0.0113 278

Allocative efficiency 0.0173*** 0.0270* 0.0316* -0.0408 0.0237 -0.0094 -0.0335** 0.0023 -0.0003 0.0178*** 0.1178*** -0.0111 278

Education significantly influences cost and allocative efficiencies. This is expected because educated farmers are more able to derive correct information regarding prices of inputs and outputs. This enables them to maximize profits and/or able to produce at a lowest cost given the level of technical efficiency and input and output prices. Access of agricultural credit significantly increases technical and cost efficiencies, which is encouraging. Awerije and Rahman (2014) did not find any influence of education and credit on cassava production.



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Location of farmers has an important effect on efficiency scores of gari processing. Farmers located in the Delta North and Delta South are technically, allocatively and economically efficient as compared with farmers in Delta Central. The reasons for such differences may lie with respect to differences in the regional features (e.g., soil conditions, topography, weather, and other unknown factors) and market conditions (e.g., input prices, timely availability, market infrastructure, market competition, etc.). However, Awerije and Rahman (2014) noted differential influence of location on the TE and AE of cassava production.

5. CONSTRAINTS IN PROCESSING GARI INTO CASSAVA Farmers/processors were also asked about the constraints to adding value to cassava through processing. The respondents identified a lack of transportation and adequate information as the top two constraints (Table 6). Approximately 91.5% of the processors agreed that transportation of cassava root tubers from the farm/market to the processing site is costly as the average distance from the farmers/processors to the nearest marketplace is estimated to be 2.93 km (±3.13 km) with a maximum distance of 15 km. Akinnagbe (2010) and Tonukari (2004) also noted distance as a major factor adversely affecting the cost and efficiency of processing. Table 6. Constraints to adding value in cassava through processing Constraints Transportation Difficulties Lack of Adequate Information Too Many Buyers for Limited Raw Materials Lack of Processing Equipment High Cost of Raw Materials/Processing Equipment Lack of Adequate Infrastructure Others Source: Adapted from Rahman and Awerije (2016).

% of processors responding 91.5 91.4 76.6 76.2 72.4 70.5 23.8

Rank 1 2 3 4 5 6 7

CONCLUSION AND POLICY IMPLICATIONS The present study examined the productivity level as well as technical, cost and allocative efficiency of processing cassava into gari as well as determinants of efficiency using a sample of 278 farmers/processors from three regions of Delta State, Nigeria. The study also tested whether the hypothesis of inverse size-productivity and size-efficiency relationships exists in gari processing. Productivity of gari processed from per ha of cassava root tuber varies significantly by farm size categories as well as regions. The average levels of TE, AE, and CE are 55%, 64%, and 35%, respectively, implying that gari production can be boosted substantially by reallocation of resources to optimal levels, given input and output prices. The results also confirmed that gari production in the Delta State, Nigeria demonstrated inverse size-


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productivity as well as size-efficiency relationships. The smallest scale farms, i.e., the marginal farms are the most productive and efficient followed by small farms. Education level significantly influences cost and allocative efficiency of gari processing. Female processors are more technically efficient. Extension contact significantly reduces all efficiency measures which is highly counterintuitive. Farmers located in Delta North and Delta South regions are more efficient relative to Delta Central (the effect of which is subsumed in the constant term). The following policy implications can be drawn for the results of this study. First, investment in education targeted at the farmers/processors will result in significant improvement in cost and allocative efficiencies of gari processing which in turn will increase revenue of the farmers because price of gari is significantly higher than cassava root tuber (Rahman and Awerije, 2014). Second, there is the need for investment in improving cassava processing facilities and utilities. Third, measures to enhance involvement of female processors will increase gari productivity. Fourth, measures to improve access and provision of agricultural credit services through financial institutions as credit significantly influences efficiencies. Fifth, the agricultural extension services in Nigeria needs to be revitalized so that it contributes to improving production efficiency of gari production for all categories of farmers because mean efficiency levels are still very low across the board. This would require investment in developing capacity of the extension workers on new and improved technologies as well as dissemination strategies so that they can effectively serve to benefit the farmers. And sixth, measures are needed to target farmers located in Delta Central to support them to overcome low level of inefficiency relative to Delta North and Delta South. This may take the form of providing infrastructural and marketing support to bring them at par with the facilities and opportunities available for farmers in Delta North and Delta South. Although the policy options are challenging, effective implementation of these measures will increase processing of cassava into gari that could contribute positively to farmers’ revenue in Delta State, Nigeria.

REFERENCES Adejumo, B. A. and Raji, A. O. (2009). An appraisal Gari packaging in Ogbomoso, Southwestern Nigeria. Journal of Agricultural and Veterinary Sciences, 2:120– 126. Akinnagbe, O. (2010). Constraints and strategies towards improving cassava production and processing in Enugu north agricultural zone of Enugu State, Nigeria. Bangladesh Journal of Agricultural Research, 35: 387–394. Amos, O.A., Imam, R.S., Idowu, A. B. and Mubarak, A. A. (2013). Analysis of Cassava product (Gari) marketing in Ekiti Local Government Area, Kwara State, Nigeria. Asian Journal of Agriculture and rural Development, 3: 736–745, 2013. Apata, T.G., Folayan, A., Apata, O.M. and Akinlua, J. (2011). The economic role of Nigeria’s subsistence agriculture in the transition process: implications for rural development. Paper presented at the 85th Agricultural Economics, UK conference at Warwick University during 18-20 April, 2011.



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Asogwa, B.C., Umeli, J.C. and Okwoche, V.A. (2012). Agricultural Policy in Cassava SubSector: Implication for welfare of cassava farmers in Nigeria. British Journal of Science, 6: 81–98. Awerije, B.O. (2014). Exploring the potential of cassava for agricultural growth and economic development in Nigeria. Unpublished PhD thesis. University of Plymouth, UK. Awerije, B.O. and Rahman, S. (2014). Profitability and efficiency of cassava production at the farm-level in Delta State, Nigeria. International Journal of Agricultural Management. 3: 210–218. Aye, G.C. and Mungatana, E.D. (2011). Technological innovation and efficiency in the Nigerian maize sector: Parametric stochastic and non-parametric distance function approaches. Agrekon: Agricultural Economics Research, Policy and Practice in Southern Africa, 50: 1–24. Babatunde, J. (2012). 40% cassava inclusion in flour: Are the miller fighting back? Nigeria Vanguard, June, 2012. Charnes, A., Cooper, W. W. and Rhodes, E. (1978). Measuring the Efficiency of Decision Making Units. European Journal of Operational Research, 2: 429–444. Coelli, T.J., Rahman, S. and Thirtle, C. (2002). Technical, allocative, cost and scale efficiencies in Bangladesh rice cultivation: a non-parametric approach. Journal of Agricultural Economics, 53: 607–626. Denton, F.T., Azogu, I. I. and Ukoll, M.K. (2004). Cassava based recipes for house hold utilization and home generation. AIDU, Federal Department of Agriculture, Abuja, Nigeria. Eke-Okoro, O.N. and Njoku, D.N. (2012). A review of cassava development in Nigeria from 1940-2010. ARPN Journal of Agricultural and Biological Science, 7: 59–65. Färe, R., Grosskopf, S. and Lovell, C.A.K. (1994). Production Frontiers. Cambridge: Cambridge University Press. Farrell, M.J. (1957). The Measurement of Productive Efficiency. Journal of the Royal Statistical Society Series A, CXX (Part 3): 253–290. Gelan, A. and Muriithi, B.W. (2012). Measuring and explaining technical efficiency of dairy farms: a case study of smallholder farms in east Africa. Agrekon: Agricultural Economics Research, Policy and Practice in Southern Africa, 51: 53–74. Hazarika, G. and Alwang, J. (2003). Access to credit, plot size, and cost inefficiency among smallholder tobacco cultivators in Malawi. Agricultural Economics, 29: 99–109. IITA (1990). Cassava in Tropical Africa. A Reference Manual. International Institute for Tropical Agriculture, Ibadan, Nigeria. Kao, C. and Hwang, S.N. (2008). Efficiency decomposition in two-stage data envelopment analysis: An application to non-life insurance companies in Taiwan. European Journal of Operational Research, 185: 418–429. Knipscheer, H., Ezedinma, C., Kormawa, P., Asumugha, G., Mankinde, K., Okechukwu. R. and Dixon, A. (2007). Opportunities in the Industrial Cassava Market in Nigeria. International Institute for Tropical Agriculture (IITA). MANR (2006). Ministry of Agriculture and Natural Resources, Delta State, Nigeria. Agricultural Development Policy Report. McDonald, J.F. and Moffit, R.A. (1980). The uses of Tobit analysis. Review of Economics and Statistics, 61: 318–321.


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Nkonya, E., Pender, J., Kato, E., Omobowale, O., Phillip, D. and Ehui, S. (2010). Enhancing Agricultural Productivity and Profitability in Nigeria. Nigeria Strategy Support Program, Brief # 19. International Food Policy Research Institute, Washington, D.C. Ogundari, K. and Ojo, S.O. (2007). An Examination of Technical, Economic and Allocative Efficiency of Small Farms: The Case Study of Cassava Farmers in Osun State of Nigeria. Bulgarian Journal of Agriculture, 13: 185–195. Ohimain, E.I. (2014).The prospects and challenges of cassava inclusion in wheat bread policy in Nigeria. International Journal of sciences, Technology and Society. 2: 6 –17. Oladeebo, J.O. and Oluwaranti, A.S. (2012). Profit Efficiency among Cassava Producers: Empirical Evidence from South Western Nigeria. Journal of Agricultural Economics and Development, 1: 46–52. Olasore, A.A., Imam, R.S., Idowu, A.B. and Mubarak, A.A. (2013). Analysis of Cassava Product (Garri) Marketing in Ekiti Local Government Area, Kwara State, Nigeria. Asian Journal of Agriculture and Rural Development. 3: 736–745 Rahman, S. and Awerije, B.O. (2014). Marketing efficiency of cassava products in Delta State, Nigeria: A stochastic profit frontier approach”. International Journal of Agricultural Management, 4: 28–37. Rahman, S. and Awerije, B.O. (2015). Technical and scale efficiency of cassava production system in Delta State, Nigeria: an application of Two-Stage DEA approach. Journal of Agriculture and Rural Development in the Tropics and Subtropics, 116: 59–69. Rahman, S. and Awerije, B.O. (2016). Exploring the potential of cassava in promoting agricultural growth in Nigeria. Journal of Agriculture and Rural Development in the Tropics and Subtropics, 117: 149–163. Raphael, I.O. (2008). Technical Efficiency of Cassava Farmers in South Eastern Nigeria: Stochastic Approach. Agricultural Journal, 3: 152–156. Tonukari, N.J. (2004). Cassava and the future of starch. Electronic Journal of Biotechnology, 7: 5–8. Udoh, E.I. and Etim, N–A. (2007). Application of Stochastic Production Frontier in the Estimation of Technical Efficiency of Cassava Based Farms in Akwa Ibom State, Nigeria. Agricultural Journal, 2: 731–735.

BIOGRAPHICAL SKETCHES Dr. Brodrick O. Awerije is an Assistant Chief Agriculture Officer at the Tree Crops Unit, Ministry of Agriculture and Natural Resources, Asaba, Delta State, Nigeria. He is involved in planning, evaluation and implementation of agricultural policies in Delta State. He holds a Master’s Degree in Sustainable Crop Production and a PhD Degree from the University of Plymouth, UK completed in 2004 and 2014, respectively. His main research interest is in the economics of agricultural production and marketing as well as agricultural policies. He has published around the topics in international journals. Dr. Sanzidur Rahman is Associate Professor (Reader) in International Development with the School of Geography, Earth and Environmental Sciences, University of Plymouth, UK. The core area of his research is to improve understanding of the range of factors



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affecting agricultural and rural development in developing economies and to promote their integration into policy and practice. His specialization is in agricultural economics, specifically, on efficiency and productivity measurements, and underlying determinants of technological change, innovation, and diffusion in agriculture. He has published widely on the topic in leading international journals.





Chapter 11

STATUS OF CASSAVA PROCESSING AND CHALLENGES IN THE COASTAL, EASTERN AND WESTERN REGIONS OF KENYA C. M. Githunguri1, , M. Gatheru2 and S. M. Ragwa2 *

1


ABSTRACT Whether cassava can be relied upon as a low cost staple food in urban centres and a source of steady real income for rural households will to a larger extent depend on how well it can be processed and presented to urban consumers in safe and attractive forms at competitive prices to those of cereals. A study was conducted in the coastal, eastern, central, and western regions of Kenya where only the major processors were visited and interviewed randomly using a structured questionnaire. At the coast, 62.5% of the processors were sole proprietors while 37.5% were in partnership. In the eastern region, 66.7% of the processors were sole proprietors while 33.3% were in partnership. In the western region, the only processor interviewed was a company based in Busia. At the coast, 75% of respondents had their own initial capital while in eastern 33% of respondents reported the same. Only 25% and 33% of respondents at the coast and eastern regions, respectively, had acquired their initial capital on credit. In western, the respondent had acquired initial capital through own resources and credit. In the study regions, all processors (100%) met their operating costs. In the coastal region (Mombasa), among the respondents interviewed, 50% made cassava crisps, 17% chapatti and 8% bhajia. In eastern region (Kibwezi), 50% made Nimix (composite flour) and 50% boiled cassava. In western region (Busia), 100% of respondents made composite flour (cassava mixed with other cereals). The major products reported were crisps, fried chips, composite flours (cassava mixed with cereals, legumes, leaves etc). Golden coloured crisps, fiber free cassava and sweet taste were preferred by consumers. Even though processors maintained high standards, none of the processors had their products patented. *

Email: [email protected], Cellphone: +254 726959592.


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C. M. Githunguri, M. Gatheru and S. M. Ragwa Processing of cassava products showed a rising trend which were marketed in supermarkets, direct consumers, retailers and wholesalers. Except for the eastern region, most processors could access raw materials throughout the year. Only a few processors in the coastal region had contractual arrangements with suppliers, whereas there was none in the other regions. Processing equipment were locally fabricated except in the eastern region where they were imported. The processors had reliable sources of power and water. The major constraints included market fluctuations, inadequate supply of cassava, city council regulations, competition from other related products like maize and sweetpotatoes, lack of credit facilities, market and capital, and processing equipment.

INTRODUCTION African farmers grow cassava under field conditions where one or more of the resources are limiting while due to the nature of measurements, most of the research work carried out is under optimum management conditions (Githunguri et al. 2006). Cassava is gaining importance as an industrial crop in several countries within the tropics and especially subSaharan Africa (Ayinde et al., 2004; Azogu et al., 2004; EFDI-Technoserve, 2005; Ezedinma et al., 2005; Githunguri, 1995; Onyango et al., 2006). Safety of cassava products is important and could be affected by agro-ecological zones and genotypes (Githunguri, 2002; Odongo G. O., 2008; Tivana. and Bvochora, 2005). Cassava is the most perishable root crop and deteriorates at ambient temperatures in 2-4 days. Cassava’s twin problems of rapid post-harvest deterioration and cyanide toxicity have been solved through the development of processing methods that increase its shelf life and detoxifies it in various countries but this technology has not taken root in Kenya. Traditional methods like heap fermentation in western Kenya could be mechanized to make them more commercially competitive. In six households in Uganda, it was found that heap fermentation followed by sun-drying of cassava roots reduced the cyanogenic potential from 436 to 20ppm on dry weight basis (Essers et al., 1995). Heap fermentation for four days in three households in Mozambique followed by sun-drying reduced the cyanogenic potential of cassava roots from 660 to 19ppm on dry weight basis (Tivana, 2005). Although heap fermentation is important in reducing total cyanogens in cassava roots, the above levels were still above the World Health Organization (WHO) safe level of 10ppm (FAO/WHO, 1991). The removal of cyanogens by heap fermentation has been found to be less effective than those reported above and that an initial cyanogenic potential of less than 32ppm is required for cassava roots, if the flour is to reach the WHO safe level of 10ppm (Tivana and Bvochoro, 2005). Perhaps the WHO safe level of 10ppm should be revised upwards. The human body, even with very low protein intake, is able to detoxify 12.5mg of cyanide every 24 hours. In a well-nourished adult, the body can detoxify about 50 to 100mg of cyanide every 24 hours (Rosling, 1994). In a population where cassava is the main staple food, a basic daily energy need of 1500 kcal can be obtained from consumption of 500g dry weight of cassava flour. Cassava flour with 25ppm cyanide may be used to prepare a safe cassava meal. Indonesia has set a safe level for cyanide in cassava at 40ppm (Tivana and Bvochoro, 2005). Since some cyanogens will be lost during preparation of a cassava flour meal, the residual cyanogenic potential values of 19 and 20ppm (dry weight) obtained after heap fermentation may be considered safe if the WHO safe level is revised upwards (Essers et al., 1995 and Tivana, 2005). Reported high cyanogenic potential values, up to 150ppm, of heap fermented cassava flour may have been


Status of Cassava Processing and Challenges in the Coastal …

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caused by shortcuts in the fermentation regime, or result from increased root cyanide levels due to drought or use of high cyanide cultivars (Tivana, 2005). Shortcuts in processing commonly occur when food supply is low or the product is for sale. It is important to develop further processing techniques to reduce cyanide, such as a combination of grating cassava roots, fermentation and sun drying or soaking of cassava roots in water and sun drying. Grating and crushing of cassava roots are very effective in removing cyanide because of the contact in the wet parenchyma between linamarin and the hydrolyzing enzyme, linamarase (Rosling, 1994; Githunguri, 2002). In countries like Mozambique, the cassava flour usually comes from plants that have been subjected to two years of drought. Under drought conditions the cyanogenic content of cassava roots is known to increase due to increased water stress on the cassava plant (Bokonga et al., 1994; Githunguri et al., 1998; Githunguri, 2002). This increased water stress may have caused an increase in the linamarin content of the roots. Serious drought may increase the cyanide intake of individuals, if non-efficient processing techniques are used, to such a degree as to precipitate konzo disease epidemic among the consumers as has been observed in Mozambique and parts of Congo (Rosling, 1987). How do we overcome the problem of high cyanide intake levels during drought? Obviously, it is not possible to eliminate the recurrent episodes of drought. Hence, the only possible solution is to reduce the cyanide intake of the populace. Ways to reduce the cyanide intake of the populace include: Improving early warning and food security; encouraging greater use of improved processing methods; improvement of the diet by introduction of other vegetables, pulses and fruits which would help in raising the sulphur containing protein intake which detoxifies cyanide in the blood system as thiocyanate; and a greater use of low cyanide cassava varieties (Cardoso et al., 1999). It seems as if poor soils and droughts increase toxicity (Cock, 1985; Githunguri, 2002). This is of considerable importance to food security programmes focusing on cassava. The very causes of food shortage i.e., drought and poor soils also increase the toxicity of the cassava grown (Rosling, 1987). Prevention of toxic effects from cassava consumption should be based on the fact that incidences of cassava toxicity have been reported only when contributing nutritional deficiencies are present and/or when extraordinary circumstances induce consumption of inadequately processed roots. The nutritional deficiencies are low intake of protein and iodine and the extraordinary circumstances are drought, hunger, war and severe poverty. It must nonetheless be remembered that cassava has saved affected populations in Mozambique and other cassava growing countries like Uganda from starvation under these very circumstances. To advise these populations to reduce cassava cultivation runs counter to common sense (Rosling, 1987). Information on possible acute intoxication must also be included in all forms of cassava promotion programmes, and this problem should thereby be possible to solve or at least control. To try to avoid cassava toxicity by persuading the farmers in these areas to change their staple crops is wishful thinking. New high yielding cassava varieties are an adequate short term solutions, as better food security will enable populations to process the roots adequately. Promotion of better processing is a medium-term solution, but in the long run, farming systems must be developed to increase productivity and to maintain soil fertility. In this way, a stable dietary situation may be created in which the problems with cassava toxicity can be solved. It should be noted that various methods for determination of cyanogens levels in cassava and its products and its metabolite thiocyanate have been developed. One of the


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simplest methods is the use of simple kits for the determination of the total cyanogens, acetone cyanohydrins and cyanide in cassava roots and cassava products (Egan and Bradbury, 1998; Bradbury et al., 1999). Whether cassava can be relied upon as a low cost staple food in urban centres and a source of steady real income for rural households will to a larger extent depend on how well it can be processed into safe forms and on how far it can be presented to urban consumers in an attractive form at prices which are competitive to those of cereals (Nweke et al., 2002). In some large cassava producing countries like Nigeria, the market for some processed products is highly limited to low income groups, while other forms of cassava, e.g., gari have a significant market value for middle and high income consumers. How far the market for cassava may be expended would therefore depend largely on the degree to which the quality of the various processed products can be improved to make them attractive to potential consumers without significant increase in processing costs. Cassava products processing and utilization is done mainly at the subsistence level (Kadere, 2002). At the coastal region, it is men who roast and sell cassava crisps. In both Eastern and Western Kenya, women dominate home-based processing while service processing like milling is male dominated. As processing becomes mechanized men tend to play a leading role. The few home-based processors sell their products directly to consumers or retailers. Tapioca Ltd. in Mazeras is the only factory that employs modern technology to produce cassava flour, starch and glue. Most cassava processing technologies are labour-based facing serious limitations in areas with labour shortages (Mbwika, 2002). Rudimental processing technologies like over reliance on sun-dried methods are rendered impossible during the rainy season. Peeling of cassava roots manually using a knife is time consuming, laborious, difficult to ensure quality control and wasteful. Figure 1 shows a trader processing cassava crisps along Mama Ngina Drive, Mombasa using a crude tool. The fine particles of cassava flour render current milling technologies wasteful. There is need to identify appropriate storage and processing technologies that are cheap, have low losses, improve shelf life and guarantees quality products. Efforts should be made to involve the food processing industry in making ready to eat cassava products available in supermarkets and retail outlets. Due to the enormous potential demand for cassava by the feeds, pharmaceutical, food, paper printing and brewing industries there is need to involve them in the research and development of this sub-sector.

STUDY METHODOLOGY The study was conducted in the coastal (Coast Province), eastern (Central, Nairobi and Eastern Provinces) and western (Nyanza and Western Provinces) regions of Kenya where only the major processors were visited and interviewed randomly. Like in marketing studies it is not possible to predetermine the sample size. Randomly selected cassava processors were interviewed using a structured questionnaire. Data collected included information on characteristics of cassava processors, cassava products, and raw materials, processing equipment, utilities and constraints in cassava processing. The data collected were analyzed using the Statistical Package for Social Sciences (SPSS).



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Figure 1. A trader processing cassava crisps along Mama Ngina Drive, Mombasa. Sales are normally very high during public holidays and weekends.

RESULTS AND DISCUSSION Characteristics of Cassava Processors Characteristics of cassava processors in the three study regions are shown in Table 1. The average number of male employees was two in all the study regions while the average number of female employees was one in the coastal, three in eastern and one in western regions. Labour availability was not a problem in eastern and western regions but was a problem at the coast as reported by 25% of respondents. Concerning employees’ skills on processing, eastern region was leading with 69% of employees being skilled, followed by western (66%) and eastern (63%) regions. At the coast, 62.5% of the processors were sole proprietors while 37.5% were in partnership. In the eastern region, 66.7% of the processors were sole proprietors while 33.3% were in partnership. In the western region, the only processor interviewed was a company based in Busia. Figure 2 shows a motorized cassava chipper that is already in use in Mbeere and coast. At the coast, 75% of respondents had their own initial capital while in eastern 33% of respondents reported the same. Only 25% and 33% of respondents at the coast and eastern respectively had acquired their initial capital on credit. In western, the only respondent had acquired initial capital through own resources and credit. In the three study regions, all processors (100%) met their operating costs.


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Figure 2. Motorized cassava chipper that farmers’ groups already use in Mbeere and coast region.

Table 1. Characteristics of cassava processors

Coast Characteristic Number of employees Males Females Business ownership Sole proprietorship Partnership Company Labour availability Yes No Type of employees Skilled Unskilled Source of initial capital Own resources Credit Own resources & credit Other sources Source of operating capital Own resources Credit Own resources & credit

2 1

Region Eastern Mean

Western

2 2 3 1 Percent of respondents

62.5 37.5 0

66.7 33.3 0

0 0 100

75 25

100 0

100 0

63 37

69 31

66 34

75 25 0 0

33 33 0 34

0 0 100 0

100 0 0

100 0 0

100 0 0



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Cassava Products Table 2 shows the cassava products that were being processed in each of the three regions. In the coastal region (Mombasa), among the respondents interviewed, 50% made cassava crisps (Figure 2), 17% made cassava chapatti and 8% made cassava bhajia. In eastern region (Kibwezi), 50% of respondents made Nimix (composite flour) and 50% boiled cassava. In western region (Busia), 100% of respondents made composite flour (cassava mixed with other cereals). Figure 3 shows dry cassava chips ready for milling into flour in Busia. None of the processors had their products patented.

Figure 2. Processed cassava crisps ready for sale at Mama Ngina Drive, Mombasa. Apart retaild, markets, some are sold to big supermarkets like Nakumatt, Likoni.

Figure 3. Dry cassava chips ready for milling in Matayos Division, Busia District. This is the most common processing method practiced by farmers in this region.

In the coastal region, wholesale price of cassava crisps ranged between 30 and 80 shillings while retail price ranged between 50 and 100 shillings depending on the size of the package (Figure 4). The size of packages ranged between 100g and 250g. Other products


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were chapatti-mandazi, fried cassava, roasted cassava, and bhajia sold at Kshs. 10 per piece respectively. In eastern (Kibwezi), the composite flour commonly known as Nimix was being sold to wholesalers at 60 shillings and to retailers at 80 shillings. In Nairobi, a hotel was selling boiled cassava at 40 shillings per plate, while in western the composite flour was being sold at 50 shillings per kilogram. Except in the coastal region where 25% of respondents experienced closure due to lack of demand, the other regions the products were in high demand. Perception on market trend of cassava-processed products was recorded. Eighty two percent (82%) of respondents at the coast reported that the cassava market was rising while 9% reported a decreasing trend and 9% reported a constant trend.

Figure 4. Processed cassava crisps being sold at Mama Ngina Drive, Mombasa.

Table 2. Cassava products being processed in the coastal, eastern and western regions

Coast Product Nimix Cassava crisps Cassava chapati & mandazi Fried cassava Boiled cassava Bhajia Cassava flour

0 50.0 16.7 25.0 0 8.3 0

Region Eastern Percent respondents 50.0 0 0 0 50.0 0 0

Western 0 0 0 0 0 0 100.0

In eastern, 50% of respondents reported an increasing marketing trend while 50% reported constant trend. In western, the only respondent reported an increasing trend in cassava marketing. The increase in demand at the coast was attributed to high demand of cassava crisps in the supermarkets and tourists along the beach. In the coastal region, 75% of cassava products were sold locally along the beach and 25% in Mombasa city supermarkets. In eastern and western regions, all the cassava products were



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sold locally. Direct clients of cassava products were recorded. In the coastal region 50% were consumers, 25% were retailers and 25% wholesalers. In eastern, 50% of clients were consumers and 50% were retailers. In western, direct clients of the only processor in the area were retailers.

Quality Control Standards for Cassava and Cassava Based Products The minimum quality control standards of cassava and cassava based products varied with region and the product. In the coastal region, where the main product was cassava crisps, cleanliness of crisps (50%), use of fiber free cassava (10%), golden colour of crisps (20%), and sweet taste (20%) control standards were maintained. In the eastern region, the only processor maintained quality standards by indicating the ingredients of the composite flour (Nimix) on the package while in western the processor kept the standards by maintaining high hygiene. To ensure the standards were maintained, processors in the coastal region ensured thorough washing of cassava (30%), use of clean oil (20%) and use of white colour cassava roots (50%). In eastern, the standards were maintained by ensuring the ratios of ingredients were in the right proportions while in western, the standards were maintained by washing the cassava roots thoroughly. The effect of environmental regulations on the production of cassava and cassava-based products was reported by 25% of respondents in the coastal while in eastern and western regions, there were no environmental regulations.

RAW MATERIALS The main raw materials for cassava and cassava-based products varied with region and the products processed. In the coastal region, the main raw materials were cassava roots (50%), cooking oil (25%), charcoal (19%) and salt (6%). The source of raw materials was mainly Kongowea market in Mombasa as shown in Figure 5. In eastern region, the main raw materials were cassava roots, cowpea leaves, pearl millet, pigeon peas, sorghum and sweetpotato leaves all in equal proportions of about 17%. In western region, the main raw material was cassava roots. In both eastern and western regions, the raw materials were sourced locally. In the coastal region, 73% of respondents reported that they obtained raw materials from the source while 27% had the raw materials delivered to them by agents. Similarly, in the eastern region, 50% of respondents reported that they obtained raw materials from the source while 50% had them delivered by agents. In western, the processor collected the raw materials from the source. Fifty percent of respondents at the coastal region reported that they could access raw materials when required while 100% of respondents in eastern reported that they could not access the raw materials when required. In the eastern region the unavailable raw materials are mainly cowpea and sweetpotato leaves during off-season periods. In the western region,


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100% of the respondents could access raw materials when required. Except in the coastal region where 12.5% of respondents had contractual arrangement with suppliers, none of the processors in the other regions had any contractual arrangement. Twenty five percent of the respondents at the coastal region had storage facilities while all respondents in the eastern and western regions had storage facilities.

Figure 5. Cassava tubers for both retail/wholesale market at Kongowea, Mombasa.

PROCESSING EQUIPMENT AND UTILITIES Except in the eastern region (Figure 6) where the equipment was of foreign origin, all the other processing equipment in the three regions were locally fabricated. The average lifespan of the equipment ranged from 8 to 18 years. The average cost of various processing equipment ranged from 38,000 to 1,000,000 K. Shs. At the coastal region, 50% of the equipment was powered by electricity while 50% were both manually and wood powered. The power supply was 67% reliable and 33% unreliable. In eastern region, the equipment was diesel/petrol powered which was highly reliable while in western region the equipment was electrical and also very reliable. At the coastal and eastern regions, 50% of the processors had alternative sources of power. In eastern and western regions, all the processors interviewed had alternative sources of power. The average months of operation of processing equipment ranged from 10 months in the eastern region to 12 months in the coastal and western regions.



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Figure 6. A manual cassava chipper being promoted in Mbeere.

At the coastal region, 83% of the respondents had access to tap water whereas 27% had access to other sources of water (Table 3). In the eastern and western regions, all respondents had access to tap water. In all three regions, the water supply was reliable and processors paid for the water. Table 3. Source of water and reliability for cassava processors in western, eastern and coastal regions Tap water Region Coast Eastern Western

83 100 100

Other sources Reliability % respondents 17 100 0 100 0 100

CONSTRAINTS IN CASSAVA PROCESSING At the coastal region, the major constraints reported were market fluctuations (37.5%), availability of cassava (12.5%), lack of credit facilities (25%), competition from alternative products (12.5%) and city council regulations (12.5%). In the eastern region lack of market (50%) and capital (50%) were the major constraints reported while in the western region, lack of processing equipment (50%) and competition (50%) from other related products like maize and sweetpotatoes were the major constraints.

CONCLUSION The major cassava products reported were cassava crisps, fried chips, composite flours (cassava mixed with cereals, legumes, leaves etc.). Clean and golden coloured crisps, fiber free cassava and sweet taste were preferred by consumers. Processors maintained high standards by thorough washing of cassava, use of clean oil and white cassava roots. In all the


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regions none of the processors had their products patented. Processing of cassava products showed a rising trend in the three regions. The study shows that cassava products were marketed in local outlets like supermarkets, direct consumers, retailers and wholesalers. There is thus need to explore other outlets like manufacturers and export markets. Except for the eastern region, the coastal and western regions most processors could access raw materials throughout the year. A few processors in the coastal region had contractual arrangements with suppliers, whereas none of the processors in the other regions had contractual arrangements. In all three regions the processing equipment were locally fabricated except in the eastern region where the equipment was imported. The three regions had reliable sources of power for running processing equipment. Common sources of power supply included electricity, wood, diesel/petrol and manual. In all three regions the water supply was reliable and processors paid for the water. Generally, the major constraints reported were market fluctuations, inadequate supply of cassava, city council regulations, competition from other related products like maize and sweetpotatoes, lack of credit facilities, market and capital, and processing equipment.

REFERENCES Ayinde, A. O. Dipeolu, K. Adebayo, O. B. Oyewole, L. O. Sanni, J. Adusei and A. Westby. 2004. A cost-benefit analysis of the processing of a shelf stable cassava fufu in Nigeria In: Book of Abstracts of the Sixth International Scientific Meeting of the Cassava Biotechnology Network. CIAT:Cali: Colombia. Azogu I, O Tewe, C Ezedinma and V Olomo. 2004. Cassava Utilisation in Domestic Feed Market, Root and Tuber Expansion Programme. Nigeria. pp 148. Bokonga, M., I. J. Ekanayake, A. G. O. Dixon, and M.C.M.Porto.1994.Genotype environment interactions for cyanogenic potential in cassava. Acta Horticulturae 375.131-139. Bradbury M.G., S. V. Egan and J. H. Bradbury. 1999. Picrate paper kits for determination of total cyanogens in cassava products. Journal of Science, Food and Agriculture. (79) 593601. Cardoso A. P., M. Ernest, J. Clifford and J. H. Bradbury. 1999. High levels of total cyanogens in cassava flour related to drought in Mozambique. Roots; volume 6 issue 2.4-6pp. Cock, J.H. 1985. Cassava. New Potential for a Neglected Crop. Westview Press / Boulder and London, 191pp. Egan, S. V. and J. H Bradbury. 1998. Simple kit for determination of the cynogenic potential of cassava flour. Journal of Science, Food and Agriculture. (76) 39-48. Essers, A.A., Ebong, C., van de Gritt, R., Nout, M. R., Otim-Nape, W. and Rosling, H. 1995. International Journal of Food Science and Nutrition. 46 (2), 126 – 136. EFDI-Technoserve. 2005. Assessment of different models of cassava processing enterprises for the south and South-East of Nigeria, including the Niger Delta. Draft Final Report submitted to IITA-CEDP, March 2005. Ezedinma, C., M. Patino, L. Sanni, R. Okechukwu, P. Ilona, M. Akoroda, A. Dixon. 2005. Investment options in the High Quality Cassava Flour (HQCF) Enterprise. Presented at



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the Stakeholders meeting on Strategies on sourcing high quality cassava flour – H. R. Albrecht Conference Center, IITA, Ibadan, Nigeria, Jan 2005. FAO/WHO. 1991. Joint FAO/WHO Food Standards Programme, Codex Alimentarius Commission, XII, Supplement 4, FAO/WHO, Rome, Italy. Githunguri, C.M., E. G. Karuri, J. M. Kinama, O. S. Omolo, J. N. Mburu, P. W. Ngunjiri, S. M. Ragwa, S. K. Kimani and D. M. Mkabili. 2006. Sustainable Productivity of the Cassava Value Chain: An Emphasis on Challenges and Opportunities in Processing and Marketing Cassava in Kenya and Beyond. A project proposal present to the Kenya Agricultural Productivity Project (KAPP) Competitive Agricultural Research Grant Fund, Research Call Ref No.KAPP05/PRC- CLFFPS –03. KAPP Secretariat 106p. Githunguri, C.M. 2002. The influence of agro-ecological zones on growth, yield and accumulation of cyanogenic compounds in cassava. A thesis submitted in full fulfillment for the requirements for the degree of Doctor of Philosophy in Crop Physiology, Faculty of Agriculture, University of Nairobi, 195pp. Githunguri, C. M, I. J. Ekanayake, J. A. Chweya, A. G. O. Dixon and J. Imungi. 1998. The effect of different agro-ecological zones on the cyanogenic potential of six selected cassava clones. Post-harvest technology and commodity marketing. IITA,71-76pp. Githunguri, C. M. 1995. Cassava food processing and utilization in Kenya. In: Cassava food processing. T. A. Egbe, A. Brauman, D. Griffon and S. Treche (Eds.) CTA, ORSTOM, pp119-132. Kadere, T.T. 2002. Marketing opportunities and quality requirements for cassava starch in Kenya. In Proceedings of regional Workshop on improving the cassava sub-sector, held in Nairobi, Kenya, April 2002, 8-18, pp. 81 - 86. Mbwika, J.M 2002. Cassava sub-sector analysis in the Eastern and Central African region. In Proceedings of regional Workshop on improving the cassava sub-sector, held in Nairobi, Kenya, April 2002, 8-18, pp. 8-18. Nweke, F. I., D. S. C. Spencer and J. K. Lynam. 2002. Cassava transformation. International Institute of Tropical Agriculture. 273p. Odongo G. O. (2008). Analysis of level of toxicity (cyanogenic potential) of various cassava varieties and cassava based products. A Trade Project Report in the Kenya Polytechnic University College Department of Applied Science submitted to the Kenya National Examination Council in partial fulfillment of the requirements for award of Diploma in Food Technology, 35pp. Onyango, C., P. W. Ngunjiri, T. J. Oguta and S. M. Wambugu. 2006. Small-Scale Processing Technologies for Selected Traditional and Horticultural Food Crops in Kenya. Kenya Industrial Research and Development Institute, 166pp. Rosling H.1987. Cassava and food security. A review of health effects of cyanide exposure from cassava and of ways to prevent these effects. A report for UNICEF African Household Food Security Programme 40pp. Rosling, H. 1994. Measuring effects in humans of dietary cyanide exposure from cassava. Cassava Safety. Acta Horticulturae 375, 271-283. Tivana, L. D. 2005. Study of heap fermentation and protein enrichment of cassava. MPhil. Thesis, University of Zimbabwe. 142pp. Tivana, L. D. and Bvochora, J. 2005. Reduction of cyanogenic potential by heap fermentation of cassava roots. Cassava Cyanide Diseases Network News, Issue No. 6 2005, 1p. 5.0 Budget.





Chapter 12

CASSAVA WASTE: A POTENTIAL BIOTECHNOLOGY RESOURCE Aniekpeno I. Elijah* Department of Food Science and Technology, University of Uyo, Uyo, Nigeria

ABSTRACT Although cassava waste may pose serious environmental challenges if not properly disposed of, it could constitute important potential resource if properly harnessed especially by adopting modern biotechnology approach. In this study, plasmids extracted from bacterial isolates associated with cassava waste were explored, using molecular tools, in order to identify genes encoded on the plasmids as well as determine the industrial potentials of the genes borne on the plasmids. Bacterial species isolated from cassava peel (CP) and cassava wastewater (CW) from cassava processing centres in Abeokuta, Nigeria, were identified by aligning their 16S rRNA gene sequences with sequences in the GenBank. Plasmid DNA was extracted from the bacterial isolates, using the Pure Yield Plasmid Miniprep System (Promega, USA) and sequenced. The Open Reading Frame (ORF) Finder was used to identify ORFs on the plasmid DNAs. ORFs were translated and searched against publicly available archives [a non-redundant protein database of GenBank proteins, SWISS-PROT and cluster of orthologous groups (COG)] using the BLAST-P algorithm. Putative genes borne on the plasmids, as well as their products, were deduced from the plasmid nucleotide sequences. Plasmids were found on 14 bacterial isolates. Eight of the isolates (Lactobacillus plantarum, L. brevis, Bacillus coagulans, B. circulans, B. licheniformis, B. pumilus, Enterococcus faecalis and Pediococcus pentosaceus) were from CP while 6 isolates (Lactobacillus fallax, L. fermentum, L. delbruckii, Weisella confusa, Bacillus subtilis and Leuconostoc mesenteroides) were from CW. The gene, tanLpl - encoding tannase was detected on Lactobacillus plantarum plasmid while the gene (bgl1E) which encodes beta- glucosidase was found on Bacillus coagulans and Bacillus circulans plasmids. Other genes detected were hydroxynitrile lyase (HNL) gene on Bacillus licheniformis and Lactobacillus fermentum plasmids; poly-glutamic acid (PGA) synthesis regulator gene on Lactobacillus fermentum plasmid; glutamate synthase gene on Bacillus substilis plasmid; bacteriocin related genes on Lactobacillus fermentum, Lactobacillus fallax and Weisella confusa *

[email protected].


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Aniekpeno I. Elijah plasmids as well as some hypothetical proteins. These enzymes and accessory proteins are all well known for their importance in the food industry. Furthermore, the hypothetical proteins may turn out to be hitherto unknown enzymes for important metabolites or structural proteins. The plasmids could constitute an easy source of genes for mass production of the enzymes and their products. This study, therefore, shows that cassava waste has potentials as an important biotechnology resource, especially for the food industry.

INTRODUCTION Cassava process wastes, including peels, fibrous core and the carbohydrate rich pressing slurry, account for over 50% of the tuber on a wet weight basis (Adeneye and Sunmonu, 1994). Consequently, a large amount of cassava peel is generated annually. Hou et al. (2007) estimated that about 0.3～0.4 tonne of cassava peel is generated when 1 tonne of starch is produced. Indiscriminate disposal of these wastes contributes significantly to environmental pollution and aesthetic nuisance. With the projected total world cassava utilization of 275 million tonnes by 2020 (Arowolo and Adaja, 2012), resulting from ongoing effort at stimulating cassava production and utilization globally, a more challenging environmental concern is undoubtedly anticipated. Although domestic animals such as pigs, ruminants and poultry may feed on the peels, its use for this purpose is often limited, ultimately, by the high level of toxic cyanogenic glycosides which may constitute a health hazard to the animals. Cassava peel is made up of the rough, brown outer part which consists of lignified cellulosic material and the whiter inner portion which consists of parenchymatous material and contains most of the toxic cyanogenic glucosides. The peel is therefore rich in starch and can be used in some industrial processes. Cassava waste products contain almost 70% water and 30% dry weight. In the dry weight fraction, there is 3.5% protein, 10% crude fibre, 11% lignin, 14%, cellulose, and 27% hemicelluloses (Ratnadewi et al., 2016). There is also a small amount of poisonous cyanogenic glycoside present in cassava waste, which must be reduced to below 10 ppm to make it less poisonous. The major nutrients present in cassava waste are sugars and mineral salts. Cassava liquid waste contains nitrogen, sulphur, carbon and minerals (phosphorus, potassium, calcium, magnesium, zinc, manganese, copper, iron and sodium) (Barana, 2000). Hemicelluloses are the second highest component in cassava waste. Bioconversion of hemicelluloses gets high attention because of its benefit in many fields such as the generation of fuel and chemicals, delignification of paper pulp, clarification of juice, digestibility enhancement of animal feedstuffs in addition to the production of emerging prebiotics, i.e., xylooligosaccharides (Saha, 2003; Aachary et al., 2011). In starch processing, pulp waste is the main problem, especially in bigger factories, which produce massive quantities (Ubalua, 2007). Management of this waste is difficult, as it is not easily dried, due to its high moisture and starch contents (Srioth et al., 2000). This solid residue can also be ensiled. The ensiling process contributes to lower the cyanide level to a non-toxic level thus reducing the pH to about 4.0 and allowing lactic acid to build up, and the product can be used as animal feed (Sackey and Bani, 2007). Considerable research has been conducted and is currently being intensified to maximize the use of cassava waste for useful products. The production of animal feed from cassava peels has been well established (Iyayi and Lossel, 2000; Tweyongyere and Katongole, 2002;


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Akinfala and Tewe, 2004). Cassava peels have been enriched in nutrient by fermentation using microorganisms such as yeast and lactic acid bacteria (Oboh, 2006), Aspergillus and Trichoderma species (Obadina et al., 2006). Cassava peels have also been used for the production of functional food (Raupp et al., 2004), ethanol (Adesanya et al., 2008), biofertilizer (Ogbo, 2010), as substrate for mushroom cultivation (Beux et al., 1995; Sonnenberg et al., 2014), and as raw material for xylooligosaccharide production (Ratnadewi et al., 2016). It has also been reported that cassava peels activated carbon is used in the treatment of oil refinery wastewater (Oghenejoboh et al., 2016). Similarly, cassava wastewater has been used for the production of butanol (Wang et al., 2012), organic acids (Pandey et al., 2007), volatile aromatic compounds (Damasceno et al., 2003), biosurfactant (Nitschke and Pastore, 2006) and has even been considered for the production of probiotic beverages (Avancini et al., 2007). However, the status of scientific knowledge in relation to cassava waste microbial genetic resources has been relatively superficial. Cassava waste is a known veritable source of important microorganisms, some of which may have industrial importance. Cassava solid waste degradation is generally initiated by mesophilic heterotrophs, which as the temperature rises, are replaced by thermophilic microorganisms (Ubalua, 2007). Oyeleke and Oduwole (2009) reported 16 strains of Bacillus species isolated from cassava dumpsites. These include Bacillus subtilis, B. macerans, B. megaterium, B. polymyxa and B. coagulans. Similarly, Akpomie et al. (2012) isolated Bacillus subtilis, Bacillus megaterium, Micrococcus luteus, Streptococcus sp., Corynebacterium kutseri, Lactobacillus fermenti, Escherichia coli and Serratia marcescens. Earlier, Cuzin et al. (2001) had reported a new species of the genus Methanobacterium, namely Methanobacterium congolense spp. nov. The strain which is a non-motile, mesophilic, hydrogenotrophic, methanogenic bacterium, was isolated from an anaerobic digester used for the treatment of raw cassava-peel waste in Congo. Fungal species identified in decaying cassava peels include Aspergillus fumigatus and Aspergillus niger (Ogbo, 2010). In addition, Obadina et al. (2006) isolated A. flavus from fermenting cassava solid waste. Cassava starch fermentation wastewater is composed mainly of lactic acid bacteria with predominance of the genera Lactobacillus. Arotupin (2007) identified the microorganisms associated with cassava wastewater to consist of 5 bacteria, 5 moulds and 2 yeasts. The bacteria isolates were Aerococcus viridans, Bacillus substilis, Bacillus] spp. Corynebacterium manihot and Lactobacillus acidophilus, while the fungal (mould) isolates included Aspergillus fumigatus, A. niger, A. repens, Articulospora inflata and Geotrichum candidum. The yeast isolates were Candida utilis and Saccharomyces exiguus. Most of these isolates have been implicated during the processing of cassava into various products (Olowoyo et al., 2000; Akinyosoye et al., 2003). Ahaotu et al. (2011) isolated Alcaligenes faecalis, Lactobacillus plantarum, B. substilis, Leuconostoc cremoris, Aspergillus niger, A. tamari, Geotrichum candidum and Penicillium expansum from cassava wastewater. Out of these, Leuconostoc cremoris, Alcaligenes faecalis, Lactobacillus plantarum and Geotrichum candidum produced linamarase. Similarly, Adamafio et al., (2010) isolated from fermented cassava pulp juice, microorganism such as Aspergillus niger, Aspergillus flavus and Lactobacillus spp. which were capable of reducing the levels of cyanogenic glycosides in cassava peels to non-toxic levels as well as improving the nutritional value of the peels by increasing the protein content appreciably. Recently, Elijah et al. (2014) reported that Bacillus licheniformis and Bacillus substilis are the dominant bacterial species in cassava peel waste while while Lactobacillus fermentum and


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Lactobacillus plantarum are the dominant bacterial species in cassava wastewater. It has also been reported that Aspergillus niger is the dominant fungal species in cassava peel waste while Saccharomyces cerevisiae and Candida krusei are the dominant species in cassava wastewater (Elijah and Asamudo, 2015). It is believed that cassava waste could constitute an important potential biotechnology resource if the diverse cassava waste microbial community is properly exploited especially by adopting modern biotechnology approach. In this study, plasmids extracted from bacterial isolates associated with cassava waste were explored, using molecular tools, in order to identify genes encoded on the plasmids as well as determine the industrial potentials of the genes borne on the plasmids.

MATERIALS AND METHODS Sample Collection Cassava peel (CP waste) from CP waste dumpsites and cassava wastewater (CWW) from CWW discharge outlets were collected from major cassava processing centres in Abeokuta, Ogun State, Nigeria and used for the study.

Isolation, Characterization and Identification of Bacterial Species of Bacteria Bacterial isolates were obtained by seeding serially diluted cassava peel and cassava wastewater samples on appropriate growth medium. Discrete representative colonies were picked from the plates and streaked out on nutrient agar to obtain pure cultures which were transferred to slant and stored in a refrigerator at 4°C. The bacterial isolates were characterized using a culture dependent molecular method.

Bacterial Isolates Genomic DNA Extraction Genomic DNA extraction from bacterial isolates was also carried out using the DNeasy Blood and Tissue Extraction Kit (Qiagen, USA) following the protocol provided by the manufacturer. Overnight cultures grown in tryptone-soy broth (TSB) were centrifuged for 10 min at 5000 x g, to harvest cells. The pellet was washed 3 times in TE buffer, resuspended in enzymatic lysis buffer (containing 2 mg/ml lysozyme, 25 Mm Tris HCl pH 8, 10 Mm EDTA, 25% sucrose) and incubated at 37°C for 30 min in an incubator (Uniscope SM9052, Surgifriend Medicals, England). Proteinase K and extraction buffer were added, mixed by vortexing and incubated at 56°C in a water-bath (Uniscope SM101 Shaking Water bath, Surgifriend Medicals, England) for 30 min. The DNA was precipitated with ethanol (96 – 100%, v/v) and transferred into the DNeasy Mini spin column for binding of DNA to the column, washed with two different 500 µl washing buffers and eluted with 200 µl elution buffer. The resulting DNA was stored at -20°C.



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Plasmid DNA Extraction Plasmid DNA was extracted from bacterial isolates using the Pure Yield Plasmid Miniprep System (Promega, USA) according to the manufacturer’s instruction. Pure isolates were inoculated in tryptone-soy broth (TSB) and incubated overnight at 37°C. Cells were pelleted (by centrifuging for 10 min at 5000 x g and the supernatant discarded) and resuspended in sterile distilled water prior to lysis. The bacteria culture (600 µl) was transferred into a 1.5 ml microcentrifuge tube. Cell lysis buffer (100 µl) was added and mixed by inverting the tube 6 times. Colour change of the solution from opaque to clear blue indicated complete lysis. About 350 µl of cold (+8°C) neutralization solution was added and mixed thoroughly by inverting the tube. The sample turned yellow when neutralization was complete, forming a yellow precipitate. The resulting suspension was centrifuged at 14,000 x g for 3 min and the supernatant (~900 µl) transferred to a Pure Yield Minicolumn placed into a Pure Yield collection tube and centrifuged at 14,000 x g in a microcentrifuge for 15 s. The flow-through was discarded and the minicolumn was placed in the same Pure Yield collection tube. Endotoxin Removal Wash (200 µl) was added to the column and centrifuged at 14,000 x g in a microcentrifuge for 15 s. About 400 µl of Column Wash Solution was added to the column centrifuged at 14,000 x g in a microcentrifuge for 30 s. The minicolumn was transferred to a clean 1.5 ml microcentrifuge tube; 30 µl of Elution Buffer was added directly to the minicolumn matrix and allowed to stand for 1 min at room temperature (29 - 32°C) after which it was centrifuged at 14,000 x g in a microcentrifuge for 15 s to elute the plasmid DNA which was stored at -20°C.

Amplification of the 16S rRNA Genes The 16S rRNA gene from bacterial isolates’genomic DNA was amplified by Polymerase Chain Reaction (PCR) using bacterial universal primers (27F – AGAGTTTGAT CCTGGCTCAG and 1492R – GGTTACCTTGTTACGACTT). The amplification was carried out in a Techne TC-412 Thermal Cycler (Model FTC41H2D, Bibby Scientific Ltd, UK) in a 50 µl reactions containing 25 µl of 2 X PCR Master Mix (Norgen Biotek, Canada), 1.5 µl of template DNA (0.5 µg), 1 µl of both forward and reverse primers (2.5 µM of each) and 21.5 µl of nuclease free water in a PCR tube added in that order. PCR was carried out at an initial denaturation step at 94°C for 2 min, followed by 30 cycles at 94°C for 30 sec, 52°C for 30 sec and 72°C for 2 min, and a final extension step at 72°C for 5 min. PCR products (amplicons) as well as plasmid DNA were separated by electrophoresis on a 1% agarose TAE gel containing ethidium bromide and visualized by UV transillumination (Foto/UV 15, Model 3- 3017, Fotodyne, USA).

DNA Sequencing and Analysis The bacteria 16S rRNA gene from the genomic DNA as well as the plasmid DNA were sequenced with 518F and 800R primers using ABI PRISM Big Dye Terminator cycle sequencer (Macrogen, USA). The gene sequences obtained were compared by aligning the


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result with the sequences in GenBank using the Basic Local Alignment Search Tool (BLAST) search program at the National Centre for Biotech Information (NCBI). The Open Reading Frame (ORF) finder (NCBI) was used to identify protein coding regions in the plasmid DNA sequence.

Plasmid Analysis Nucleotide sequence analysis of plasmids extracted from some of the bacterial isolates showed that cassava waste has great potentials as important biotechnology resource for industrial applications as novel putative and useful genes were found on their plasmids. The putative genes carried on the plasmids of bacterial isolates from cassava waste, as well as their products, as deduced from plasmid nucleotide sequences are presented in Table 1. Out of the 52 bacterial isolates obtained from both cassava peel and cassava wastewater, plasmids were found only on 14 isolates. Eight of the isolates (Lactobacillus plantarum, L. brevis, Bacillus coagulans, B. circulans, B. licheniformis, B. pumilus, Enterococcus faecalis and Pediococcus pentosaceus) were obtained from cassava peel while 6 isolates (Lactobacillus fallax, L. fermentum, L. delbruckii, Weisella confusa, Bacillus subtilis and Leuconostoc mesenteroides) were obtained from cassava wastewater. Two open reading frames (ORF) encoding two genes were found on plasmid from Lactobacillus plantarum isolated from cassava peel: a hypothetical protein (ORFs 2: 14121612), with an expect value (E-value) of 3e-25, whose region was identical (100% identity) to the conserved hypothetical protein region of Lactobacillus hilgardii ATCC 8290 (accession no. ZP_03954203.1) and the tanLpl gene (ORFs 1: 1 – 303) which encodes tannase (E-value: 3e-38). The open reading frame of the tanLpl gene, spanning 303 bp, encoded a 100 -aminoacid protein that showed 95% similarity to the tannase of Lactobacillus plantarum (BAG68453.1) with several commonly conserved sequences. The gene tanLpl, encoding a possibly novel tannase enzyme (tanLpl), has been identified in Lactobacillus plantarum ATCC 14917 isolated from pickled cabbage, cloned and expressed in E. coli (Iwamotoa et al., 2008). However, the amino acid sequence of the tanLpl (469 aa) reported by the authors was longer than 100aa reported in the present study, although it shared several highly conserved sequences, likely to include catalytic residues, with other known tannase. L. plantarum isolated from various fermented plant materials have also been shown to possess tannase activity (Nishitani et al., 2004). Tannase, or tannin acyl hydrolase (E.C. 3.1.1.20), catalyzes the hydrolysis of the ester bond and the depside bond present in hydrolyzable tannins such as tannic acid to release glucose and gallic acid (Lekha and Lonsane, 1997). The gallic acid, although most commonly used in the pharmaceutical industry for the production of the antibacterial drug trimethoprim (Bajpai and Patil, 1996), is also used as an important substrate for the synthesis of propyl gallate, an antioxidant, in the food industry (Lekha and Lonsane, 1997), and catechin gallates (Raab et al., 2007). A number of innovative applications of tannase have been reported, such as in the enhancement of antioxidant activity and in vitro inhibitory activity against the N-nitrosation of dimethylamine in green tea (Lu and Chen, 2007; 2008), the production of derivatives from prunioside-A with anti-inflammatory activities (Jun et al., 2007), the hydrolysis of epigallocatechin gallates (Battestin et al., 2008), and enzymatic treatment for the nutritive



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utilization of proteins and carbohydrates from peas (Urbano et al., 2007). Additionally, it is used to reduce the antinutritional effects of poultry and animal feed along with food detanification and industrial effluent treatment (Belmares et al., 2004). Tannic acid - an anti-nutrient which precipitates protein, thereby inhibiting its absorption and utilization, is present in cassava peel and in the tuber itself (Osuntogun et al., 1987). The presence of the organism carrying the gene encoding tannase in cassava waste could imply that this anti-nutrient can be eliminated naturally form cassava tuber and peel by fermentation. This gene could be cloned and successfully overexpressed in Escherichia coli, thereby solving the problem of limited availability of the enzymes for large scale industrial application. The plasmid from Bacillus coagulans carried two functional genes; a replication protein, RepA (ORFs 2: 473 – 775) with an E-value of 2e-58 and the bgl1E gene (ORFs 1: 1 - 249) which encodes beta-glucosidase (E-value of 1e-36). The replication protein was 95% identical to the replication protein region of Lactobacillus plantarum (accession no. YP_002117539.1) while the beta-glucosidase had 89% similarity to beta-glucosidase from an uncultured bacterium (accession no. ACM91556.1), with several commonly conserved sequences. Two novel genes (bgl1D and bgl1E) which encode 172- and 151-aa peptides respectively, have been identified by function-based screening of a metagenomic library from uncultured soil microorganisms and their corresponding recombinant putative beta-glucosidases biochemically characterized (Jiang et al., 2011). Lactobacillus brevis carried a plasmid with two ORFs (2 and 3). ORF 2 (26 - 850) translated into an HNL gene encoding hydroxynitrile lyase (E-value: 0.0). This region was closely identical (99% identity) to the (S)-hydroxynitrile lyase region of Manihot esculenta (accession no. P52705.3). ORF 3 (1005 – 1364) translated into abp118a gene encoding bacteriocin alpha peptide (E- value; 1e-35) which was 100% identical to abp118a acid bacteriocin alpha peptide from Lactobacillus salivarius UCC118 (YP _536804.1). Lactobacillus fermentum plasmid had 3 ORFs (1, 2 and 3) encoding HNL (77- 922) for hydroxynitrile lyase (E-value: 0.0), DNA-binding protein, Ptr (1157-1497) with an E- value of 4e-78 and a polyglutamic acid (PGA)-synthesis regulator, pgsR (1 - 207) with an E-value of 8e-20. The HNL gene was 100% identical to a chain A crystal structure of hydroxynitrile lyase from Manihot esculenta in complex with substrates acetone and chloroacetone, 1DWO. Ptr was 100% identical to DNA-binding protein Ptr, from Bacillus subtilis (NP_049444.1) while pgsR was 98% identical to PGA-synthesis regulator PgsR from Bacillus amyloliquefaciens (YP_003600424.1). The detoxification of cyanogenic glycosides is a two step process involving first a deglycosylation (regulated by β -glucosidases) resulting in a cyanohydrin. Finally, HNLs catalyse the last step of cyanogenesis, i.e., the breakdown of the cyanohydrin to release the corresponding aldehyde or ketone and cyanide. Beta-glucosidase (β-D-glucoside glucohydrolase, EC 3.2.1.21) catalyzes the hydrolysis of β-glucosidic linkages of various oligosaccharides and glycosides to form glucose and a shorter/debranched oligosaccharide. It is a key rate-limiting enzyme of the cellulose hydrolyzing system in bacteria and fungi. As cassava contains various amounts of cyanogenic glucosides, bacteria with these enzymes can hydrolyse linamarin to glucose and acetone cyanohydrin and use the glucose for their


Table 1. Putative genes and their products deduced from plasmid nucleotide sequence Source

Gene name

ORF position (range) 1 - 303

Length (aa)

Lactobacillus plantarum

tanLpl

1412- 1612

66

1 - 249

82

RepA

473 – 775

100

Hnl

26 - 850

274

abp118a

1005 – 1364

108

Hnl

77- 922

281

Ptr

1157-1497

114

pgsR

1 - 207

68

1 -1793

598

Bacillus coagulans bgl1E

Lactobacillus brevis

Lactobacillus fermentum

Lactobacillus fallax

100

Best hit (Organism, Genbank accession number) tannase (Lactobacillus plantarum, BAG68453.1) Conserved hypothetical protein (Lactobacillus hilgardii ATCC 8290, ZP_03954203.1) beta-glucosidase (uncultured bacterium, ACM91556.1|) Replication protein (Lactobacillus plantarum, YP_002117539.1) (S)-hydroxynitrile lyase (Manihot esculenta, P52705.3) Abp118 bacteriocin alpha peptide (Lactobacillus salivarius UCC118, YP _536804.1) A chain A, crystal structure of hydroxynitrile lyase from Manihot esculenta in complex with substrates acetone and chloroacetone, 1DWO DNA-binding protein Ptr (Bacillus subtilis, NP_049444.1) PGA-synthesis regulator PgsR (Bacillus amyloliquefaciens, YP_003600424.1) glutamate synthase subunit beta (Bacillus subtilis subsp. subtilis str. 168, ZP_03591582.1)

% identity

E- value

Proposed identity of gene product

95

3e-38

Tannase

100

3e-25

Hypothetical protein

89

1e-36

Beta-glucosidase

95

2e-58

Replication protein

99

0.0

100

1e-35

Hydroxynitrile lyase Bacteriocin alpha peptide

100

0.0

Hydroxynitrile lyase

100

4e-78

DNA-binding protein Ptr

98

8e-20

100

0.0

Polyglutamic acid (PGA)-synthesis regulator Glutamate synthase


Source

Gene name

Lactobacillus fallax

Bacillus licheniformis

Lactobacillus delbrueckii

ORF position (range) 207 – 395

Length (aa)

1028-1246

72

1306-1701

131

1 – 834

277

62

Lactobacillus delbrueckii

LSL_1918

1024-1305

93

Bacillus circulans

Dtur_1677

1 – 885

294

DICTH_1569

1068 – 1205

45

abp118b

47 - 253

68

AbpIM

93 – 293

66

Weisella confusa

Best hit (Organism, Genbank accession number) hypothetical protein CaO19.6256 (Candida albicans SC5314, XP_718844.1) glutamate synthase subunit beta (Bacillus licheniformis DSM 13, YP_079323.1) putative thioredoxin protein (Bacillus licheniformis, NP_955636.1) bacteriocin secretion accessory protein (Lactobacillus salivarius ACS-116-V-Col5a, ZP_07205827.1) bacteriocin-like prepeptide (Lactobacillus salivarius UCC118, YP_536805.1) glycoside hydrolase family protein (Dictyoglomus turgidum DSM 6724, YP_002353563.1) 6-phospho-beta-glucosidase BglT (Dictyoglomus thermophilum H-6-12, YP_002251384.1) Abp118 bacteriocin beta peptide (Lactobacillus salivarius UCC118, YP_536803.1) AbpIM bacteriocin immunity protein (Lactobacillus salivarius UCC118, YP_536802.1)

% identity

E- value


53

3e-10


100

5e-16

Glutamate synthase

100

2e-53

Putative thioredoxin protein

98

0.0

Bacteriocin secretion accessory protein

100

7e-40

Bacteriocin-like prepeptide

99

0.0

Glycoside hydrolase family protein

79

4e-13

6-phospho-betaglucosidase

90

9e-13

Bacteriocin beta peptide

100

3e-06

Bacteriocin immunity protein


Table 1. (Continued) Source

Gene name

ORF position (range) 1 – 240

Length (aa)

Bacillus subtilis

LSL_1822

313 – 507

64

BMQ_pBM60021

1 – 393

130

pPER272_0129

911 – 1038

43

Pediococcus pentaceus

parA

1 – 656

219

Enterococcus faecalis

KPHS_25200

1 - 986

329

Leuconostoc mesenteroides

LEUM_A23

1 - 659

220

Bacillus pumilus

79

Best hit (Organism, Genbank accession number) hypothetical protein LSL_1822 (Lactobacillus salivarius UCC118, YP_536710.1) conserved hypothetical protein (Lactobacillus salivarius ATCC 11741, ZP_04009819.1) glycosyl transferase, group 2 family protein (Bacillus megaterium QM B1551, YP_003569785.1) RNA chaperone Hfq (Bacillus cereus, YP _001966673.1) plasmid partition protein homolog ParA (Corynebacterium glutamicum, NP_862298.1) unnamed protein product (Klebsiella pneumoniae subsp. pneumoniae HS11286, YP_005226820.1 site-specific recombinase, DNA invertase Pin related protein (Leuconostoc mesenteroides subsp. mesenteroides ATCC 8293, YP_794196.1)

% identity

E- value


96

2e-34


94

7e-13


100

1e-86

Glycosyl transferase,

100

4e-21

RNA chaperone

88

3e-123

Plasmid partition protein

91

0.0

Putative dehydrogenase

85

2e-122

site-specific recombinase, DNA invertase Pin related protein



241

metabolism. Previous studies have demonstrated the potentials of Bacillus spp. (Ugwuanyi et al., 2007), and Lactobacillus spp. (Adamafio, 2010), for the detoxification of cyanogenic glycoside. The genes encoding these enzymes being borne on the plasmid can easily be manipulated for industrial applications. The polyglutamic acid (PGA) synthesis regulator, pgsR on the Lactobacillus fermentum plasmid is of great significance. PGA is a water-soluble, anionic, biodegradable, and edible biopolymer produced predominantly by bacteria belonging to Bacillus spp., such as B. licheniformis, B. subtilis, B. megaterium, B. pumilis, B. mojavensis and B. amyloliquefaciens (Bajaj and Singhal, 2011). It has multifarious potential applications in foods, pharmaceuticals, healthcare, water treatment and other fields. Sakai et al. (2000) showed that the addition of PGA had a de-bittering effect to substances having a bitter taste (amino acids, peptides, quinine, caffeine, minerals, etc.), is used for prevention of aging and improvement of textures of starch-based bakery products and noodles, and as an ice cream stabilizer. In addition, PGA is reported to increase bioavailability of calcium by increasing its solubility and intestinal absorption (Tanimoto et al., 2007). Till date, there is no report of production of PGA by Lactobacillus fermentum. The presence of polyglutamic acid (PGA) synthesis regulator gene in Lactobacillus fermentum plasmid seems to suggest the possible presence of PGA synthase, the gene that drives the synthesis of PGA. Ordinarily, a regulatory gene controls the expression of the gene. This is worth further investigation, considering the numerous applications of PGA. Plasmid from Lactobacillus fallax carried 2 genes. These included ORF 1(1- 1793) which encoded glutamate synthase (E-value: 0.0), 100% identical to glutamate synthase subunit beta from Bacillus subtilis subsp. subtilis str. 168 (ZP_03591582.1) and a hypothetical protein (ORF 2: 207 – 395), with an E- value of 3e-10, which was 53% identical to hypothetical protein CaO19.6256 from Candida albicans SC5314, (XP_718844.1). Two genes were also found on Bacillus licheniformis plasmid. The first one was a putative thioredoxin protein (ORF 1:1306 - 1701) with an E-value of 2e-53, which was 100% identical to putative thioredoxin protein from Bacillus licheniformis (NP_955636.1) while the second one was a glutamate synthase gene (ORF 2:1028 - 1246) with an E-value of 5e-16, 100% identical to glutamate synthase subunit beta from Bacillus licheniformis DSM 13 (YP_079323.1). Glutamate synthase is the enzyme responsible for biosynthesis of glutamate, an essential component of the major pathway for ammonia assimilation and a direct nitrogen donor for the biosynthesis of amino acids and other nitrogen-containing compounds. Among the metabolites of a bacterial cell, glutamate is of central importance, since it provides the link between carbon and nitrogen metabolism (Commichau et al., 2008). In Bacillus subtilis, glutamate is synthesized exclusively by the reductive amination of α-ketoglutarate by the enzyme glutamate synthase (Belitsky, 2002). This enzyme produces two molecules of glutamate from α- ketoglutarate and glutamine, the primary product of ammonium assimilation. Of these two molecules, one remains in the cycle, whereas the second can be used for protein biosynthesis or transamination reactions to provide the cell with nitrogencontaining compounds. In addition, glutamate is used in the manufacture of monosodium glutamate-an important food flavour enhancer, indicating that cassava waste has great potentials as important biotechnology resource for the food industry. The plasmid from Lactobacillus delbrueckii had 2 ORFs (1-834 and 1024-1305) encoding bacteriocin secretion accessory protein (E-value: 0.0) which was 98% identical to bacteriocin secretion accessory protein from Lactobacillus salivarius ACS-116-V-Col5a


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Aniekpeno I. Elijah

(ZP_07205827.1) and a bacteriocin-like prepeptide (E-value:7e-40), 100% identical to bacteriocin-like prepeptide from Lactobacillus salivarius UCC118 (YP_536805.1) respectively. Similarly, Bacillus circulans plasmid had 2 ORFs (1 and 3) encoding a glycoside hydrolase family protein (ORF1:1 – 885; E-value: 0.0) which was 99% identical to glycoside hydrolase family protein from Dictyoglomus turgidum DSM 6724 (YP_002353563.1) and a 6-phospho-beta-glucosidase (ORF 3: 1068 – 1205; E-value: 4e-13) which was 79% similar to 6-phospho-beta-glucosidase BglT from Dictyoglomus thermophilum H-6-12 (YP_002251384.1). Two genes were also found on Weisella confusa plasmid; Abp118 bacteriocin beta peptide (ORF2: 47 – 253; E-value: 9e-13) which was 90% similar to Abp118 bacteriocin beta peptide from Lactobacillus salivarius UCC118 (YP_536803.1) and AbpIM bacteriocin immunity gene (ORF 3:93– 293; E-value: 3e-06) which was 100% identical to AbpIM bacteriocin immunity protein from Lactobacillus salivarius UCC118 (YP_536802.1). Bacteriocin related genes, including bacteriocin alpha peptide, bacteriocin secretion accessory protein, bacteriocin-like prepeptide, bacteriocin beta peptide and bacteriocin immunity protein are most often encoded on plasmids but are occasionally found on the chromosome (Riley, 2009). The activity of some bacteriocins depends on the complementary role of the alpha- and beta- peptides. The immunity gene encodes a protein conferring specific immunity to the producer cell that acts by binding to and inactivating the toxin protein, while the accessory protein appears to be required for secretion of the bacteriocin. The presence of these genes further revealed the hidden potentials in cassava waste. Previously, Lactobacillus lactis and Lactobacillus plantarum isolated from vegetable waste had been reported to be potent producers of bacteriocins (Lade et al., 2006). Similarly, Lactobacillus fermentum (Riaz et al., 2010), Lactobacillus fallax (Kostinek et al., 2005) and Weisella confusa (Ayeni et al., 2011) have been shown to produce bacteriocins. Bacillus substilis plasmid carried a gene for a hypothetical protein (ORF 1: 1 – 240; Evalue: 2e-34), a region closely identical (96% similarity) to the hypothetical protein LSL_1822 region of Lactobacillus salivarius UCC118 (YP_536710.1) and a conserved hypothetical protein (ORF 1: 313- 507; E-value: 7e-13) which was 94% identical to the conserved hypothetical protein from Lactobacillus salivarius ATCC 11741 (ZP_04009819.1). Similarly, Bacillus pumilus plasmid carried two genes encoding a glycosyl transferase, group 2 family protein (ORF 1: 1 – 393; E-value: 1e-86) which was 100% identical to the glycosyl transferase group 2 family protein from Bacillus megaterium QM B1551 (YP_003569785.1), and an RNA chaperone (ORF 2: 911 – 1038; E-value: 4e-21), a region identical (100% identity) to the RNA chaperone Hfq of Bacillus cereus (YP_001966673.1). The Pediococcus pentaceus plasmid carried only one functional gene, a plasmid partition protein homolog, ParA (ORF1: 1 – 656; E-value: 3e-123). This region was somewhat identical (88% similarity) to the plasmid partition protein homolog ParA region of Corynebacterium glutamicum (NP_862298.1). Similarly, Enterococcus faecalis plasmid had an ORF (1:1 – 986; E-value: 0.0) which encoded an unnamed protein product. This region was 91% identical to an unnamed protein product region of Klebsiella pneumoniae subsp. pneumoniae HS11286 (YP_005226820.1). Also, the Leuconostoc mesenteroides plasmid had an ORF (1:1 – 659; Evalue: 2e-122) encoding a site-specific recombinase, DNA invertase Pin related protein, 85% identical to the site-specific recombinase, DNA invertase Pin related protein from Leuconostoc mesenteroides subsp. mesenteroides ATCC 8293 (YP_794196.1).



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The gene encoding site-specific recombinase borne on the plasmid of Leuconostc mesenteroides isolated from cassava wastewater could be a useful tool for DNA recombination technology. Site-specific recombinases are able to recombine specific sequences of DNA with high fidelity without the need for cofactors (Dymecki, 2000). For this reason, they have been used effectively to create gene deletions, insertions, inversions, and exchanges in exogenous systems (Branda et al., 2004). This technology is quite attractive since it enables the precise integration of transgenes of interest into pre-defined integration sites, thereby allowing the prediction of the expression properties of a genetically manipulated cell. Lack of control over the copy number and position of the integrated DNA molecules in the chromosome(s) results in an unpredictable transgene expression pattern (Wirth et al. 2007). This affects not only the level of transgene expression and long-term stability but may also cause undesired disturbance of nearby host genes. Though most described site-specific recombinases are from prokaryotes, they are not limited to prokaryotes (Wirth et al. 2007), and so could function in eukaryotes, providing a useful biotechnological tool. Other genes isolated encoded on the bacterial plasmids such as replication protein (Rep A), DNA-binding protein, putative thioredoxin, glycoside hydrolase family protein, glycosyl transferase, RNA chaperone, plasmid partition protein (parA), putative dehydrogenase, sitespecific recombinase, DNA invertase Pin related protein, and many hypothetical proteins whose functions are unknown play vital roles in maintaining the integrity of the cell. The unknown proteins are subjects for further research, to determine their identity and potential uses. Replication protein (Rep A) is one of the DNA replication accessory proteins which are universally found in nature. It is an essential protein for viability of the cell that participates in DNA replication, DNA repair (nucleotide excision repair), and homologous DNA recombination (Longhese et al,. 1994). DNA-binding proteins (DBP) are proteins that are composed of DNA-binding domains and thus have a specific or general affinity for either single or double stranded DNA. They include transcription factors which modulate the process of transcription, various polymerases, nucleases which cleave DNA molecules, and histones which are involved in chromosome packaging and transcription in the cell nucleus. They can incorporate such domains as the zinc finger nucleases, the helix-turn-helix, and the leucine zipper (among many others) that facilitate binding to nucleic acid. DBP are critically important in the regulation of a variety of essential cellular processes, such as genome replication, gene transcription, cell division, and DNA repair (Liu et al., 2012). Thioredoxin are a group of small (10- to 12-kDa) ubiquitous proteins which have a conserved CXXC catalytic site that undergoes reversible oxidation/reduction of both cysteine residues. The thioredoxin system plays several key roles in maintaining the redox balance inside the cell and responding to oxidative stress in all three domains of life (Hirt et al., 2002). In addition to functioning as an electron donor, thioredoxin is an essential component of the T7 DNA polymerase (Ye et al., 2007). RNA chaperones are proteins that interact with RNA molecules to solve the RNA folding problem (Schroeder et al., 2004), by preventing misfolding or by resolving misfolded species, thereby ensuring that RNA is accessible for its biological function. This is in contrast to proteins that help protein or RNA folding by catalyzing steps along the folding pathway or by stabilizing the final folded protein or RNA structure (Herschlag, 1995). RNA molecules have


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the tendency to fold into diverse secondary structures, and these alternative misfolded structures have to be resolved in order for the RNA molecules to function normally. Plasmid partition protein (parA) is critical to the survival of any bacterial species as it is required for the faithful inheritance of genetic information to the offspring. The stable maintenance of a plasmid in a bacterial cell depends on effective replication followed by partition of newly synthesized plasmid particles between newborn cells. Low copy number bacterial plasmids fulfill this requirement by encoding partitioning systems, similar to those found in their hosts. Plasmid partitioning systems have been divided into types I–III, based upon the homology of their filament-forming proteins to known protein families (Salje, 2010). Type I plasmid partitioning systems is distinguished by two proteins, often called ParA and ParB. The ParA-like protein is an ATPase, and the ParB-like protein is a site-specific DNA-binding protein that recognizes the partition site(s). ParA and ParB are required for two distinct functions in P1 partition: regulation of par gene expression and physical segregation of the plasmids (Bignell and Thomas, 2001). ParA’s regulatory role is as the transcriptional repressor of the par operon. ParB improves the repressor activity of ParA and is therefore a co-repressor.

CONCLUSION This study has shown that cassava waste, on account of its rich microbial genetic resources, is an important biotechnology resource with great industrial potential that could be exploited for the benefit of mankind. The enzymes and accessory proteins are of great significance to the food industry. The hypothetical proteins may turn out to be hitherto unknown enzymes for important metabolites or structural proteins. Therefore, these plasmids constitute an easy source of genes for mass production of the enzymes and their products, using appropriate host cells such as E. coli.

REFERENCES Aachary, A. A. and Prapulla, S. G. (2011). Xylooligosaccharides (XOS) as an emerging prebiotic: microbial synthesis, utilization, structural characterization, bioactive properties and applications. Comprehensive Reviews in Food Science and Food Safety, 10: 2–16. Adamafio, N. A., Sakyiamah, M. and Tettey, J. (2010). Fermentation in cassava (Manihot esculenta Crantz) pulp juice improves nutritive value of cassava peel. African Journal of Biochemistry Research, 4(3): 51-56. Adeneye, J. A. and Sunmonu, E. M. (1994). Growth of male WAD sheep fed cassava waste or dried sorghum brewer's grain as supplements to tropical grass/legume forage. Small Ruminant Research, 13: 243-249. Adesanya, O. A., Oluyemi, K. A., Josiah, S. J., Adesanya, R. A., Shittu, L. A. J., Ofusori, D. A., Bankole, M. A. and Babalola, G. B. (2008). Ethanol production by Saccharomyces cerevisiae from cassava peel hydrolysate. The Internet Journnal of Microbiology, 5(1): DOI: 10.5580/4f1.



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Ahaotu, C. C., Ogueke, C. I., Owuamanam, N. N., Ahaotu and Nwosu, J. N. (2011). Protein improvement in gari by the use of pure cultures of microorganisms involved in the natural fermentation process. Pakistan Journal of Biological Science, 14: 933-938. Akinfala, E. O and Tewe, O. O. (2004). Supplementatal effects of feed additives on the utilization of whole cassava plant by growing pigs in the tropics. Livestock Research for Rural Development, 16: 10. Akinyosoye, F. A., Adeniran, A. H. and Oboh, G. (2003). Production of fungal amylase from agroindustrial wastes. Peer-reviewed Proceeding of the 16th Annual Conference of Biotechnology Society of Nigeria, 35-40. Akpomie, O. O., Akponah, E. and Okorawhe, P. (2012). Amylase production potentials of bacterial isolates obtained from cassava root peels. Agricultural Science Research Journal, 2(2): 95 – 99. Arotupin, D. J. (2007). Evaluation of microorganisms from cassava wastewater for production of amylase and cellulose. Research Journal of Microbiology, 2(5): 475-480. Arowolo, A. A., Adaja, J. I. (2012). Investigation of Manihot Esculenta and Manihot Duleis Production in Nigeria: An Econometric Approach. Journal of Applied Science and Environment, 3:18-24. Avancini, S. R. P., Faccin, G. L., Vieira, M. A., Rovaris, A. A., Podesta, R., Tramonte, R., de Souza, N. M. A. and Amante, E. R. (2007). Cassava starch fermentation wastewater: characterization and preliminary toxicological studies. Food and Chemical Toxicology, 45: 2273 – 2278. Ayeni, F. A., Sánchez, B., Adeniyi, B. A., de los Reyes-Gavilán, C. G., Abelardo Margolles, A. and Ruas-Madiedo, P. (2011). Evaluation of the functional potential of Weissella and Lactobacillus isolates obtained from Nigerian traditional fermented foods and cow's intestine. International Journal of Food Microbiology, 147: 97–104. Bajaj, I. and Singhal, R. (2011). Poly(glutamic acid) – An emerging biopolymer of commercial interest. Bioresource Technology, 102: 5551–5561. Barana, A. C. (2000). Avalicao de tratamento de manipuiera em biodigestores fase acidogenica e metanogenica. Botucatu: UNESP/FCA (TESE- Doutorado)., p. 95. Battestin, V., Macedo, G. A. and De Freitas, V. A. P. (2008). Hydrolysis of epigallocatechin gallate using a tannase from Paecilomyces variotii. Food Chemistry, 108: 228-233. Belitsky, B. R. (2002). Biosynthesis of amino acids of the glutamate and aspartate families, alanine, and polyamines. In A. L. Sonenshein, J. A. Hoch, and R. Losick (ed.), Bacillus subtilis and its closest relatives: from genes to cells. American Society for Microbiology, Washington, DC. p. 203–231. Belmares, R., Contreras-Esquivel, J. C., Rodríguez-Herrera, R., Coronel, A. R. and Aguilar, C. N. (2004). Microbial production of tannase: an enzyme with potential use in food industry. Lebensmittel-Wissenschaft und -Technologie, 37: 857–864. Beux, M. R., Soccol, C. R., Marin, B., Tonial, T. and Roussos, S. (1995). Cultivation of Lentinus edodes on the mixture of cassava bagasse and sugarcane bagasse. In: Roussos, S., Lonsane, B.K., Raimbault, M. and Viniegra-Gonzalez, G. (eds.) Advances in Solid State Fermentation. Kluwer Academic Publishers, Dordrecht, pp. 499 – 511. Bignell, C. R. and Thomas, C. M. (2001). The bacterial ParA-ParB partitioning proteins. Journal of Biotechnology, 91: 1-34.


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Branda, S. S., Gonza´lez-Pastor, J. E., Dervyn, E., Ehrlich, S. D., Losick, R. and Kolter, R. (2004). Genes involved in formation of structured multicellular communities by Bacillus subtilis. Journal of Bacteriology, 186(12): 3970–3979. Commichau, F. M., Gunka, K., Landmann, J. J. and Stulke, J. (2008). Glutamate metabolism in bacillus subtilis: gene expression and enzyme activities evolved to avoid futile cycles and to allow rapid responses to perturbations of the system. Journal of Bacteriology, 190(10): 3557–3564. Cuzin, N., Ouattara, A. S., Labat, M. and Garcia, J. (2001). Methanobacterium congolense sp. nov., from amethanogenic fermentation of cassava peel. International Journal of Systematic and Evolutionary Microbiology, 51: 489–493. Damasceno, S., Cereda, M.P., Pastore, G.M. and Oliveira, J.G. (2003). Production of volatile compounds by Geotrichum fragrans using cassava wastewater as substrate. Process Biochemistry., 39: 411 – 414. Dymecki S. M. (2000). Site-specific recombination in cells and mice. In: Joyner, A. L. (ed.) Gene targeting: A practical approach. Oxford: Oxford University Press. p 37–100. Elijah, A. I. and Asamudo, N. U. (2015). Molecular Characterization and Potential of Fungal Species Associated with Cassava Waste. British Biotechnology Journal, 10(4): 1-15. Elijah, A. I., Atanda, O. O., Popoola, A. R. and Uzochukwu, S. V. A. (2014). Molecular Characterization and Potential of Bacterial Species Associated with Cassava Waste. Nigerian Food Journal, 32 (2):56 – 65. Herschlag, D. (1995). RNA Chaperones and the RNA Folding Problem. Journal of Biological Chemistry, 270(36): 20871–20874. Hirt, R. P., Muller, S., Embley, T. M. and Coombs, G. H. (2002). The diversity and evolution of thioredoxin reductase: new perspectives. Trends in Parasitology, 18: 302–308. Hou, W., Chen, X., Song, G., Wang, Q. and Chang, C.C. (2007). Effect of copper and cadmium on heavy metal polluted water body restoration by duckweed (Lemna minor). Plant Physiology and Biochemistry, 45: 62–69. Iyayi, E. A and Lossel, D. M. (2000). Protein enrichment of cassava by-products through solid state fermentation by fungi. The Journal of Technology in Africa, 6(40): 116-118. Jiang, C., Li, S-X., Luo, F-F., Jin, K., Wang, Q., Hao, Z-Y., Wua, L-L., Zhao, G-C Maa, GF., Shen, P-H., Tang, X-L. and Wua, B. (2011). Biochemical characterization of two novel β-glucosidase genes by metagenome expression cloning. Bioresource Technology, 102: 3272–3278. Jun, C. S., Yoo, M. J., Lee, W. Y., Kwak, K. C., Bae, M. S., Hwang, W. T., Son, D. H. and Chai, K. Y. (2007). Ester derivatives from tannase-treated prunioside A and their antiinflammatory activities. Bulletin of the Korean Chemical Society, 28: 73-76. Kostinek, M., Specht, I., Edward, V. A., Schillinger, U., Hertel, C., Holzapfel, W. H. and Franz, C. M. A. P. (2005). Diversity and technological properties of predominant lactic acid bacteria from fermented cassava used for the preparation of Gari, a traditional African food. Systematic and Applied Microbiology, 28: 527–540. Lade, H. S., Chitanand, M. P., Gyananath, G. and Kadam, T. A. (2006). Studies on some properties of bacteriocins produced by Lactobacillus species isolated from agro-based waste. The Internet Journal of Microbiology, 2(1). Lekha, P. K. and Lonsane, B. K. (1997). Production and application of tannin acyl hydrolsase: state of the art. Advances in Applied Microbiology, 44: 215–260.



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Liu, Y., Toh, H., Sasaki, H., Zhang, X. and Cheng, X. (2012). An atomic model of Zfp57 recognition of cpg methylation within a specific DNA sequence. Genes and Development, 26: 2374-2379. Longhese, M. P., Plevani, P. and Lucchini, G. (1994). Replication factor A is required in vivo for DNA replication, repair, and recombination. Molecular and Cellular Biology, 14: 7884-7890. Lu, M. J. and Chen, C. (2007). Enzymatic tannase treatment of green tea increases in vitro inhibitory activity against N-nitrosation of dimethylamine. Process Biochemistry, 42: 1285-1290. Lu, M. J. and Chen, C. (2008). Enzymatic modification by tannase increases the antioxidant activity of green tea. Food Research International, 41: 130-137. Nishitani, Y., Sasaki, E., Fujisawa, T. and Osawa, R. (2004). Genotypic analyses of Lactobacilli with a range of tannase activities isolated from human faeces and fermented foods. Systematic and Applied Microbiology, 27: 109–117. Nitschke, M., Pastore, G.M. (2006). Production and properties of a surfactant obtained from Bacillus subtilis grown on cassava wastewater. Biores. Technol., 97: 336 – 341. Obadina, A. O., Oyewole, O. B., Sanni, L. O., and Abiola, S. S. (2006). Fungal enrichment of cassava peels protein. African Journal of Biotechnology, 5 (3): 302-304. Oboh, G. (20060. Nutrient enrichment of cassava peels using a mixed culture of Saccharomyces cerevisiae and Lactobacillus spp. Solid media fermentation. Electronic Journal of Biotechnology, 9(1): 46-49. Ogbo F. C. (2010). Conversion of cassava wastes for biofertilizer production using phosphate solubilizing fungi. Bioresource Technology, 101: 4120–4124. Oghenejoboh, K. M., Otuagoma, S. O. and Ohimor, E. O. (2016). Application of cassava peels activated carbon in the treatment of oil refinery wastewater – a comparative analysis. Journal of Ecological Engineering, 17(2): 52–58. Olowoyo, O. O., Akinyosoye, F. A. and Adetuyi, F. C. (2000). Micro-organisms associated with some cassava (Manihot esculenta, Crantz) products. J. Res. Rev. Sci. 2: 10-14. Osuntogun, B. A., Adewusi, S. R. A., Telek, L. and Oke, O. L. (1987). The effect of tannin content on the nutritive value of some leaf protein concentrates. Human Nutrition: Food Science and Nutrition, 41(F):41-46. Oyeleke, S. B. and Oduwole, A. A. (2009). Production of amylase by bacteria isolated from a cassava waste dumpsite in Minna, Niger State, Nigeria. African Journal of Microbiology Research, 3 (4): 143 – 146. Pandey, J., Ganesan, K. and Jain, R.K. (2007). Variations in T-RFLP profiles with differing chemistries of fluorescent dyes used for labelling the PCR primers. Journal of Microbiological Methods., 68: 633 – 638. Raab, T., Bel-Rhlid, R., Williamson, G., Hansen, C. E. and Chaillot, D. (2007). Enzymatic galloylation of catechins in room temperature ionic liquids. Journal of Molecular Catalysis, 44: 60-65. Ratnadewi, A. A. I., Santosoa, A. B., Erma Sulistyaningsih, E. and Wuryanti Handayania, W. (2016). Application of Cassava Peel and Waste as Raw Materials for Xylooligosaccharide Production using Endoxylanase from Bacillus subtilis of Soil Termite Abdomen. Procedia Chemistry, 18: 31 – 38.


248

Aniekpeno I. Elijah

Raupp, D. d-S., Rosa, D. M., Marques, S. H. d-P. and Banzatto, D. A. (2004). Digestive and functional properties of a partially hydrolyzed cassava solid waste with high insoluble fiber concentration. Scientia Agricola (Piracicaba, Braz.) 61(3): 286 – 291. Riaz, S., Nawaz, S. K. and Hasnain, S. (2010). Bacteriocins produced by Lactobacillus fermentum and Lactobacillus acidophilus can inhibit cephalosporin resistant E. coli. Braziliann Journal of Microbiology, 41: 643-648. Riley, M. A. (2009). Bateriocins, biology, ecology and evolution. Encyclopedia of Microbiology. (Moselio Schaechter, Ed.), Oxford: Elsevier, pp. 32-44. Sackey, I. S. and Bani, R. J. (2007). Survey of waste management practices in cassava processing to gari in selected districts of Ghana. Journal of Food Agriculture and Environment, 5 (2): 325-328. Saha, B. C. (2003). Hemicelluloses bioconversion. Journal of Industrial Microbiology and Biotechnology, 30: 279–291. Sakai, K., Sonoda, C., Murase, K. (2000). Bitterness relieving agent. J. P. patent WO0021390. Salje, J. 2010. Plasmid segregation: how to survive as an extra piece of DNA. Critical Reviews in Biochemistry and Molecular Biology, 45(4): 296–317. Schroeder, R., Barta, A. and Semrad, K. (2004). Strategies for RNA folding and assembly. Nature Reviews Molecular Cell Biology, 5: 908–919. Sonnenberg, A. S. M., Baars, J. J. P., Obodai, M. and Asagbra, A. (2014). Cultivation of oyster mushrooms on cassava waste. Proceedings of the 8th International Conference on Mushroom Biology and Mushroom Products (ICMBMP8), 286 – 291. Srioth, K., Chollakup, R., Chotineeranat, S., Piyachomkwan, K. and Oates, C. G. (2000). Processing of cassava waste for improved biomass utilization. Bioresource Technology, 71(1): 63-69. Tanimoto, H., Fox, T., Eagles, J., Satoh, H., Nozawa, H., Okiyama, A., Morinaga, Y., Susan, J. and Fairweather-Tait, S. J. (2007). Acute effect of poly-glutamic acid on calcium absorption in post-menopausal women. Journal of the American College of Nutrition, 26 (6): 645–649. Tweyongyere, R and Katongole, I. (20020. Cyanogenic potential of cassava peels and their detoxification for utilization as livestock feed. Veterinary and Human Toxicology, 44(6): 366-369. Ubalua, A. O. (2007). Cassava wastes: Treatment options and value addition alternatives. African Journal of Biotechnology, 6 (18): 2065-2073. Ugwuanyi, J.O., Harvey, L.M., McNeil, B. (2007). Linamarase activities in Bacillus spp. Responsible for thermophilic aerobic digestion of agricultural wastes for animal nutrition. Waste Management, 27: 1501-1508. Urbano, G., Lopez-Jurado, M., Porres, J. M., Frejnagel, S., Gomez-Villalva, E., Frias, J., Vidal-Valverde, C. and Aranda, P. (2007). Effect of treatment with α-galactosidase, tannase or a cell-wall-degrading enzyme complex on the nutritive utilization of protein and carbohydrates from pea (Pisum sativum L.) flour. Journal of the Science of Food and Agriculture, 87: 1356-1363. Wang, W., Xie, L., Luo, G. and Lu, Q. (2012). Optimization of biohydrogen and methane recovery within a cassava ethanol wastewater/waste integrated management system. Bioresource Technology, 120: 165 – 172.



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Wirth, J., Chopin, F., Santoni, V., Viennois, G., Tillard, P., Krapp, A., Lejay, L., DanielVedele, F. and Gojon, A. (2007). Regulation of root nitrate uptake at the NRT2.1 protein level in Arabidopsis thaliana. Journal of Biological Chemistry, 282: 23541–23552. Ye, J., Cho, S- H., Fuselier, J., Li, W., Beckwith, J. and Rapoport, T. (2007). A Crystal structure of an unusual thioredoxin protein with a zinc finger domain. Journal of Biological Chemistry, 282(48):34945–34951.

BIOGRAPHICAL SKETCH Aniekpeno Isaac Elijah, PhD Affiliation: Department of Food Science and Technology, University of Uyo, Uyo, Akwa Ibom State, Nigeria Education: Ph.D. Food Microbiology and Biotechnology (2013) - Federal University of Agriculture, Abeokuta, Nigeria M.Sc. Food Processing and Preservation (2004) - Michael Okpara University of Agriculture, Umudike, Nigeria B. Sc. Brewing Science and Technology (2000) - University of Uyo, Nigeria Research and Professional Experience: Senior Lecturer 2013 till date Lecturer I 2010 – 2013 Lecturer II 2007 – 2010 Assistant Lecturer 2005 - 2007 Teaching and supervision of postgraduate and undergraduate students Professional Appointments: (i) Secretary, Nigerian Institute of Food Science and Technology South East Chapter, Nigeria - June 2013 till Feb., 2016 (ii) Co-ordinator, Nigerian Institute of Food Science and Technology, Uyo Zone, NigeriaJune 2013 till date (iii) Secretary LOC, Nigerian Institute of Food Science and Technology, South East Chapter Food Summit - June 2014 Honors: Best Graduating Student, Faculty of Natural and Applied Sciences, University of Uyo – 2000 Publications: 1. Elijah, A.I. and Asamudo, N. U. 2015. Molecular characterization and potential of bacterial species associated with cassava waste. British Biotechnology Journal, 10(4):1-15.


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Aniekpeno I. Elijah 2. Elijah, A.I., Atanda, O.O., Popoola A.R and Uzochukwu, S.V.A. 2015. Diversity and techno-functional properties of bacterial species associated with cassava waste. Proceedings of the 2nd International Conference on Food and Biosystems Engineering, Mykonos Island, Greece, 28th to 31st May 2015. 3. Elijah, A.I., Atanda, O.O., Popoola A.R and Uzochukwu, S.V.A. 2014. Molecular characterization and potential of bacterial species associated with cassava waste. Nigerian Food Journal, 32(2): 57-66. 4. Elijah, A.I., Atanda, O.O., Popoola A.R and Uzochukwu, S.V.A. 2014. Genes of industrial importance on cassava waste bacteria plasmids. Proceedings of the 17th IUFoST World Congress of Food Science and Technology, Montrael, Canada, 17th 21st August, 2014. 5. Umo-udofia, S. J., Edem, V. E. and Elijah, A. I. 2014. Effect of soaking time and storage period on the moisture content of smoked bonga fish (Ethmalosa fimbriata). Book of extended abstract for the 1st NIFST South-East Chapter Food Summit, Uyo, 38 – 40. 6. Umo-udofia, S. J., Edem, V. E. and Elijah, A. I. 2014. Microbilogical quality and sensory attributes of smoked bonga fish (Ethmalosa fimbriata) obtained from Oron, Akwa Ibom State, Book of extended abstract for the 1st NIFST South-East Chapter Food Summit, Uyo, 40 – 43. 7. Ojimelukwe, P., Elijah, A., Ekong, U. and Nwokocha, K. 2013. Effect of different preservatives on the shelf-life of Kunun zaki A traditional fermented cereal based non-alcoholic beverage. Nigerian Journal of Agriculture, Food and Environment, 9(1): 76 – 79. 8. Adamu, L., Edeghagba, B., Abiola, O., Elijah, A. I. and Ezeokoli, O. 2013. Antimicrobial activity of extracts of Jatropha curcas and Calotropis procera leaves against pathogenic isolates from motorcycle helmets in Lagos metropolis. International Journal of Current Microbioliology and Applied Science, 2(12): 292302. 9. Elijah, A. and Ojimelukwe, P. 2013. Use of botanicals in palm wine preservation. Lambert Academic Publishing, Deutsshland, Germany.




Chapter 13

POTENTIAL USES OF CASSAVA PRODUCTS AND ITS FUTURE CHALLENGING OPPORTUNITIES Reddy T. Ranjeth Kumar, Kim Hyun-Joong* and Park Ji-Won 1

Lab. Of Adhesion and Bio-Composites, Program in Environmental Materials Science, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea

ABSTRACT Cassava is the third largest source of food carbohydrates in the tropics after rice and maize. Cassava is a major staple food in the developing world, providing a basic diet for over half a billion people. Cassavas are multipurpose commercial products that have many potential uses, such as in bio-fuels, animal feed, medicines, bio-composite, food packaging and so on. Apart of from these uses, processed cassava serves as an industrial raw material for the production of adhesives, bakery products, dextrin, dextrose, glucose, lactose and sucrose. This chapter elucidates the uses of cassava products and its future challenging opportunities.

Keywords: cassava, products, applications

INTRODUCTION Cassava is the most important cultivated crop in the tropics after rice and corn. Sometimes, cassava is branded as a “third world crop”. It belongs to the family Euphorbiaceae and is referred to as Manihotesculenta Crantz. (Euphorbiaceae) botanically, as shown in Figure 1. The genus Manihot comprises 98 species, of which M. esculenta is the *

Corresponding authors address: Prof. Hyun-Joong Kim. Lab. Of Adhesion & Bio-Composites, Program in Environmental Materials Science, College of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Republic of Korea. Email: [email protected].


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most widely cultivated member [1]. Cassava originated in South America and subsequently has been distributed to tropical and subtropical regions of Africa and Asia. The enlarged tuberous root of the cassava plant contains carbohydrates of a highly nutritional value, with only rice and sugar cane having more carbohydrates [2]. The derived products from cassava are the staple food for more than 1 billion people due to the high starch content. By the 192030s, cassava had attained its present status as one of the major African staple food crops, and currently, the total annual production of approximately 85 million tons is greater than that of any other crop in Africa. At the end of the 20th century, cassava had a vital role in the economic life of sub-Saharan Africa, both as a reliable food source for rural and urban populations and as an important source of income through the sale of fresh and processed produce. It was estimated that, on average, each African eats nearly 80 kg of cassava annually. Due to many superior properties and potential nutritional value, cassava has been the focus of research and development and has been identified as a good commodity source for the wider growth of the economy [3-4]. The cassava plant can be continuously harvested, growing and yielding well under conditions of marginal soil and low acidic rainfall. Moreover, this is an attractive energy crop due to its high carbohydrate content, superior starch conversion for ethanol, high water-use efficiency, and high rate of CO2 fixation. All of these characteristics make it a commonly grown, low-cost crop that is well suited for small-scale biofuel feedstock production. Cassava has been used for bioethanol production in Brazil and Asia for several years, and several studies have investigated this potential in sub-Saharan Africa [5]. Cassava is categorized into two types: sweet and bitter. Due to deterioration by pests, animals, and thieves, most cultivators prefer the bitter type of cassava. The roots and tubers of both the sweet and bitter varieties contain toxins and anti-nutritional factors. Before consumption of cassava, it must be prepared properly. Often, improper preparation of cassava can leave enough residual cyanide to cause acute cyanide intoxication and goiters and may even cause ataxia or partial paralysis. The more toxic varieties of cassava are a fallback resource (a “food security crop”) in times of famine in some places [6]. According to United States Department of Agriculture, Agricultural Research Service, National Nutrient Database for Standard Reference Release 28 basic report 11134, the nutritional content of raw cassava is listed in Table 1 [7].

Figure 1. Cassava plant [6].


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Table 1. Nutrient information of raw cassava Nutrient Proximate Water Energy Protein Total lipid (fat) Carbohydrate, by difference Fiber, total dietary Sugars, total Minerals Calcium, Ca Iron, Fe Magnesium, Mg Phosphorus, P Potassium, K Sodium, Na Zinc, Zn Copper, Cu Manganese, Mn Selenium, Se Vitamins Vitamin C, total ascorbic acid Thiamin Riboflavin Niacin Vitamin B-6 Folate, total Vitamin A, IU Vitamin E (alpha-tocopherol) Vitamin K (phylloquinone)

Unit

Value per 100 g

g kcal g g g g g

59.68 160 1.36 0.28 38.06 1.8 1.7

mg mg mg mg mg mg mg mg mg µg

16 0.27 21 27 271 14 0.34 0.1 0.384 0.7

mg mg mg mg mg µg IU mg µg

20.6 0.087 0.048 0.854 0.088 27 13 0.19 1.9

BIO-COMPOSITES WITH CASSAVA There is lot of interest in replacing nondegrable materials with degradable materials in many areas. Most studies have focused on biopolymers, such as natural biopolymers, synthetic biodegradable polymers and biopolymers that are formed by microbial fermentation and are used for making biodegradable composites, and among those biopolymers, natural biopolymers, such as starch, show good promise for making biodegradable composites. Starch is a promising candidate due to its many superior properties, such as its low cost, renewable, recyclable, biodegradable, thermoplastic behavior and abundant availability. Conversely, there are also some drawbacks to the use of starches, such as high water solubility, poor melting processability, and difficulty in processing and brittleness, which necessitates the use of a plasticizer to make them suitable for engineering applications. Starch


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can be processed into thermoplastic starch by breaking its structure under high temperature and shear stress; this causes intermolecular rearrangement due to de-structuring of the starch chains. In this de-structuring of the starch chains, plasticizers, such as glycerin, play a vital role. Furthermore, the properties of this thermoplastic starch can change depending on the concentration of plasticizer used. For example, the cassava starch glass transition temperature (Tg) is reported to be 131.9°C, and this temperature decreases with the addition of glycerol. At 30% glycerol content, the value of Tg is 62.2°C. The tensile properties are also reported to change accordingly [8]. Moreover, the mechanical properties of starch could be improved by using reinforcement with natural fibers, such as from kenaf, jute, sugarcane fiber, flax, sisal, bagasse and other cellulose fibers. Composites with this reinforcement of fibers are referred to as “biocomposites” or “green composites”. These composites should be considered eco-friendly composites because of their superior biodegradability and compostability without any damage to the environment. Additionally, natural fibers are not only used to enhance the properties of biopolymers but have other advantages as well, such as their abundant availability, renewability and low cost. The enhancement of properties was observed in the preparation of bio-composites with cassava starch and green coconut fiber. In this study, composites were prepared using a compression molding process, and their characterization regarding their tensile properties and water absorption properties were analyzed before and after thermal treatment of the matrix and composites. The tensile strength and Young’s modulus of the composites containing 30% of coir fibers in a thermoplastic starch matrix was shown to be enhanced by 212.2% and 366.7%, respectively, for treated thermoplastic starch composites compared with untreated thermoplastic starch composites. Conversely, the water uptake, moisture absorption and swelling properties of thermoplastic starch decreased with an increase in the coir fiber content [9]. Souza et al. observed the influence of glycerol and clay nanoparticles on the tensile, barrier and glass transition temperatures of cassava starch biodegradable films. The incorporation of a lower content of glycerol and sugar-derived plasticizers were compatible with the starch to enhance the tensile and barrier properties compared with a higher content these additives. In addition, the tensile and barrier properties were significantly influenced by adding both glycerol and clay nanoparticles, whereas the permeability was greatly decreased when clay nanoparticles were present, and the glass transition temperature did not change [10]. Matsui et al., analyzed cassava bagasse-kraft paper composites with the addition of starch acetate. Cassava bagasse, which is extracted from the industrial production of cassava starch and used to obtain a cardboard composite, is used in small-scale artisan production of recycled paper. A mixture of 90% cassava bagasse and 10% kraft paper was used for the production of these composites. However, the addition of kraft fiber to cassava bagasse improves the properties of the material. These materials have similar characteristics to the molded fiber packaging made using recycled paper, such as the material used in egg boxes. The prepared composites were immersed in water to study the water absorption properties, and the composites showed slight resistance to direct water contact. The effect of starch acetate on the absorption of water mass was approximately half that of the materials without impregnation. However, the impregnation had little influence on the tensile strength of the tested samples. Starch acetate is, therefore, an attractive additive for use in the manufacture of waterproof materials, such as disposable trays [11].



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Additionally, the effect of chitosan was observed on montmorillonite (MMT) that was incorporated into cassava starch composite films. Chitosan acts as a compatibilizing agent to maintain the homogeneous dispersion of clay particles in a starch matrix. Due to hydrophilicity, chitosan plays a significant role between the starch matrix and montmorillonite. As a result, a low MMT content in cassava starch improves the tensile properties of composite films. Moreover, an increase in the chitosan content of the composite films increases the surface hydrophobicity and water vapor transmission and decreases moisture absorption [12]. Farias et al. prepared and characterized blended composites with cassava bagasse and low-density polyethylene (LDPE). The incorporation of cassava bagasse in the LDPE demonstrated a positive result with an enhancement of the elastic modulus value from 131.90 to 186.2 MPa, with up to a 30% reinforcement of cassava bagasse with LDPE [13]. A similar effect was observed in the preparation and characterization of cassava fiber reinforced with polypropylene (PP) and polybutylene succinate (PBS) composites. Maleic anhydridepolypropylene (MAPP) was used as a compatibilizer to improve the interfacial strength between the fibers and matrix. An increase in the fiber content of the composites increased the Young’s modulus and flexural strength in both the PP and PBS matrix-reinforced composites to levels that were nearly 50% greater than the pure matrix composites. From this result, fiber reinforced composites show a better stiffness compared with pure composites. Conversely, the tensile strength and flexural strength decreased with an increase in the fiber content. Moreover, the thermal stability of the composites increased with the presence of MAPP in both PP and PBS composites. This result suggests the enhancement of the interfacial interaction and compatibility due to the treatment with the compatibilizer [14]. Modified Eucalyptus pulp cellulose fibers with a deposition of silica (SiO2) nanoparticles were used in cassava starch bio-composites. The modified and unmodified pulp fibers composites were prepared with 5% and 10% nanoparticles by weight, and the tensile strength and moisture adsorption were analyzed. The addition of modified fibers improved the tensile strength by 183% compared with that of the thermoplastic starch (TPS) composites, whereas the moisture adsorption decreased by 8.3%. These properties of unmodified fibers were greater than of the modified fiber composites because of the poor interaction between the modified fiber and matrix [15]. Moraes et al. introduced a tape-casting technique for the formation of cassava starch-based films. Generally, the extrusion process for the preparation of cassava starch films will not result in good properties due to the greater shear rates applied. Instead of this extrusion process, the tape-casting technique improves the shear rate by having an adjustable blade at the bottom of the spreading device. The films were prepared with varying concentrations of starch, glycerol and cellulose fibers. Moreover, the results have shown a satisfactory viscosity with a low shearing rate. These flow properties and interactions at the liquid–solid interface have shown that suspensions with fibers are suitable to be processed using the tape-casting technique [16]. Some other researchers used cassava root peel and bagasse as natural fillers in the preparation of bio-composites. The mechanical and optical properties of these composites were studied. The addition of filler resulted in a significant change in the properties of the composites. The filler addition increased the UVbarrier capacity and the opacity of the composite materials. Peel and bagasse fillers were added to the TPS in the range of 0.5to1.5%. The peel-reinforced composites had a greater tensile strength with a 0.5% addition of TPS, whereas bagasse addition (1.5%) increased the elastic modulus by 260% and the maximum tensile stress of the TPS composites by 128%,


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which makes it the most efficient reinforcing agent due to its high residual starch content and lower proportion of smaller particles [17]. Moreover, compression molding has been used for the preparation of pregelatinized cassava starch/kaolin composites. The composites obtained have been studied with respect to their structure and properties. The mechanical and thermal properties were observed to be better than those of TPS. The tensile strength of the composites was greater with a 10 wt% kaolin content but decreased with additional kaolin content; however, the tensile strength was still greater than that of TPS. Similarly, the thermal degradation temperature was greater with 60 wt.% kaolin added to the TPS. This improvement in thermal stability by the addition of kaolin was because kaolin acts as a heat barrier [18].

WHAT IS BIO-FUEL ? Bio-fuels from renewable resources have recently gained significance as an alternative to finite fossil fuels and a potential solution to ending our dependence on declining natural resources. Bio-fuels are most often used as a motor fuel and are mainly used an additive for gasoline. Bio-fuels are a domestically produced alternative fuel and are made from corn; cellulosic feedstocks, such as crop residues and wood; or can be made from any crop or plant that contains natural sugar (beet and cane). Crops, such as corn, wheat and barley, contain starch that can be easily converted in to sugar, and most trees and grasses are made of cellulose, which can also be converted into sugar. The renewable fuel standard (RFS2) as part of the Energy Independence and Security Act of 2007 (EISA) requires the annual U.S. consumption of biofuels to be 36 billion gallons by the year 2022. Of this amount, 15 billion gallons are to be conventional biofuels most likely achieved using ethanol from corn. The remaining 21 billion gallons are to be advanced biofuels from feedstocks other than corn, 16 billion gallons of which are to be cellulosic biofuels derived from cellulose, hemicellulose, or lignin. Feedstocks for these advanced biofuels include plant residues (e.g., corn stover, cereal grain straw, and forestry residues), dedicated energy crops (e.g., switchgrass, energy cane, and hybrid poplar), and other sources of biomass (e.g., municipal solid waste and algae). Another 1 billion gallons of advanced biofuels are to be biomass-based diesel, which is primarily biodiesel from soybean oil, other vegetable oils, and animal fats. Meeting RFS2 targets would increase the share of renewable fuel by volume to approximately one-quarter of the U.S. gasoline by 2022 [19]. Ethanol, which is also called ethyl alcohol, is produced by a fermenting and distilling biomass. Most significantly, ethanol can be used as a bio-fuel or fuel additive from renewable energy resources. It is the base of most of alcoholic beverages and is used in many pharmaceutical and beauty products. The significance of ethanol is reduced deforestation, free of air pollutant, contains a greater octane rating than petrol as a fuel, is an excellent raw material for synthetic chemicals, improves economic development in rural areas, provides more jobs, increases revenue from producing countries, and reduces adverse foreign trade balances. The general processing of ethanol is a four-step process:



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1. Feedstocks (crop or plant) are ground up for easier processing; 2. Sugar is dissolved from the ground material or the starch or cellulose is converted to sugar; 3. Microbes feed on the sugar producing ethanol and carbon dioxide as by products; and 4. Ethanol is purified to achieve the correct concentration.

ETHANOL PRODUCTION BY CASSAVA Cassava has great potential as a raw material for ethanol production because it contains a large amount of starch and cellulosic substances that can be hydrolyzed and fermented to make ethanol. The production of ethanol using cassava follows a five-step process: Grinding; 1. Liquefaction; 2. Saccharification; 3. Fermentation; and 4. Distillation.

Figure 2. Ethanol production process using cassava.


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1. Grinding and Liquefaction First, the collected cassava roots and other materials are milled into flour. Generally, in the industry, this is referred to as “meal” and is processed without separating out various component parts of the grain. To form a “mash” of the product, the meal is slurried with water at 90∼95°C. 2. Saccharification Enzymes are added to the mash to convert starch to dextrose and sugar. Ammonia is added for pH control and as a nutrient for yeast. The mash is processed in a high-temperature cooker to reduce bacterial levels prior to fermentation. 3. Fermentation After the saccharification process, the mash is cooled and transferred to fermenters where yeast is added. The yeast Saccharomyces cerevisiae is activated. Due to this microbial activity, the conversion of sugar to ethanol and carbon dioxide (CO2) begins. 4. Distillation Finally, water is evaporated in the distillation process, which increases the purity of ethanol. Kosugi et al. produced ethanol from cassava pulp via fermentation with a surface engineered yeast strain displaying glucoamylase. The significance of this process is that without the addition of amylolytic enzymes, Saccharomyces cerevisiae Kyokai no. 7 (strain K7) fermented both the starch and glucose in pretreated samples and produced ethanol at 91% and 80% of the theoretical yield from 5% and 10% cassava pulp, respectively [20]. Klanarong et al. reported that good cultivation practices are important to improve the yield of cassava roots and significantly increased the yield from 22 to 60 tons/hectare (ha). The process of cultivation is composed of many aspects, including soil plowing, high stake quality, weed control, good planting and harvesting period, land conservation with organic fertilizers and water irrigation. Globally, the production of cassava is approximately 200 million tons per annum, with an average yield of 12 tons/ha and a total acreage of 18.5 million ha. This report suggests that if cassava root productivity increases, for example, by 5 tons/ha, approximately 90 million tons of roots will be produced, which can be converted to 15,000 ML of ethanol using the simultaneous saccharification and fermentation (SSF) process, which is a current production process in which cooked and enzymatically liquefied cassava materials are subjected to saccharification enzymes and yeasts in concert. Instead, an uncooked process of a granular starch-hydrolyzing enzyme has been introduced to improve the ethanol production efficiency [21]. The energy efficiency of cassava fuel ethanol was estimated by China, and the net energy value [NEV] and net renewable energy value [NREV] were indicated to be 7.475 MJ/L and 7.881 MJ/L, respectively. The solar energy trapped is greater than the energy used in the processes. Moreover, the ethanol fuel produced from cassava can be used for transportation. Through fuel ethanol production, cassava can produce 9.8 J of fuel ethanol by consuming an input of 1 J of petroleum fuel and other forms of energy inputs, such as coal. Nevertheless, this cassava fuel ethanol can be an alternative for gasoline and other reduced oil imports because, based on the estimation of the cassava output in 2003, this fuel ethanol can substitute for 166.107 million liters of gasoline. This potential cassava output can replace 618.162 million liters of gasoline. These results indicate that the energy efficiency of cassava fuel is greater than those of gasoline, diesel and corn fuel ethanol products, but less than that



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of biodiesel [22]. Elias et al. produced bio-ethanol by utilizing cellulosic cassava waste. Generally, the chemical composition in cellulosic cassava waste was determined to consist of protein, fiber, insoluble carbohydrates and residual starch content. After the SSF process, dilute HCl was more helpful in converting the cellulosic materials into reducing sugars. Finally, the results showed the obtained fuel ethanol from cassava cellulosic waste to be 2.7 g ethanol/15 g of cellulosic waste, which is equal to 32.4% alcohol [23]. Wei et al. studied the influence of the genotype, growth type and harvest time on cassava stem starch contents and the yield of ethanol production. The design of the experiment contained 3 varieties, 3 locations and 5 harvest times in Guangxi, China. While comparing the cassava stem starch with the root starch, the stem starch content was significantly affected by all parameters, and the location greatly affected the stem starch content compared with variety and harvest timing, whereas root starch was only affected by the location. Additionally, the soil properties were significantly correlated with the starch and sugar contents in both the stem starch and root starch. This promising result showed that stem starch can be used without reducing root starch and can result in approximately 26% ethanol production [24].

Figure 3. Accumulations of (■) lactic acid and (○) acetic acid and (▲) the final alcohol degree during 87 repeated batches [30].

Marco et al. applied genetic algorithms (GAs) to study of the economic viability of alcohol production from cassava root from 2002 to 2013. This GA suggested the hydrolysis occurred for starch concentrations from 8.0 to 22 g/L at temperatures ranging from 30 to 60°C. After the SSF, a significant effect was observed in the production of ethanol and was 88% under the best conditions for starch hydrolysis at 23.4 g/L and 61.9°C and for 111.0 min. The cost of alcohol as determined by the GA was between 0.04 and 0.62 US $/L, and the alcohol sale price were between 0.10 and 0.88 US $/L during this complete study. Furthermore, this method demonstrated that the method is environmental friendly because the implemented (GA) company will acquire 7.8 billion carbon credits, which are equal to 72.477


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US $/year. These results show improvements in bioethanol production in industries through the use of GA [25]. Conversely, Papong et al. analyzed the life-cycle energy and environmental cost of bioethanol production from cassava in Thailand. In this analysis, for 1 L of 99.5% cassavabased bioethanol production, the energy and material inputs and water, air and solid-waste emissions were estimated. A major portion of energy consumption takes place at the stage of ethanol production, which requires 78% of the total energy of usage. Therefore, steam and coal were used for power in this process. This results in a major environmental impact compared with the remaining stages. The results of the net energy gain (NEG) and net energy ratio (NER) values for cassava-based ethanol were found to be -3.72 MJ/L and 0.85, respectively. To increase the NEG and decrease the environmental impact, the alternative solution to coal could be the use of biogas recovered from wastewater treatment [26]. To create a negative energy balance, Ramasamy et al. studied ethanol production from cassava starch using co-immobilized cells. To achieve the fermentation of liquefied starch, these researcher used Saccharomyces diastaticus and Zymomonas mobilis co-immobilized cells. They observed that the co-immobilized cells produced high concentrations of ethanol compared with immobilized cells of S. diastaticus during the batch fermentation of liquefied cassava starch. The immobilized cells of S. diastaticus + yeast could produce 37.5 g/l ethanol from 150 g/l of liquefied cassava starch, but the significant improvement that was demonstrated in the co-immobilized cells produced 46.7 g/1 ethanol. This indicates the mixed culture fermentation results in a greater concentration of ethanol compared with free cells. The ethanol concentration was increased to 53.5 g/l in the repeated batch fermentation using co-immobilized cells [27]. A similar study conducted by Shanavas et al. reported novel ecofriendly enzymes that were used to optimize bioethanol production from cassava starch. In this process, Spezyme and Stargen enzymes were introduced in the SSF process. Spezyme was active even at 90°C, and 10% (w/v) of starch was hydrolyzed at levels of 20.0 mg (280 amylase activity units) at a pH 5.5 for 30 min. Stargen was active at room temperature (30 ± 1 0C) and hydrolyzed the 10% (w/v) of the starch of 100 mg (45.6 granular starch hydrolyzing units). The greatest yield of ethanol was obtained by Spezyme using rapid Saccharification fermentation using Stargen plus a yeast system. The fermentation efficiency for 1 kg of starch was shown to be approximately 98.4%. The specific advantage of the new process was that the reaction could be completed within 48.5 h at 30 ± 1°C) [28]. In the process of achieving bioethanol fuel production, the cost of the feedstock, energy and enzymes used in pretreatment prior to fermentation will dominate. To increase the economic viability and decrease the complexity, non-conventional feedstocks have been proposed as alternatives. These feedstock bioconversion deployments downsize the cost. Cassava starch has been proposed to be a non-conventional feedstock for bioethanol production. The co-culture and monoculture of both Aspergillus sp. and Saccharomyces cerevisiae have been proposed for bioethanol production. The production of bioethanol in co-culture is greater than monoculture production. The efficiency of ethanol is approximately 91-95%. This process efficiently reduces the energy expense [29]. Moreover, the chemical modification of the fibrous matrix was used along with SSF with immobilized Saccharomyces cerevisiae 1308. Without filtration, cassava hydrolysate was used for ethanol fermentation. After seven repeated SSF processes, the utilization of starch obtained by the immobilized cells was approximately 83.5%. The utilization of starch by immobilized cells was 2.1% greater than that of free cells, with an inoculation quantity of 15% (v/v) under the same fermentation conditions. The



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enzyme feeding strategy suggests that the utilization of starch is 85.9% at 35°C. After 6 months and approximately 87 batches of SSF, ethanol production from cassava using immobilized yeast in a fibrous-bed bioreactor is suggested to be feasible and may meet the demands of industrial production, as shown in Figure 3 [30].

CASSAVA IN MEDICINE Starch is a biodegradable polymer and is a promising carrier for drug delivery. Starch has been used in various fields, biomedical, agriculture among others. However, many drugs are released quickly due to the considerable swelling and quick enzymatic degradation of unmodified native starch from biological systems. The chemical modification of starch includes the esterification of native starch, which is referred to as acetylated starch, and this process improves the properties of the starch. The chemical modification of starch into starch acetates will improve the hydrophobicity and decrease the hydrophilicity. In drug delivery applications, this modified starch acetate has been extensively used. Raj et al. investigated cassava starch acetate (CSA)–polyethylene glycol (PEG)–gelatin (G) nanocomposites as a novel controlled drug delivery system for anticancer drugs. These nanocomposites were used to entrap cisplatin (CDDP). In this investigation, the authors prepared CSA-CDDP, CSACDDP-PEG and CSA-CDDP-PEG-G nanocomposites. Then, 0.1 mg of a 10%, 20%, 30%, 40%, or 50% drug loaded sample was suspended in a definite volume (10 ml) of phosphate buffer saline (PBS) at various pH values at 37°C. The resulting suspension was placed in an incubated shaker at 120 rpm for a definite time period (1 h), and five-milliliter aliquots were taken out of the dissolution medium at appropriate time intervals (30 min) and were replaced by the same volume of fresh PBS buffer to maintain the volume of the release medium constant. The amount of drug released was observed using a UV spectrophotometer at 290 nm. The results suggested that the CDDP releasing environment in an acidic medium is faster than in a basic medium from CSA, CSA–PEG and CSA–PEG–G nanocomposites. This is because the binding action plays a vital role by attacking the H+ or Cl- between the drug and carboxyl group in cassava starch acetate nanocomposites. In the body’s environment, the Clconcentration is very high (95∼105 mM) and relatively stable in circulation, and a more acidic environment means more H+, which can speed up the release of CDDP from coated polymeric nanocomposites [31]. Simi et al. prepared hydrophobic grafted and cross-linked cassava starch nanoparticles for drug delivery applications. Indomethacin was used as a model drug and was loaded in cassava starch nanoparticles. Suitable amounts of cassava starch nanoparticle and indomethacin were dissolved in DMSO. In in vitro drug release studies, a dialysis membrane with a molecular weight of 12,000 g/mol was used and a small quantity of the drug-loaded starch nanoparticles were stirred with phosphate buffer at a pH 7.4 at room temperature. At regular intervals, a certain amount of medium was replaced with fresh phosphate buffer. The amount of indomethacin released was determined using a UVvisible spectrophotometer at 320 nm. The greatest amount of drug loading in nanoparticles was identified to be 16%. The controlled drug release was studied at pH 7.4. The surface cross-linking of the starch nanoparticles slowed drug release from the nanoparticle. This significant slowing of drug release in a buffer at pH 7.4 demonstrated that the starch nanoparticle can be used as a good carrier for drugs [32].


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Rajan et al. observed the enzymatic modification of cassava starch using bacterial lipase. For this enzymatic modification of cassava starch, Burkholderia cepacia (lipase PS) of an industrial lipase was used with two acyl donors, lauric acid and palmitic acid. The degree of substitution (DS) of the reactions performed using palmitic acid in a liquid state and using microwave esterification resulted in 62.08% (DS 1.45) and 42.06% (DS 0.98), respectively. The estimation of the α-amylase starch digestibility of the unmodified starch was 76.5%, which was reduced to 18% through modification (DS 1.45). These significant changes in the α-amylase digestion due to the hydrophobicity of the starch esters, in turn, reduce the swelling power. This is suitable for biomedical applications, carriers for controlled release of drugs and bioactive agents. Therefore, enzymatic esterification is ecofriendly [33]. Moreover, for the efficient drug delivery of curcumin (CUR), cassava starch crosslinked with N, Nmethylenebisacrylamide (MBA) microspheres were used. This drug release effect was studied in treating tumor cell lines. For colon cancer treatment, the microspheres were shown to be a capable device for the controlled release of CUR, which, in general, decreases the pH of the colon. The CUR-loaded microspheres presented a much greater activity against Caco-2 and HCT-116 tumor cell lines than free CUR [34].

CASSAVA IN FOOD PACKAGING Souza et al. prepared cassava starch composite films by incorporating cinnamon essential oil and evaluated the antibacterial activity, microstructure, and mechanical and barrier properties. It is necessary to maintain the quality and shelf life of food products through the use of active packaging films. The effect of an increase in the cinnamon essential oil, glycerol and emulsifier contents in the composites films decreased the tensile strength (TS) and elongation at break (E), and these values varied from 2.32 ± 0.40 to 1.05± 0.16 MPa and from 264.03 ± 35.06 to 191.27 ± 22.62%, respectively, indicating a loss of macromolecular mobility. The barrier properties of the composite films increased with an increase in the amount of essential oil incorporated. The water vapor permeability (WVP) and oxygen permeability coefficient (OPC) of the films with cinnamon essential oil varied from 9.78±1.40 to 14.79±2.76 g mm m-2d-1kPa-1and from 27.50 ± 0.60 to 143.47 ± 8.30 ×109 cm3m-1d-1Pa-1, respectively. Furthermore, all films, which contained different amounts of essential oils, showed effective antimicrobial activity against P. commune and E. amstelodami, which are fungi that are commonly found in bread products [35]. It was observed that the effect of kaolinite on cassava starch composites films influences its glass transition temperature (Tg), transparency, UV-vis blocking, water uptake, and decomposition temperatures. As the clay content increased up to 10%, the Tg of the composites decreased. This clay content acted as a plasticizer by reducing the interactions between the polymer chains, which promotes their mobility. Furthermore, the clay content had a barrier effect on water uptake at a low relative humidity, but at a greater relative humidity, the composite films increased their water uptake. Moreover, perfect UV-vis blocking was evident at kaolinite loads between 2% and 6%. These properties of the composite films work effectively for food packaging [36]. Zainuddin et al. prepared and characterized cassava starch bio-composites reinforced with cellulose nanocrystals (CNC) from kenaf fibers. An increase in the CNC content in the thermoplastic starch (TPS) of up to a reinforcement of 6% caused the tensile



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strength and modulus to increase. The thermal stability of the CNC composites reinforced with TPS varied from 280 to 385°C.Whereas, for pure cassava starch, the thermal stability ranged from 273 to 335°C. The thermal stability was attributed to the pyrolysis of the starch yielding products, such as carbon monoxide, volatile organic compounds, and carbonaceous residues. Moreover, water uptake was significantly decreased by the CNC composites reinforced with TPS compared to TPS. These composites were useful for food packaging applications [37]. An edible film was made of agar (AG), cassava starch (CAS), normal rice starch (NRS), and waxy (glutinous) rice starch (WRS) and was tested for the application of edible packaging. The water vapor permeability (WVP) of the films depends on the water vapor pressure gradient and achieves a constant value at RH values greater than 84%. Among these films, AG-based films have a better moisture sorption property compared with CAS films at the same RH conditions. These films had high WVP and hygroscopicity, which restricted their potential use as moisture barrier packaging. Moreover, some foods will retard the water loss during short-term storage. The composed films could be used in the same way. Conversely, all of the films had good mechanical properties except for the WRS-based film. The tensile strength of the NRS, CAS and AG films varied from 28 MPa to 42 MPa and was 8.5 MPa for the WRS film. Specifically, the AG- and CAS-based films plasticized with glycerin were clear, homogeneous, transparent, flexible and easy to handle. Such films are useful for the integrity of the products and the functional properties of the films themselves [38]. The cyanogenesis (SRRC) downstream processing approach was used to reduce cassava-borne environmental waste and to develop peeled (BP) and intact (BI) bitter cassava as biopolymer derivatives. Using the SRRC, the BI approach resulted in a greater yield reduction of approximately 16% waste with no environmental impact caused by the discarded residues. The reduction of the cyanogen content of the cassava gave promising results for industrial applications. The casting method was applied to produce transparent films from both BP and BI derivatives. BI films were more transparent and homogeneous, less soluble, less permeable to moisture, less hydrophilic, more permeable to oxygen and carbon dioxide, sealable, and had a lower cost than the BP films [39]. Bangyekan et al. analyzed the changes in the properties of chitosan-coated cassava starch films. The tensile and barrier properties of the composite films changed significantly with an increase in the concentration of chitosan in the coating. A shift in the starch diffraction peak was likely due to a change in its chain orientation caused by a hydrogen-bonding interaction between the chitosan and starch molecules resulting in good adhesion. The tensile and barrier properties of the composite films increased when increasing the concentration of chitosan [40]. Souza et al. added antioxidant additives from mango and acerola pulps [41] and yerba mate extract [42] into cassava starch bio-based films. These films were investigated for their feasibility of incorporation in a biodegradable matrix. In addition, these films were used to pack palm oil (maintained for 45 and 90 days) under accelerated oxidation conditions (63% relative humidity and 30°C) to simulate a storage experiment. These additives significantly improved the shelf life with a decreasing oxidation effect. The antioxidant activity was obtained due to the presence of phenolic and flavonoid compounds. These results suggest that the incorporation of antioxidant additives into starch-based films will improve the quality of food by degrading the antioxidant action. Furthermore, due to the many superior properties of cassava starch, researchers identified the use of acetylated starch nanoparticles (NPAac) as reinforcements in TPS films. These TPS films were prepared by selecting different portions


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of NPAac, and the mechanical, thermal and barrier properties of the obtained films were studied for food packaging applications. The results of these films reveal a significant improvement in the addition of NPAac as a reinforcement. The Young’s modulus and thermal stability increased by 162% and 15%, respectively, with the addition of 0.5% (w/w) NPAac. Similarly, the WVP was lowered by 41% for the film with 1.5% (w/w) NPAac. These results indicate the reinforcement with NPAac shows significant improvement compared with TPS [43]. To utilize every part of the cassava, Versino et al. used the remaining fibrous residue from cassava starch extraction as a reinforcement for fully biodegradable starch-based composite films. However, the reinforcement of the TPS filler significantly increases the apparent viscosity and storage modulus without segregation of the filler particles. The films were formed using various filler ratios from 0 to 3% (w/w) along with glycerol. The homogeneous films were obtained for all TPS composites films. Reinforced films exhibited a UV-barrier capacity and adequate water vapor barrier properties (14.6 ± 0.7 10−11 g/m s Pa) and tensile strengths (18.01 ± 0.19 MPa) when 25% (w/w) glycerol was added as a plasticizer. The addition of the filler to the TPS increases the mechanical resistance, and furthermore, the obtained eco-compatible materials could be heat-sealed, which indicates their suitability for packaging development [44]. In addition, the edible cassava starch and soy protein concentrate coatings were proven to extend the shelf life of toasted groundnut. The combination of cassava starch and soy protein concentrate with 20% glycerol was applied to toasted groundnut by dip coating. The chemical indices, oxidative rancidity, and sensory parameters were evaluated using standard procedures. The thiobarbituric acid, peroxide and moisture uptake values were greater than 100% cassava starch-coated groundnuts, whereas the blended coated toasted groundnut had lower values. Moreover, the blended film resulted in greater color, texture, taste and overall acceptability scores compared with the 100% cassava starch and control. These combinations of edible coatings extended the shelf life of toasted groundnuts that were stored in ambient (27 ± 1oC) conditions for 14 days compared with uncoated toasted groundnuts [45]. The extension of the shelf life also depends on protection from microbial contaminations, and control is achieved using active packaging films. Franciele et al. prepared active packaging films by incorporating oregano essential oil (OEO) with cassava starch-chitosan blended films. The physicochemical and antimicrobial properties of the obtained films were evaluated. The disc inhibition zone method was applied against Bacillus cereus, Escherichia coli, Salmonella enteritidis, and Staphylococcus aureus. The tensile strength (21.95 ± 1.98 to 1.43 ± 0.26 MPa), elongation at break (%) (21.95 ± 1.98 to 48.4 ± 5.32), Young’s modulus (140.36 ± 5.3 to 18.9 ± 2.61 MPa) and WVP (1.39 ± 1.56 to 0.62 ± 0.15 10−11 g/m s Pa) varied with an increase in the concentration of the OEO from 0∼1% in the cassava starchchitosan blended films. The mechanical properties and WVP decreased compared with the control film. The WVP values decreased with the incorporation of the OEO when increasing its concentration. Correspondingly, the incorporated OEO films demonstrated an effective inhibition against all tested microorganisms, as shown in Figure 4 [46].



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Figure 4. Inhibition zones for (a) cassava starch film, (b) cassava starch-chitosan film, and (c-f) cassava starch-chitosan films with 1% OEO incorporated against the microorganisms (c) S. enteritidis, (d) E. coli, (e) B. cereus, and (f) S. aureus. (Because in a and b no inhibition zones were observed, only one representative plate for each case is shown.) [46]

FUTURE CHALLENGING OPPORTUNITIES FOR CASSAVA There are many potential industrial uses for cassava, such as the development of cassava beers and as a substitute for wheat flour in many countries; for example, Nigeria is likely to save nearly N163 billion annually and create approximately 3 million jobs by using 20% cassava flour blended in wheat flour. Still, many countries have not explored large-scale commercial applications due to the reduced shelf life of cassava roots. It is important to reduce the time gap between production and marketing because most cassava is wasted in this period. The identification of new seed varieties is important to reduce disease to achieve an adequate improvement in yield. Extensive research into breeding is needed to improve the post-harvest storability in the fields as soon as possible. There is a need to find molecular markers for the progeny from crosses. Progeny identification gives the root characteristics while improving the agronomic characteristics and incorporating virus resistance as well as increasing the yield in cold climates. Expanded research on mechanically harvesting cassava is needed. Extensive information is necessary to educate farmers about soil conditions, fertilizers and so on to produce a greater cassava crop yield. The exchange of knowledge is important with respect to processing cassava from different countries and their marketing activities. The global production of ethanol by cassava is still low, and the benefits of cassava need to be explored by using various media and other communications.


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The reduction of the moisture content of cassava products is important to enhance the shelf life of products after a short period of processing. The elimination of toxic glycosides in cassava chips is required before use as a commercial feed for animals. Transgenic programs for cassava are needed to meet the exciting challenge with respect to product development and a quick delivery process [47].

CONCLUSION We conclude that, the cassava is a being multipurpose commercial products having a many potential uses like bio-fuel, animal feed, medicinal, bio-composite, and food packaging use etc. Moreover, this cassava product has significant usage in food industry and a major staple food in the developing world, providing a basic diet for over half a billion people. In the production of ethanol, it is possible to produce 95% of pure ethanol by conversion. The preparation of bio-composites using cassava starch has shown good mechanical and barrier properties for the application of food packaging. The remarkable note identified in drug releasing effect with using cassava starch as a crosslinking agent. Still there is need to identification for increase shelf life of cassava, due to this it is unexplored in commercial applications at many other countries. The extensive research needed on transgenic cassava for improving yield and reducing disease to become more commercial crop in worldwide.

REFERENCES [1]

[2] [3]

[4] [5]

[6] [7] [8]

Blagbrough, I. S., Bayoumi, S. A., Rowan, M. G., and Beeching, J. R. (2010). Cassava: an appraisal of its phytochemistry and its biotechnological prospects. Phytochemistry, 71(17): 1940-1951. Ngudi, D. D., Kuo, Y. H., and Lambein, F. (2003). Cassava cyanogens and free amino acids in raw and cooked leaves. Food and Chemical Toxicology, 41(8): 1193-1197. Sornyotha, S., Kyu, K. L., and Ratanakhanokchai, K. (2010). An efficient treatment for detoxification process of cassava starch by plant cell wall-degrading enzymes. Journal of bioscience and bioengineering, 109(1): 9-14. Legg, J. P., and Thresh, J. M. (2000). Cassava mosaic virus disease in East Africa: a dynamic disease in a changing environment. Virus research, 71(1): 135-149. Kristensen, S. B. P., Birch-Thomsen, T., Rasmussen, K., Rasmussen, L. V., and Traoré, O. (2014). Cassava as an energy crop: A case study of the potential for an expansion of cassava cultivation for bioethanol production in Southern Mali. Renewable Energy, 66:381-390. http://sattvamji.blogspot.kr/2014/10/78-cassava-or-maniok-root-one-more.html https://ndb.nal.usda.gov/ndb/foods/show/2907?fgcd=&manu=&lfacet=&format=&cou nt=&max=35&offset=&sort=&qlookup=Cassava%2C±raw Ramírez, M. G. L., Satyanarayana, K. G., Iwakiri, S., de Muniz, G. B., Tanobe, V., and Flores-Sahagun, T. S. (2011). Study of the properties of biocomposites. Part I. Cassava starch-green coir fibers from Brazil. Carbohydrate Polymers, 86(4): 1712-1722.


Potential Uses of Cassava Products and Its Future Challenging Opportunities [9]

[10]

[11]

[12]

[13]

[14]

[15]

[16]

[17]

[18] [19]

[20]

[21]

267

Lomelí-Ramírez, M. G., Kestur, S. G., Manríquez-González, R., Iwakiri, S., de Muniz, G. B., and Flores-Sahagun, T. S. (2014). Bio-composites of cassava starch-green coconut fiber: Part II—Structure and properties. Carbohydrate polymers, 102: 576-583. Souza, A. C., Benze, R. F. E. S., Ferrão, E. S., Ditchfield, C., Coelho, A. C. V., and Tadini, C. C. (2012). Cassava starch biodegradable films: Influence of glycerol and clay nanoparticles content on tensile and barrier properties and glass transition temperature. LWT-Food Science and Technology, 46(1): 110-117. Matsui, K. N., Larotonda, F. D. S., Paes, S. S., Luiz, D. D. B., Pires, A. T. N., and Laurindo, J. B. (2004). Cassava bagasse-Kraft paper composites: analysis of influence of impregnation with starch acetate on tensile strength and water absorption properties. Carbohydrate Polymers, 55(3): 237-243. Kampeerapappun, P., Aht-ong, D., Pentrakoon, D., and Srikulkit, K. (2007). Preparation of cassava starch/montmorillonite composite film. Carbohydrate Polymers, 67(2): 155-163. Farias, F. O., Jasko, A. C., Colman, T. A. D., Pinheiro, L. A., Schnitzler, E., Barana, A. C., and Demiate, I. M. (2014). Characterisation of Cassava Bagasse and Composites Prepared by Blending with Low-Density Polyethylene. Brazilian Archives of Biology and Technology, 57(6): 821-830. Tantatherdtam, R., Tran, T., Chotineeranat, S., Lee, B. H., Lee, S. N., Sriroth, K., and Kim, H. J. (2009). Preparation and Characterization of Cassava Fiber-Based Polypropylene and Polybutylene Succinate Composites. Kasetsart J (Nat Sci), 43: 245251. Raabe, J., Fonseca, A. D. S., Bufalino, L., Ribeiro, C., Martins, M. A., Marconcini, J. M., and Tonoli, G. H. D. (2015). Biocomposite of cassava starch reinforced with cellulose pulp fibers modified with deposition of silica (SiO 2) nanoparticles. Journal of Nanomaterials, 2015: 6. de Moraes, J. O., Scheibe, A. S., Sereno, A., and Laurindo, J. B. (2013). Scale-up of the production of cassava starch based films using tape-casting. Journal of Food Engineering, 119(4): 800-808. Versino, F., López, O. V. and García, M. A. (2015). Sustainable use of cassava (Manihot esculenta) roots as raw material for biocomposites development. Industrial Crops and Products, 65: 79-89. Kaewtatip, K., and Tanrattanakul, V. (2012). Structure and properties of pregelatinized cassava starch/kaolin composites. Materials & Design, 37: 423-428. Keeler, B. L., Krohn, B. J., Nickerson, T. A., and Hill, J. D. (2013). US federal agency models offer different visions for achieving renewable fuel standard (RFS2) biofuel volumes. Environmental science & technology, 47(18): 10095-10101. Kosugi, A., Kondo, A., Ueda, M., Murata, Y., Vaithanomsat, P., Thanapase, W., and Mori, Y. (2009). Production of ethanol from cassava pulp via fermentation with a surface-engineered yeast strain displaying glucoamylase. Renewable Energy, 34(5): 1354-1358. Sriroth, K., Piyachomkwan, K., Wanlapatit, S., and Nivitchanyong, S. (2010). The promise of a technology revolution in cassava bioethanol: From Thai practice to the world practice. Fuel, 89(7): 1333-1338.


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[22] Dai, D., Hu, Z., Pu, G., Li, H., and Wang, C. (2006). Energy efficiency and potentials of cassava fuel ethanol in Guangxi region of China. Energy Conversion and Management, 47(13): 1686-1699. [23] Elemike, E. E., Oseghale, O. C. and Okoye, A. C. (2015). Utilization of cellulosic cassava waste for bio-ethanol production. Journal of Environmental Chemical Engineering, 3(4): 2797-2800. [24] Wei, M., Zhu, W., Xie, G., Lestander, T. A., and Xiong, S. (2015). Cassava stem wastes as potential feedstock for fuel ethanol production: A basic parameter study. Renewable Energy, 83: 970-978. [25] Benvenga, M. A. C., Librantz, A. F. H., Santana, J. C. C., and Tambourgi, E. B. (2016). Genetic algorithm applied to study of the economic viability of alcohol production from Cassava root from 2002 to 2013. Journal of Cleaner Production, 113: 483-494. [26] Papong, S., and Malakul, P. (2010). Life-cycle energy and environmental analysis of bioethanol production from cassava in Thailand. Bioresource technology, 101(1): S112-S118. [27] Amutha, R., and Gunasekaran, P. (2001). Production of ethanol from liquefied cassava starch using co-immobilized cells of Zymomonas mobilis and Saccharomyces diastaticus. Journal of bioscience and bioengineering, 92(6): 560-564. [28] Shanavas, S., Padmaja, G., Moorthy, S. N., Sajeev, M. S., and Sheriff, J. T. (2011). Process optimization for bioethanol production from cassava starch using novel ecofriendly enzymes. Biomass and Bioenergy, 35(2): 901-909. [29] Moshi, A. P., Hosea, K. M., Elisante, E., Mamo, G., Önnby, L., and Nges, I. A. (2016). Production of raw starch-degrading enzyme by Aspergillus sp. and its use in conversion of inedible wild cassava flour to bioethanol. Journal of bioscience and bioengineering, 121(4): 457-463. [30] Liu, Q., Cheng, H., Wu, J., Chen, X., Ying, H., Zhou, P., and Chen, Y. (2014). LongTerm Production of Fuel Ethanol by Immobilized Yeast in Repeated-Batch Simultaneous Saccharification and Fermentation of Cassava. Energy & Fuels, 29(1): 185-190. [31] Raj, V. and Prabha, G. (2015). Synthesis, characterization and in vitro drug release of cisplatin loaded Cassava starch acetate–PEG/gelatin nanocomposites. Journal of the Association of Arab Universities for Basic and Applied Sciences. [32] Simi, C. K., and Abraham, T. E. (2007). Hydrophobic grafted and cross-linked starch nanoparticles for drug delivery. Bioprocess and biosystems engineering, 30(3): 173180. [33] Rajan, A., and Abraham, T. E. (2006). Enzymatic modification of cassava starch by bacterial lipase. Bioprocess and Biosystems Engineering, 29(1): 65-71. [34] Pereira, A. G., Fajardo, A. R., Nocchi, S., Nakamura, C. V., Rubira, A. F., and Muniz, E. C. (2013). Starch-based microspheres for sustained-release of curcumin: preparation and cytotoxic effect on tumor cells. Carbohydrate polymers, 98(1): 711-720. [35] Souza, A. C., Goto, G. E. O., Mainardi, J. A., Coelho, A. C. V., and Tadini, C. C. (2013). Cassava starch composite films incorporated with cinnamon essential oil: Antimicrobial activity, microstructure, mechanical and barrier properties. LWT-Food Science and Technology, 54(2): 346-352.



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[36] Mbey, J. A., Hoppe, S., and Thomas, F. (2012). Cassava starch–kaolinite composite film. Effect of clay content and clay modification on film properties. Carbohydrate Polymers, 88(1): 213-222. [37] Zainuddin, S. Y. Z., Ahmad, I. and Kargarzadeh, H. (2013). Cassava starch biocomposites reinforced with cellulose nanocrystals from kenaf fibers. Composite Interfaces, 20(3): 189-199. [38] Phan, T. D., Debeaufort, F., Luu, D., and Voilley, A. (2005). Functional properties of edible agar-based and starch-based films for food quality preservation. Journal of Agricultural and Food Chemistry, 53(4): 973-981. [39] Tumwesigye, K. S., Oliveira, J. C., and Sousa-Gallagher, M. J. (2016). New sustainable approach to reduce cassava borne environmental waste and develop biodegradable materials for food packaging applications. Food Packaging and Shelf Life, 7: 8-19. [40] Bangyekan, C., Aht-Ong, D., and Srikulkit, K. (2006). Preparation and properties evaluation of chitosan-coated cassava starch films. Carbohydrate Polymers, 63(1): 6171. [41] Souza, C. O., Silva, L. T., Silva, J. R., López, J. A., Veiga-Santos, P., and Druzian, J. I. (2011). Mango and acerola pulps as antioxidant additives in cassava starch bio-based film. Journal of agricultural and food chemistry, 59(6): 2248-2254. [42] Reis, L. C. B., de Souza, C. O., da Silva, J. B. A., Martins, A. C., Nunes, I. L., and Druzian, J. I. (2015). Active biocomposites of cassava starch: the effect of yerba mate extract and mango pulp as antioxidant additives on the properties and the stability of a packaged product. Food and Bioproducts Processing, 94: 382-391. [43] Teodoro, A. P., Mali, S., Romero, N., and de Carvalho, G. M. (2015). Cassava starch films containing acetylated starch nanoparticles as reinforcement: Physical and mechanical characterization. Carbohydrate polymers, 126: 9-16. [44] Versino, F., and García, M. A. (2014). Cassava (Manihot esculenta) starch films reinforced with natural fibrous filler. Industrial Crops and Products, 58: 305-314. [45] Chinma, C. E., Ariahu, C. C., and Abu, J. O. (2014). Shelf Life Extension of Toasted Groundnuts through the Application of Cassava Starch and Soy Protein-Based Edible Coating. Nigerian Food Journal, 32(1): 133-138. [46] Pelissari, F. M., Grossmann, M. V., Yamashita, F., and Pineda, E. A. G. (2009). Antimicrobial, mechanical, and barrier properties of cassava starch− chitosan films incorporated with oregano essential oil. Journal of Agricultural and Food Chemistry, 57(16): 7499-7504. [47] Taylor, N., Kent, L., and Fauquet, C. (2004). Progress and challenges for the deployment of transgenic technologies in cassava.





Chapter 14

UTILIZATION OF MODIFIED CASSAVA FLOUR AND ITS BY-PRODUCTS Setiyo Gunawan , Zikrina Istighfarah, Hakun Wirawasista Aparamarta, Firdaus Syarifah and Ira Dwitasari *

Department of Chemical Engineering, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia

ABSTRACT Cassava is an important component in the diets of more than 800 million people around the world. It is kind of tropic and sub-tropic plant. It is able to grow in lessnutrition soil. In a dry land, cassava sheds its leaves to keep it damp and produces new leaves in the rainy season. Otherwise, cassava can not survive in cold weather but it can grow very well in the area with pH 4-8. Cassava needs at least 5 months in the summer for producing ripe cassava. The aim of this chapter is to discuss the proximate composition, production, application, and modification process of cassava roots as well as their future perspective. The typical important parameters for proximate composition of cassava are protein, lipids, fibre, starch, cyanide acid and ash contents. The carbon to nitrogen ratio (C/N ratio) of dried fresh cassava roots is also important parameter for microbial activities within fermentation process. The development of new utilization techniques of cassava roots has gained increasing importance in chemical, food, and pharmaceutical industries, due to their content of economically-valuable compounds, the necessity of environmental friendly process, global food and energy security. There are several different methodologies for enhancing detoxification and improving the quality of cassava flour, such as fermentation process (liquid, solid state, submerged, culture and spontaneous fermentations), different microorganisms (yeast, fungi and bacteria) and different additional nutrients (with and without nutrients). Moreover, lactid acid is produced as by-product during the fermentation. This is also interesting topic due to the potential application of lactic acid for the production of biodegradable polymers. Another, the analysis methods of the compounds in cassava roots are also a challenging * Corresponding Author address; Email: [email protected].


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S. Gunawan, Z. Istighfarah, H. Wirawasista Aparamarta et al. work. Few analytical methods are available to provide a detailed and simpler analysis. It is of great interest if new utilization of cassava roots and analysis methods of the compounds in cassava roots are available to establish all products during the fermentation.

Keywords: cassava, cyanide acid, fermentation, lactic acid, protein, starch

INTRODUCTION Cassava came from the tropical part of America continent, precisely from Brazil. Its deployment reaches all around the world, among others are Africa, Madagascar, India, Indonesia, and China (Achi and Akoma, 2006). This plant is growing well under critical conditions of climate and soil, high resistance to diseases, and flexibel harvesting date, allowing farmers to keep the roots in the ground until needed. Moreover, both leaves and roots can be processed into many kinds of foods. Cassava roots have a high content of fiber and carbohydrate but low protein content. Cassava leaves even have higher protein content than that of cassava roots, because they contain amino metionin acid (Richana, 2012).

CLASSIFICATION OF CASSAVA According to Lingga (1986), depend on its age, cassava divided into two groups: shortlived and long-lived cassavas. Short-lived cassava only has 5-8 months of age from planting to harvesting. At this range, cassava production is optimum. If it is harvested longer than its effective age, the roots are woody. Another, long-lived cassava has 12-18 months of age. Before this range, its tubers become too small. As a defense mechanism against predators, cassava produces two cyanogenic glucosides: linamarin and a small amount of lotaustralin (methyl linamarin) as can be seen in Figure 1. These cyanogens are distributed widely throughout the plant, with large amounts in the leaves and the root cortex (skin layer), and generally smaller amounts in the root parenchyma (interior) (Montagnac and Davis, 2009). Hydrogen cyanide (HCN) is released from the cyanogenic glycosides when fresh plant material is macerated as in chewing, which allows enzymes and cyanogenic glycosides to come together, releasing hydrogen cyanide. Consumption of cassava and its products that contain large amounts of cyanogens may cause cyanide poisoning with symptoms of vomiting, nausea, dizziness, stomach pains, weakness, headache and diarrhea and occasionally death (Cardoso et al., 2005; Nhassico et al., 2008). Cumbana et al. (2007) reported that high cyanide acid is thought to be the major contributing cause of konzo, an irreversible paralysis of the legs in women of child-bearing age and children. Another, there are many varieties of cassava with cyanide content which varies based on the suitability for growing and nutrients consumed. Kobawila et al. (2005) reported that according to the cyanide content in cassava roots, cassava is classified into 3 categories: high, moderate-, and non-toxics varieties with more than 100, 50-100, and less than 50 mg/kg, respectively. Akintonwa et al. (1994) mentioned that, the deathly dose consuming of cyanide


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acid is 0.5 mg per kg of body weight. They also mentioned that bitter cassava variety is more resistant to drought, more readily available and cheaper. The cyanide acid content of bitter cassava is about 50-400 mg/kg, meanwhile the sweet one is 15-50 mg/kg. In so-called sweet cassava, the roots contain only a small amount of cyanogens, therefore after peeling, these roots can be safely boiled and eaten, as occurs in the South Pacific, such as Manihot esculenta Cranz. The bitter taste of bitter cassava is due to high content of cyanide, such as Manihot utilissima Pohl and Manihot glaziovii Muell. These roots must be processed before consumption to reduce the amount of toxic cyanogens to a safe level. The World Health Organization (WHO) has set the safe level of cyanide content in cassava flour at 10 ppm (FAO, 1991; SNI, 2011). CH2OH O

H

CH3

H O

H

OH

H

OH H

C CN

OH

(a) CH2OH O

H

CH3

H OH

O

H H

OH H

C

CH3

CN

OH

(b) Figure 1. Linamarin (a) and lotaustralin (b) structures.

PROXIMATE COMPOSITION OF CASSAVA Indonesia is a tropical region that is rich in natural resources, one of which is tuber root, such as cassava (M. esculenta). Cassava roots are tuber or root of a tree shaped like a cylinder that ends narrowed with an average diameter of 2-5 cm and a length of about 20-50 cm as can be seen in Figure 2 (Jayasuriya, 2015). Cassava is one of foodstuff which has been consumed for long time by Indonesian people. In Indonesia, it was introduced by Portuguese in 16th century. Furthermore, it was planted commercially around 1810s and spread in 1914-1918 (Lingga, 1990). It become an alternative substitute of staple food because Indonesia was experiencing rice shortage. Cassava reaches the top 4th on staple food list in developing countries after rice, wheat, and corn (Bokanga, 1995). It gives nutrition and energy for more than 800 million people


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S. Gunawan, Z. Istighfarah, H. Wirawasista Aparamarta et al.

(Bokanga, 1995). Recently, cassava becomes the 3rd staple food after rice and corn in Indonesia. In 2005, Indonesia was the 3rd largest cassava roots producer countries (13.300.000 tons) after Brazil (25.554.000 tons), and Thailand (13.500.000 tons), then followed by Nigeria (11.000.000 tons), India (6.500.000 tons) from total world production (122.134.000 tons). Indonesia produced 21.756.991 tons cassava roots in 2008, and then increased up to 24.044.025 tons in 2011, however decreased to 23.627.955 tons in 2013 (Statistic Indonesia, 2014).

Figure 2. Manihot esculenta Cranz.

Cassava’s nutrition consist of carbohydrate, lipid, protein, fiber, and ash. The proximate, minerals, and anti-nutrients compositions of dried cassava roots are shown in Table 1, 2 and 3, respectively. Cassava roots are considered as low price and quality raw materials, such as low in protein, minerals and vitamins contents (Onwueme, 1978; Aletor, 1993). Hahn (1992) reported that the low price of cassava roots is also affected by the properties of fresh cassava roots are easily damaged due to the presence of tannic acid, a substance that can cause colors in processed cassava products. Cassava roots contain a little protein, but that protein does contain essential amino acids, such as methionine, cystine and cysteine. Protein is one of bio-macromolecule that has important role for living things. According to Adams and Ray (1988), protein is molecular unit of amino acids containing carbon, hydrogen, oxygen, nitrogen, and sulphur. Amino acids



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itself is divided into two: acid (oxygen, carbon, sulfur) and amino (nitrogen and hydrogen) which attach in carbon atom. Main function of protein is forming cell structure and biocatalyst for chemical reactions in metabolism. Table 1. Proximate composition (wt.%) of cassava roots (Manihot esculenta) No 1

Protein 3.20

Lipids 0.80

Fiber 2.67

Ash 0.80

Carbohydrates 92.53

2

2.63

0.79

2.63

1.84

92.11

3

3.60±0.10

3.60±0.10

3.70±0.2

1.90±0.2

87.2±0.2

4

2.80-3.20

2.30-2.70

6.1-7.8

NAa

NA

5

0.31-1.41

0.77-4.62

0.70-2.20

0.87-1.67

53.60-75.50

6 7 8 9 10

2.37 0.49 1.46 3.38 -

0.40 0.13 NA 0.68 89,4%

7.48 0.15 5.61 4.34 -

NA 0.24 0.90 NA 98,4%

90.00 98.40 92.03 91.61 82%

11

1.93±0.04

0.66±0.01

4.24±0.05

0.69±0.03

92.48±1.14

aNot

References Depkes RI (1981) Westby and Choo, 1991 Akindahunsi et al. (1999) Boonnop et al. (2009) Apea-Bah et al. (2011) Ahaotu et al. (2011) De Silva, 2013 Moshi, 2014 USDA, 2014 Ogunnaike, 2015 Gunawan et al., 2015

available.

Lipids are molecules found in living things. They are substances that dissolve in organic solvents, such as chloroform, hydrocarbon and alcohol instead of water. They may contain acyglycerols, free fatty acids, gums, plant pigments, wax esters, and aldehydes. Fibre also consists of polysaccharides, such as cellulose, hemicellulose, lignin, pectin, and other components associated with the fibrous carbohydrates. Moreover, carbohydrates consist of sugars, and starches. It was observed that starches content in cassava roots is about 83-89.4% (Montagnac and Davis, 2009; Moshi, 2014; Gunawan et al., 2015). Starch consists of two separable fraction, soluble fraction called amylose and unsoluble fraction called amylopectin (Hee-Young, 2005). Starch composed of at least three main components: 15-30% amylose, 70-85% amylopectin and 5-10% other materials (Greenwood and Munro, 1979). The quantity of inorganic materials or minerals knowns as ash. Moreover, carbon to nitrogen ratio is very important for microbial activities within fermentation process. Microorganisms use the carbon from organic matters (carbohydrates) as a source for energy and require nitrogen from protein and other nutrients for reproduction. Gunawan et al. (2015) reported that carbon to nitrogen ratio of dried fresh cassava is 28.41. The variability of proximate, minerals, and anti-nutrients compositions of cassava roots was attributed to cassava cultivar, harvesting age, and diversity of agronomic factors. Anti-nutritions are subtances contained in food that lead poisoning in human when consumed, such as cyanide, phytate, and tannin. Cyanide is the most toxic factor and should be limited for consumption. Cyanide is harmfull for cell metabolism by hampering Cytrochrome oxidase in human body. Peeling and cooking treatments ensure that cassava is able to be consumed safely (Nuwamanya et al., 2008).


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Phytate is another molecule with high concentratiom found in cassava (Table 3). Phytate structure is shown in Figure 3. It is able to bind cation, such as magnesium, calcium, iron, zinc. It also bothers mineral absorption (Montagnac, 2009). Moreover, polyphenol (tanin) increases as the age of cassava (Figure 4). Polyphenol in the human body forms unsaturated complex molecule with divalen ion, such as iron, zinc, and copper. Tanin also deactivate thyamine, and bothers the starch and protein digestion. The other anti-nutrient molecule is oxalate, affects bioavailability and inhibit the digestion system in stomach. Table 2. Minerals and vitamin contents (ppm) of Cassava roots (Manihot esculenta)

Component Ca P Fe Cu K Mg Mn Na Zn Vitamin B1 Vitamin C aNot available.

Depkes RI, 1981

Akindahunsi et al., 1999

Boonnop et al., 2009

Moshi, 2014

USDA, 2014

Gunawan, et al., 2015

33 40 0.7 NA NA NA NA NA NA 0.06 30

167.1 NA 22.5 NA 555.5 277.5 NA 513.7 57.5 NA NA

1.31-1.35 0.7-0.73 NA NA NA NA NA NA NA NA NA

NAa 42 1,4 2,6 1 6,3 24 1,9 9,6 NA NA

16 27 0.27 0.10 271 21 0.38 14 0.34 0.09 20.6

38.55 NA 2.95 NA NA NA NA NA NA NA NA

Table 3. Anti-nutrient content of Cassava roots (Manihot esculenta) (mg/Kg) No HCN 1 14.9 2 21 3 13.83 4 17.5 ± 1.26 aNot available.

Tannin 0.1 NA a NA NA

Phytate 662.8 NA NA NA

H2O3PO

Oxalate NA NA NA NA

References Akindahunsi et al., 1999 Moshi, 2014 Ogunnaike, 2015 Gunawan, et al., 2015

H2O3PO H2O3PO

H2O3PO H2O3PO H2O3PO Figure 3. Phytate structure.



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Figure 4. Tanin structure.

FERMENTATION Word “fermentation” came from Latin language “fervere” which means to boil. Fermentation is a metabolic process that converts sugar to acids, gases, or alcohols. It is also used more broadly to refer to the bulk growth of microorganisms on a growth medium, often with the goal of producing a specific chemical product. In definition, fermentation is a chemical changes process in organic substrate through enzyme activity produced by microorganisms. Microorganisms can ferment various substrates; the end-products depend on the particular microorganisms, the substrates, and the enzymes that are present and active. Chemical analyses of these end-products are useful in identifying microorganisms. The two main types of fermentation are alcoholic and lactic acid fermentation (Tortora et al., 2010). In alcoholic fermentation, substrates are converted into ethanol with the production of carbon dioxide, whereas in lactic fermentation, substrates are converted into lactic acid, and there is no production of carbon dioxide. Alcohol fermentation is carried out by a number of bacteria and yeasts. The ethanol and carbon dioxide produced by the yeast Saccharomyces (sak-ii-romi'ses). They are waste products for yeast cells but are useful to humans. Moreover, two important of lactic acid bacterias are Streptococcus and Lactobacillus. Food fermentation is a product of microorganism’s activities, such as bacteria, leavened, and mold. Microorganisms can produce favorable changes either adverse changes. The most substantial fermentation microorganisms of food are lactic acid bacteria, acetic acid bacteria, and alcohol leavened (Suprihatin, 2010). Liquid, submerged and solid state fermentations are age-old techniques based on water level that used for the preservation and manufacturing of foods. During the second half of the twentieth century, liquid state fermentation developed on an industrial scale to manufacture vital metabolites, such as antibiotics. It is an ideal for the growing of unicellular organisms,


278


such as bacteria or yeasts. Submerged fermentation is a method of manufacturing biomolecules in which enzymes and other reactive compounds are submerged in a liquid, such as alcohol, oil or a nutrient broth. Another, solid state fermentation uses culture substrates with low water levels (reduced water activity), which is particularly appropriate for mould. The methods used to grow filamentous fungi using solid state fermentation allow the best reproduction of their natural environment. Depend on microorganisms origin, fermentation can be divided into two groups: spontaneous and culture fermentations. Spontaneous fermentation, food fermentation in which no microorganism added in the form of neither starter nor yeast, such as lafun production, Nigerian traditional food. Natural microorganisms which are active in the fermentation process can grow well spontaneously because the ambient condition is good for the growth. Lactobacillus spp. and Leuconostoc spp. are some of the organism that are involved in spontaneous fermentation. Besides, organisms which contribute in culture fermentation are Saccharomyces cerevisiae, Rhizopus oryzae, Aspergillus niger, Endomycopsis burtonii, Mucor sp., Candida utilis, Saccharomycopsis fibuligera, and Pediococcus, sp. The hydrolysis of cyanogenic glucosides takes place during the fermentation. The cyanide content decreases during the fermentation by more than 70% through the activities of the bacterial produced linamarase, allowing the hydrolysis of cyanogenic glucosides. Certain lactic bacterias present in the environment of fermentation that are resistant to the strong cyanide concentrations of between 200 and 800 ppm.

UTILIZATION OF CASSAVA As a commodity, cassava can be processed to produce many kind of products, such as cassava leaves, cassava chip, cassava flour, sweeteners, starch, ethanol, and modified cassava flour (mocaf).

1. Cassava Roots and Leaves as Vegetables Both the cassava roots and leaves are edible and most commonly eaten as vegetables. Young tender cassava leaves are a good source of dietary proteins and vitamin K. Cassava leaves contain 17-34% of proteins in dry basis and pH around 8.5 (Kobawila et al., 2005). Vitamin-K has a potential role in bone mass building by promoting osteotrophic activity in the bones (Buitrago, 1990). It also has established role in the treatment of Alzheimer's disease patients by limiting neuronal damage in the brain (Allison, 2001). Cassava roots are popular ingredients in fries, stew-fries, soups, and savory dishes all over the tropic regions. In general, cassava roots are fried in oil until brown and crisp and served with salt, and pepper seasoning as a snack (Bempong et al., 2014). Moreover, there are also used as the ingredients of animal feeds (Oppong-Apane, 2013). Cassava roots are sun-dried for one to two days until they have final dry matter content of less than 85%. They are valued as a good roughage source for ruminants, such as cattle.



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2. Cassava Starch (Tapioca Starch) Cassava starch, also known as tapioca starch, is a starchy white flour that has a slight sweet flavor to it. It is extracted from the cassava roots through a process of washing and pulping. The wet pulp is then squeezed to extract a starchy liquid. Once all the water evaporates from the starchy liquid, the tapioca starch remains (FAO, 2016). It is used in both its original form and its other modified forms in various industries: food and beverage, textile, adhesives, paper, plywood, medicine, and biodegradable material industries. The food industries constitute one of the largest consumers of starch and starch products. Cassava starch is used for producing instant noodle, sago, seasoning sauce and monosodium glutamate. It is also used for producing glucose and fructose which are used as the sweeteners in the beverage industry. One of the advantages of cassava starch when compared to corn starch is the absence of the undesired “cereal flavor.” This makes cassava starch preferred for application in many processed foods, with particular interest in bland flavored products. Other factors that make cassava starch as a key ingredient for food industry and also for other kinds of applications are its particular physicochemical behavior when cooked in aqueous dispersion, producing high clarity and high viscosity pastes (Che et al., 2007), as well as presenting a low gelatinization temperature and low tendency to retrogradation when compared to cereal starches. The gelatinization temperature is lower and its apparent viscosity higher than that of corn starch at the same concentration, what represents an advantage for some applications. After cooking, cassava starch paste has lower tendency to retrogradation, what is often a desired property for industrial uses. Although cassava starch has several advantages when compared to corn starch, it also has limitations like being unstable to cooking and to acidity, as other native starches (Takizawa et al., 2004). In the textile industry, cassava starch is used in three main areas: sizing, finishing and printing. Properties of the starch used are abrasion resistance, flexibility, ability to form a bond to the fiber, ability to penetrate the fiber bundle to some extent and ability to have enough water holding capacity so that the fiber itself does not rob the size of its hydration. Moreover, cassava starch is a popular base for adhesives, particularly those designed to bond paper in some form to itself or to other materials, such as glass, mineral wool, and clay (Agboola et al., 1990). It can be also used as a binder or adhesive for non-paper substances, such as charcoal in charcoal briquettes, mineral wool in ceiling tiles and ceramics before firing. Cassava starch adhesives are more viscous and smoother working. They are fluid, stable glues of neutral pH that can be easily prepared and can be combined with many synthetic resin emulsions. In the pharmaceutical industry, cassava strach is used as a disintegrant and binder. Disintegrants enable tablets and capsules to break down into smaller fragments (dissolve) so that the drug can be released for absorption. Starch is used to influence or control the characteristics, such as texture, moisture, consistency and shelf stability. It can be used to bind or to disintegrate, to expand or to densify, to clarify or to opacify, to attract moisture or to inhibit moisture, to produce smooth texture or pulpy texture, and soft coatings or crisp coatings. It can be used to stabilize emulsions or to form oil resistant films (Miyazaki et al., 2006). Another, cassava starch can be transformed as product by mean of adding the biodegradable substance to be in place of plastic.


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3. Cassava Flour Cassava flour is an alternative to traditional wheat flours and has a variety of uses in baking. It helps bind gluten free recipes and improves the texture of baked goods. It helps add crispness to crusts and chew to baked goods. It is an extremely smooth flour, which makes for a great thickener in sauces, pies and soups since it never discolors and contains no discernible taste or smell. Table 4. The proximate composition of wheat, cassava and modified cassava flours (SNI standard, 2011) Composition Moisture, % Protein, % Fibre, % Lipid, % Carbohydrate, % Ash, % Total Titrable Acidity HCN (mg/kg) available.

Wheat flour Max 14.5 Min 7.0 Max 2.0 NAa 60-70% Max 0.7 Max 5.0 (mg KOH / 100 g) Max 10

Cassava flour Max 12 NA Max 4.0 NA 75% Max 1.5 NA Max 10

MOCAF Max 13 Min 7.0 Max 2.0 NA NA Max 1.5 Max 4.0 (mL NaOH 1N/100 g) Max 10

aNot

Cassava flour is from freshly harvested roots. The roots are peeled, washed and cut into chips. The cassava chips are sun‐dried, milled into a fine powder and packaged in moisture proof materials. The chipping method is faster and requires the use of only the chipping machine before drying; however, its use is limited to cassava of low cyanogenic potential. The use of casava flour for baking, pastry production and other catering purposes has also been developed and demonstrated to home caterers, bakers and industrial food processors (Falade and Akingbala, 2008). However, it contains a lower protein content than that of wheat flour as can be seen in Table 4 (SNI standard, 2011).

4. Fermented Cassava a. Modified Cassava Flour (Also Knowns as Lafun and Gari Flours in West Africa) Modified cassava flour (mocaf) is a product derived from cassava that uses a principle of modifying cassava flour in fermentation, which produces distinctive characteristics, so it can be used as a food ingredient with a very wide scale. Preliminary experimental results showed that mocaf could be used as raw materials from a variety of foods, ranging from noodles, bakery, cookies and semi-moist food, since the application has a spectrum similar to wheat flour, rice and other starchy materials. Advantages of mocaf: mocaf has aroma and flavor better than that of regular cassava flour, has more color than that of usual cassava flour, and has relatively low prices compared to wheat or rice flours (Sulistyo and Nakahara, 2014). Moreover, it contains a higher protein content than that of cassava flour. Mocaf is expected to be one of the wheat flour alternative substitutes. In Indonesia, mocaf has a good prospect because of the cassava availability and low cost production. There



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are several different methodologies for fermentation process of cassava (liquid, solid state, submerged, culture and spontaneous fermentations), different microorganisms (yeast, fungi and bacteria) and different additional nutrients (with and without nutrients) for enhancing detoxification and improving the quality of cassava flour. The typical important parameters for proximate composition of mocaf are protein, lipids, fibre, starch, cyanide acid and ash contents as shown in Table 4 (SNI standard, 2011). Mocaf can be produced by different methods depending on the locality. The nutrients comparison of mocaf are shown in Table 5. Lafun flour is one of mocaf from south-western part of Nigeria as can be seen in Figure 5 (Rauf, 2015). The flour is made by allowing peeled tuberous roots of cassava steeped in water to ferment naturally (spontaneous fermentation). It is produced by submerged fermentation of peeled sliced cassava roots in water for 3-5 days or by immersing peeled or unpeeled cassava in a stream or stationary water or in an earthenware vessel. It was fermented until the roots become soft after which the fermented cassava was subjected to sun-drying and milling to powder/flour. It was also found that C. manihot, Lactobacillus spp. and Leuconostoc spp. are some of the organisms that are involved in fermentation of cassava to Lafun (Ogunnaike, 2015). The flour is usually prepared as stiff porridge using boiling water, prior to being consumed with soup (Podonou et al., 2009). Gari flour (also known as garri, garry, or gali) is one of mocaf from west africa as can be seen in Figure 6 (International Starch Institute, 2014). Gari flour color is browner than that of lafun. Cassava roots are peeled, washed, and grated or crushed to produce a mash. The mash is placed in a porous bag and weights are placed on the bag for a day to a few days to press excess water out. It is involving spontaneous and solid state fermentations. When the cassava has become dry enough, it is ready for the next step. It is then sieved and fried in a large clay frying pot with or without palm oil. The resulting dry granular garri can be stored for long periods. It may be pounded or ground to make fine flour (Oduah, 2015).

b. Bikedi Bikedi is one of Congo traditional food from fermented cassava roots, involving spontaneous and submerged fermentations. In the first step, freshly harvested cassava roots are peeled and cleaned in the water. They are then immersed in the water for fermentations for 3-6 days at ambient temperature (28 to 32°C). In the second step, the whole roots of cassava (unpeeled) are immersed in the water for fermentations for 3-6 days at ambient temperature (28 to 32°C). After fermentation, the softened cassava product, bikedi, is removed from the water. It contains acid condition with pH around 4 (Kobawilla et al., 2005). c. Ntoba Mbodi Ntoba mbodi is one of Congo traditional food from fermented cassava leaves, involving spontaneous and submerged fermentations. Two weeks to 3 months old cassava leaves were harvested. After harvesting, the cassava leaves are exposed to the sun at ambient temperature for 2-3 h. Stalks and petioles were removed and the leaves cut in fragments. Cut leaves are then cleaned in water, then drained and finally packed in the clean leaves of papaw (Papaya carica) at the rate of 150 g per package for fermentation for 2-4 days. After fermentation, the product, ntoba mbodi, is obtained (Kobawila et al., 2005). Mokemiabeka (2011) reported that proximate composition of Ntoba mbodi are 25% protein, 20% fiber, 13.29% ash and others.


Table 5. Nutrients comparison of modified cassava flour Composition Moisture, % Protein, % Fibre, % Lipids, % Starch, % Ash, % HCN, mg/kg Odor Color Mikroorganism Submerged a Not Available.

Gunawan, et al., 2015 8.83 8.58 2.92 2.55 55.40 0.49 1.8 Normal White L. plantarum Submerged

9.61 2.29 2.53 3.29 71.00 0.47 3.28 Normal White S. cereviseae Submerged

10.42 4.72 2.20 3.36 48.2 0.42 3.17 Normal White R. oryzae Submerged

Ogunnaike, et al., 2015 12.6 1.94 2.0 NA 82.46 1.0 13.2 Normal White natural Submerged

Oboh and Akindahunsi, 2003

Oboh et al., 2002

NAa 10.9 NA 4.5 77.9 NA 9.5 Normal White S. cereviseae Solid state

NA 12.2 NA 5.7 NA NA 9.1 Normal White A. niger Submerged

NA 6.3 NA 3.0 84.5 NA 9.1 Normal Browner S. cereviseae Solid state


NA 7.3 NA 4.0 NA NA 4.1 Normal Browner A. niger Submerged


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Figure 5. Lafun Flour.

Figure 6. Gari flour.

d. Foofoo (Also Known as Fufu, Foufou, Fufuo, and Fofo) Foofoo is one of Nigeria traditional food from fermented cassava roots, involving spontaneous and submerged fermentations. The proximate composition of foofoo can be seen in Table 6. Foofoo production includes peeling, washing and steeping or submerging of cassava roots in water for 3- 4 days. During this period, the retted cassava tubers are softened. The softened pulpy mass is then disintegrated in water and passed through a coarse sieve. This separates the fiber from starch which is allowed to sediment, then the water is decanted. It is then packed into cloth bags and excess water is squeezed out. The resulted meal is white and crumbly which is usually cooked before being eaten. Foofoo is reconstituted by stirring in boiling water to form dough and eaten with favoured sauces (Abriba et al., 2012).


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e. Chikwangue (Cassava Bread) Chikwangue is one of Congo traditional food from fermented cassava roots, which are mainly consumed in the form of cassava bread as can be seen in Figure 7 (Naliaka, 2015). It contains 10.3% protein for composition cassava bread and soya at 80:20 and 12.4% protein for composition cassava bread and peanut at 80:20 (Tajudeen, 2013). Naliaka (2015) reported that proximate of chikwangue is 51.4% moisture, 0% lipid, 1% fibre, and 45% carbohydrates. Chikwangue production includes peeling, washing and submerging of cassava tubers in water for 3-4 days. It is involving spontaneous and submerged fermentations. Chikwangue is a popular starchy food from a recipe for cooking a roll of cassava dough (often times called 'cassava bread') inside a multi-layered wrapping of large fresh leaves (about 7 leaves), tied snugly with palm fibers or string to hold steam inside during cooking. Table 6. The proximate composition of foofoo flours Ojo et al., 2014 Oven dried 8.700.16 1.170.32 0.230.20 0.720.11 88.830.27 0.350.21

Composition Moisture, % Protein, % Fibre, % Lipid, % Carbohydrate, % Ash, % a Not Available

Sun Dried 8.500.23 1.020.41 0.170.13 0.620.09 88.390.33 0.300.17

Solar Dried 8.000.19 1.210.27 0.150.10 0.700.10 88.620.22 0.320.11

Blessing et al., 2013 NAa 3.09% 0.36% 0.18% 95.41% 0.96%

Figure 7. Chikwangue.


Abriba et al., 2012 71.13% 0.14% NA 0.009% 28.64% 0.09%


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f. Tapai Tapai is one of Indonesian traditional food from fermented starchy substrates, such as cassava and white rice, involving solid state and culture fermentations by yeast as shown in Figure 8 (Astawan and Mita, 1991). It contains 0.5% protein, 0.1% lipid, 56.1% moisture and 42.5% carbohydrates (Ganjar, 2003). Cassava is wrapped with leaf and softened (Saleh, 2015). The culture fermentation involves many kind of microorganisms, such as S. Cerevisiae, R. oryzae, E. burtonii, Mucor sp., C. utilis, S. fibuligera, and Pediococcus, sp. (Ganjar, 2003). Tapai fermentation consists three stages of decomposition: (1) starch molecules are split into 10 dextrin and monosaccharaides, using enzymatic hydrolysis process, (2) monosaccharaides are modified into organic acids and alcohol, (3) organic acids are reacted with alcohol forming unique taste of tapai (ester) (Hidayat, 2006).

Figure 8. Tapai.

g. Bioethanol Cassava is used for producing alcohol for the liquor manufacture and the disinfectant. Production of bioethanol is also a global requirement to address the question of energy crisis. Ethanol has the advantages of being renewable, providing cleaner burning and producing no green-house gases compared to conventional fossil fuel. Attempts have been made to use agricultural starch based renewable resources (cassava roots) to produce ethanol. Bioethanol production consists of three major processes as can be seen in Figure 9. At the first step, cassava is obtained from agricultural crops. During the second step, cassava is converted into fermentable sugars by enzymatic degradation (α-amylase and glucoamylase exogenously) or by acid hydrolysis. These simple sugars are then fermented to produce ethanol by yeast, S. cerevisiae. At the final step, ethanol is recovered from the fermentation broth by distillation.


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S. Gunawan, Z. Istighfarah, H. Wirawasista Aparamarta et al. CH2OH

CH2OH H

H

O

H OH

OH

OH

Enzyme H

OH

HOCH2

H

OH

OH

+H20

O

H

OH

OH

HOCH2

O

O

OH

H

OH CH2OH

H

CH2OH

H

OH

H

OH

Fructose

Sucrose

(a) OH

CH2OH O

CH2OH O

O

OH

H+ or

OH

lactase

OH OH

OH

CH2OH

CH2OH

O

O

HO

OH

OH

+

OH

OH HO OH

OH

(b) H2COH o

H OH

O

H

+

H

OH OH

C

Yeast

C

O

OH

OH

CH3 H

CH2

+

2CO2

CH3

OH

2 Pyruvate Glucose

2 Ethanol

(c) Figure 9. Production of bioethanol from cassava: Enzyme degradation(a), acid hydrolysis (b), and ethanol production (c).

ANALYSIS The typical important parameters for proximate composition of mocaf are protein, lipids, fibre, starch, cyanide acid and ash contents. A summary of most analytical techniques used in the quantification of compounds in mocaf is given in Table 7. Moisture content was analyzed using a Halogen Moisture Analyzer. A sample was weighed accurately in a clean and dried crucibile (W1). Then the crucible was introduced into the Halogen Moisture Analyzer and held at 105 oC until constant weight was achieved (W2). The moisture content (M) was calculated as


Utilization of Modified Cassava Flour and Its By-Products M = (W1-W2) / (W1) × 100%

287 (1)

A Soxhlet extractor, equipped with a condenser system, was employed to measure lipids content. The sample was wrapped in filter paper and placed inside the Soxhlet extractor. Neutral lipids, such as fatty acids and acylglycerols, were extracted from the sample with hexane as the solvent. After a predetermined time, the extraction process was stopped, which was designated as the crude oil. The lipids content (L) was calculated as L = {[weight of hexane extract, g] / [weight ofsample, g]} × 100%

(2)

The proteins content was determined by analyzing its nitrogen content (AOAC, 2003). Total protein was determined by multiplying the amount of nitrogen by the 6.25 correction factor (FAO, 2003). A dried sample (W) was transferred into a Kjeidahl digestion flask. Then, a certain volume of concentrated HCl were added to the digestion flask. The flask was swirled in order to mix the contents thoroughly, then placed on heater to digest untill the mixture became clear. Then, distilled water was added and swirled in order to mix the contents thoroughly. Then, a certain volume of NaOH 30% solution and some drops of phenolptalein indicator were added into the Kjeidahl digestion flask. Distillation was finished when there was no flow from digestion flask. The NH3 produced was collected as NH4OH in a conical flask containing 4% boric acid solution with few drops of Conway indicator. The distillate was titrated againts standard HCl 1 N. The crude proteins content (P) was calculated as P = 6.25 ×[(V1-V2) × N ×0.014 × f / W] × 100%

(3)

where V1, V2, N, f, W were the sample titration reading, blank titration reading, HCl normality, sample dilution, and sample weight, respectively. The 0.014 was the mili equivalent of nitrogen. Ash content was determined by AOAC (2003). A clean and empty evaporating dish was heated in a muffle furnace at 600 oC for 1 h, cooled in a desiccator and weighed (W1). A sample was weighed into an evaporating dish. The sample was heated in a muffle furnace at 550 oC for 6 h until it was charred. The result appeared as a gray white ash. It indicates that complete oxidation of all organic matters in the sample had occured. The evaporating dish was cooled and weighed (W2). The percent ash (A) was calculated as A = (W2 - W1) / sample weight × 100%

(4)

Fibers content was determined by AOAC (2003). Moisture free sample was digested using dilute H2SO4 followed by dilute KOH solution. The undigested residue was ignited in a muffle furnace. Weight loss after ignition was considered as crude fiber. A 0,5 g sample (W1) was placed in an evaporating dish along with 150 ml of H2SO4 and some drops of acetone as foam suppresser. The mixture was heated at 100oC until it started to boil. Then, the temperature was reduced to 45oC for 0.5 h. The sediment was filtered and rinsed with distilled water to remove any remaining acid. Afterwards, the same procedure was repeated using KOH instead of sulfuric acid. Filter paper with sediment was dried in an oven at 150oC for 1 h, then transferred into a desiccator, and then weighed (W2). The sediment and filter paper


288


were placed in an evaporating dish and heated in a furnace for 3-4 h, then transferred into a desiccator and then weighed (W3). The crude fibers content (F) was calculated as F = (W2 – W3) / W1× 100%

(5)

Acid method (AOAC,2003) was used to determine starch content of washed and fermented cassava. Briefly, a crushed sample was put into a flask containing distilled water. The mixture was stirred for 1 h and filtered using a Whatman 42 filter paper. The solid phase on the filter paper was washed with distilled water. Furthermore, the solid residue on the filter paper was washed with diethyl ether, and allowed the ether to evaporate. Afterwards, it washed again with 10% ethanol for further release of soluble carbohydrates. The filtrate containing soluble carbohydrates was discarded. The solid residue was transferred into a flask containing distilled water. Then, 25% HCl was added to the flask and heated at 100°C for 2.5 h. After cooled, the mixture was neutralized with 45% NaOH solution. The mixture was filtered by vacuum filtration. The resulting solid phase on the filter paper was wasshed with distillate water. Furthermore, sugar content of the filtrate was analyzed for according to the 3,5-dinitrosalicylic acid (DNS) method. The percentage of starch was determined by multiplying glucose content by factor number of 0.9. The cyanide acid content of fermented cassava was determined by titration (SNI, 2011). Briefly, a fermented cassava was transferred into a Kjeldahl digestion flask containing distilled water. The flask was swirled to mix the contents thoroughly for 2 h and heated to recover cyanide acid as distillate. The distillate was collected in a conical flask containing 2.5% NaOH solution, NH4OH solution and 5% KI solution. The resulting mixture was titrated against 0.02 N AgNO3 until there was a turbidity. A blank was also run through all steps above. The cyanide acid content (HCN) was calculated from the amount of AgNO3 used for titration. HCN (mg/kg) = (V1-V2) × N × 27 / (V3× W)

(6)

where V1, V2, V3, N, and W were the blank titration reading, sample titration reading, distillate volume, AgNO3 normality, and sample weight, respectively. The 27 was the molecular weight of cyanide acid. The lactic acid content of filtrate obtained from fermentation was determined by total titrable acidity (GEA Niro, 2006). Briefly, a sample was transferred into a flask. A few drops of phenolphthalein as indicator was added to the flask. Then, the sample was titrated against 0.2 N NaOH. The lactic acid content (TTA) was calculated as: TTA (mg/ml) = N × V1 × 0.090 / V2

(7)

where N, V1, and V2 were the NaOH Normality, NaOH volume, and sample volume. The 0.090 was the milli equivalent of lactic acid.



289

Table 7. Summary of most analytical techniques used in quantification of compounds in mocaf Compounds Moisture

Techniques Gravimetric method Lowry Method (AOAC)

Protein

Kjeldahl method (AOAC)

Lipids

Soxhlet exraction method (AOAC)

Fiber

Starch

AOAC DNS colorimetric method (AOAC) Acid method, DNS colorimetric method Acid method, HPLC method Spectrophotomeric method Titration (AOAC)

HCN Titration (SNI) Titration Method (AOAC) Lactic acid

References Gunawan et al., 2015 Sulistyo and Nakahara 2013; Emmanuel et al., 2015 Nuwamanya et al.., 2011; Moshi et al., 2014; Gunawan et al., 2015; Ogunnaike et al., 2015; Oduah et al., 2015; Nuwamanya et al..,2011; Gunawan et al., 2015; Ogunnaike et al., 2015; Oduah et al., 2015; Gunawan et al., 2015 Sulistyo and Nakahara 2013 Gunawan et al., 2015 Moshi et al., 2014 Nuwamanya et al..,2011 Hidayat et al., 2002; Emmanuel et al., 2015 Gunawan et al., 2015 Abriba et al., 2012; Sulistyo and Nakahara, 2013; Emmanuel et al., 2015; Gunawan et al., 2015; Ogunnaike et al., 2015; Oduah et al., 2015;

LACTIC ACID Lactic acid is a carboxylic acid widely used as preservative, acidulant, and/or flavouring in food industry. It is also used as a raw material for the production of lactate ester, propylene glycol, 2,3-pentanedione, propanoic acid, acrylic acid and acetaldehyde. The demand for lactic acid production has dramatically increased due to its application as a monomer for poly-lactic acid synthesis, a biodegradable polymer used as a plastic in many industrial applications (Milkos et al., 1994; Barrera et al., 1995; Quintero et al. 2012). In recent years, development of biological control should help improve the safety of products by controlling mycotoxin contamination. Data has actually shown that many lactic acid bacterias can inhibit mould growth and that some of them have the potential to interact with mycotoxins. Dalié et al. (2010) summarized that lactic acid bacterias are promising biological agents for food safety. Moreover, lactic acid can be produced either by fermentation or chemical synthesis. The former route has received considerable interest, due to environmental concerns and the limited nature of petrochemical feedstocks. Thus, 90% of lactic acid produced worldwide is obtained by fermentation. This process comprises the bioconversion of carbohydrates into


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lactic acid in the presence of a microorganism. Cassava rots are promising low-cost substrate as a carbon source for lab and eventually large scale lactic acid biosynthesis. Fermentation couses substantial modification to the physicochemical characteristic of cassava roots. pH is an important parameter in determining the quality of modified cassava flour. pH of 4 or less indicates appreciable level of fermentation and hence starch breakdown. Fermentation also imparts characteristic aroma, flavour and sour taste to the flour. The effect of fermentation time and culture type (L. plantarum, S. cereviseae, and R. Oryzae) on the pH profile of cultivation is shown in Table 8. It can be seen that a relatively high pH is indicate of an unfermented cassava roots and pH value of culture decreases by increasing fermentation time. However, pH profile of culture varies according to the fermentation time within the culture type studied. The final pH for each culture is within the range of 3.87-4.37. Previous work reported that pH profile was decreased with time as a result of more lactate production and accumulation when cultivating R. oryzae without pH control. The final pH for each culture was within the range of 2.0–4.5 (Phrueksawan, 2012). Table 8. pH profile of cultivation of L. plantarum, S. cereviseae, and R. oryzae on cassava roots Fermentation time, (h) 0 12 24 36 48 60 72 84 96

pH L. plantarum 6.02±0.54 4.14±0.05 3.98±0.01 3.89±0.02 3.87±0.03 3.89±0.01 3.90±0.01 3.97±0.02 3.93±0.01

S. cereviseae 6.02±0.54 4.18±0.01 4.10±0.02 4.15±0.01 4.17±0.01 4.17±0.02 4.26±0.01 4.30±0.01 4.37±0.15

R. oryzae 6.02±0.54 4.33±0.50 4.17±0.01 4.11±0.01 4.12±0.01 3.99±0.01 4.02±0.01 3.94±0.03 3.87±0.06

Table 9. The lactic acid production from L. plantarum, S. Cereviseae, and R. Oryzae cultivations on cassava fermentation Fermentation time, (h) 0 12 24 36 48 60 72 84 96

Lactic acid concentration (mg/mL) L. plantarum S. cereviseae 0.02 ±0.00 0.02±0.00 0.30±0.03 0.32±0.02 0.49±0.05 0.45±0.01 0.56±0.02 0.49±0.01 0.68±0.01 0.52±0.01 0.73±0.01 0.52±0.02 0.75±0.01 0.53±0.02 0.84±0.01 0.54±0.01 0.90±0.01 0.55±0.01


R. oryzae 0.01±0.01 0.42±0.01 0.51±0.01 0.57±0.03 0.58±0.01 0.61±0.04 0.61±0.04 0.76±0.01 0.89±0.01


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To verify the above results, the lactic acid content is an important parameter to measure. The effect of fermentation time and culture type (L. plantarum, S. cereviseae, and R. Oryzae) on the lactic acid production is shown in Table 9. It can be seen that conversion from glucose to lactic acid is the critical step in the fermentation on cassava roots. L. plantarum, S. Cereviseae, and R. Oryzae cultivations produced lactic acid within the range of 0.55-0.90 mg/mL. This cause a rapid drop in pH, the environment then became selective against less acid-tolerant microorganisms. Wang et al. (2010) reported that the high L-lactic acid concentration (175.4 g/L) was obtained using 275 g/L of cassava powder concentration (total sugar of 222.5 g/L). This is the highest L-lactic acid concentration from cassava fermentation. It provides an efficient L-lactic acid production process with cheap raw bioresources, such as cassava powder.

REFERENCES Abdallah, M.A., Lei, Z.M., Li, X., Greenwold N., Nakajima, S.T., Jauniaux, E., Rao, C.V., 2004. Human Fetal nongonadal tissues contain human chorionic gonadotropin/ luteinizing hormone receptors. J. Clin. Endocrinol. Metab. 89, 952-956. Abriba, C., Henshaw, E.E., Lenox, J, Eja, M., Ikpoh, I.S., Agbor, B.E., (2012). Microbial succession and odour reduction during the controlled fermentation of cassava tubers for the production of ‘foofoo,’ a staple food consumed popularly in Nigeria. J. Microbiol. Biotech. Res., 2, 500-506. Achi, O.K. and Akoma, N.S., (2006). Comparative Assessment of Fermentation Techniques in the Processing of Fufu, a Traditional Fermented Cassava Product. Pak. J. Nutr. 5, 224229. Adams, A. and Ray, C., (1988). Catering Technology, 1st ed. London: B.T. Bastford Ltd. Agboola, S. O., Akingbala, J. O., Oguntimein, G. B. (1990) Processing of Cassava Starch for Adhesive Production. Nr. 1 S. 12-15. Ahaotu, I., Ogueke, C. C., Owuamanam, C. I., Ahaotu, N. N. and Nwosu, J. N. (2011). Protein improvement in gari by the use of pure cultures of microorganisms involved in the natural fermentation process. Pakistan J. Biol. Sci. 14, 933 – 938. Akihandusi, A.A., Oboh, G., Oshodi, A.A. (1999). Effect of Fermenting Cassava with Rhizopus oryzae on the Chemical Composition of Its Flour and Gari Products. Riv. Ital. Sostanze Grasse, 76, 437-440. Akintonwa, A., Tunwashe, O., Onifade, A., (1994). Fatal and Non-Fatal Acute Poisoning Attributed to Cassava–based Meal. Acta Hortic., 375, 285–288. Aletor, V.A., (1993). Allelochemichal in Plant Food and Feeding Stuffs: Nutrional, Biochemichal and Physiophatological Aspects in Animal Production. Veterinary and Human Toxicology Journal. 35: 57-67. Aletor, V.A (1993) Cyanide in Garri: Distribution of Total, free and bound hydro cyanide acid (HCN) in commercial garri and the effect of fermentation time on its residual cyanide content. Intern. J. Food Sc. Nutr.44, 181-287. Allison, A. C., (2001). The Possible Role of Vitamin K Deficiency in The Pathogenesis of Alzheimer’s Disease and in Augmenting Brain Damage Associated with Cardiovascular Disease. Medical Hypotheses. 57(2), 151–155.


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AOAC, (2003). Official Methods of Analysis. 17th edition, 2 revision. AOAC International. Gaithersburg, Maryland, USA. Apea-Bah, F., Oduro I., Ellis, W. and Safo-Kantanka, (2011). W.J.D.S. 6, 43-54. Aplin, J.D., (1991). Implantation, trophoblast differentiation and hemochorial placentation, Mechanistic evidence in vivo and in vitro. J. Cell. Sci. 99, 681-692. Aplin, J.D., Haigh, T., Jones, C.J., Church, H.J., Vićovac, L., (1999). Development of cytotrophoblast columns from explanted first-trimester human placental villi, role of fibronectin and integrin alpha5beta1. Biol. Reprod. 60, 828-38. Badan Standarisasi Nasional. 2009. SNI-7125-2009 Standar Mutu Tepung Terigu. Jakarta. Badan Standarisasi Nasional. 2011. SNI-7622-2011 Standar Mutu Tepung MOCAF. Jakarta. Bahado-Singh, R.O., Oz, A.U., Kingston, J.M., Shahabi, S., Hsu, C.D., Cole, L.A., (2002). The role of hyperglycosylated hCG in trophoblast invasion and the prediction of subsequent preeclampsia. Prenat. Diagn. 22, 478-83. Bempong, E.K., Constance, A.S., Sarkodie, N.A., (2014). Enhancing Food Tourism in Ghana Through Indigenous Dishes: A Case Study of the Brong-Ahafo Region, Ghana. I.J.I.A.R, 2, 83 – 96. Berndt, S., Blacher, S., d'Hauterive, PS., Thiry, M., Tsampalas, M., Cruz, A., Pequeux, C., Lorquet, S., Munaut, C., Noel, A., Foidart, J.M., (2009). Chorionic gonadotropin stimulation of angiogenesis and pericyte recruitment. J. Clin. Endocrinol. Metab. 94, 4567-4574. Blessing, N., Ishola, Chikwendu, O. (2013). Effect of blending on the Proximate, Pasting and Sensory Attributes of Cassava-African yam Bean Fufu Flour. I.J.S.E.R. 3, 2250-3153. Bokanga, M., (1995). Biotechnology and Cassava Processing in Africa. Food Technol. 49, 88-90. Boonnop, K., M. Wanapat, N. Nontaso, and S. Wanapat. (2009). Enriching nutritive value of cassava root by yeast fermentation. Sci. Agric. 66, 629-633. Buitrago, A.J.A., (1990). La Yuca en la Alimentaciόn Animal. Centro Internacional de Agricultural Tropical (CIAT), Cali, Colombia. 446-449. Burton G.J., (2004). Placental oxidative stress, From miscarriage to preeclampsia. J. Soc. Gynecol. Invest. 11, 342-52. Cardoso, A.P., Mirione, E., Ernesto, M., Massaza, F., Cliff, J., Haque, M.R. and Bradbury, J.H., (2005). Processing Cassava Roots to Remove Cyanogens. J. Food Comp. Anal., 18(5): 451-460. Che, L. M. Li, D., Wang, L., Chen, X. D., and Mao, Z. (2007). Micronization and hydrophobic modification of cassava starch. Int. J. Food Prop. 10, 527-536. Cumbana, A., Mirione, E., Cliff, J. and Bradbury, J.H., (2007). Reduction of Cyanide Content of Cassava Flour in Mozambique by The Wetting Method. Food Chem. 101: 894-897. Dalié, D.K.D., Deschamps, A.M., Richard-Forget, F. (2010). Lactic acid bacteria – Potential for control of mould growth and mycotoxins: A review. Food Control 21: 370–380. Emmanuel, N.O., Olufunmi, A.O., Elohor, E.P. (2015). Effect of Fermentation Time on the Physico –Chemical, Nutritional and Sensory Quality of Cassava Chips (Kpo-Kpo Garri) a Traditional Nigerian Food. American Journal of BioScience. 3, 59-63 Health Department (Depkes) Of Indonesia (1981). Composition list of food resource. Bhatara Karya Aksara, Jakarta. FAO/WHO. (1991). Joint FAO/WHO food standards programme. Codex Alimentarius Commission XII (Suppl. 4). Rome; FAO.



293

FAO (2016). Cassava Processing. http://www.fao.org/docrep/ x5032e/ x5032E02.htm. Indonesian Statistics., (2014). Perkembangan Produksi Singkong Indonesia Tahun 20092013. http://www.bps.com. Falade, K. O., and Akingbala, J. O. (2008). Improved Nutrition and National Development Through the Utilization of Cassava in Baked Foods. Using Food Science and Technology, IUFoST: Chapter 10. Ganjar I., (2003). Tapai from Cassava and Sereals, First International Symposium and Workshop on Insight into the World of Indigenous Fermented Foods for Technology Development and Food Safety; Bangkok, pp.1 – 10. Greenwood, C.T. and Munro, D.N. (1979). Carbohydrates. R.J. Priestley, ed. Effects of Heat on Food stuffs. London: Applied Science Publ. Ltd. Gunawan, S., Widjaja, T., Zullaikah, S., Ernawati, L., Istianah, N., Aparamarta, H.W. dan Prasetyoko, D. (2015). Effect of Fermenting Cassava with Lactobacillus plantarum, Saccharomyces cerevisiae, and Rhizopus oryzae on the Chemical Composition of Their Flour. Int. Food Res. J. 22, 1280-1287. Hahn, S.K., (1992). An Overview of Traditional Processing and Utilizatin of Cassava in Africa. In Hahn, S.K., Reynolds, L. and Egbunike, G.N. (Eds). Cassava as Live Stock Feed in Africa, p. 16-27. Ibadan: International Institute for Tropical Agriculture (IITA). Hee-Young. (2005). Effects of Ozonation and Addition of Amino Acids On Properties of Rice Starches. A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy. Hidayat, N., Padaga, M.C., and Suhartini, S. (2006). Mikrobiologi Industri. Andi, Yogyakarta. International Starch Institute. (2014). Gari. http://www.starch.dk/isi/ starch/gari.asp. Jayasuriya, C. (2015). Singkong Obat Ajaib untuk Kanker. http://akinarishop.com/berita/ detail/singkong-obat-ajaib-untuk-kanker-4774.html. Kobawila, S.C., Louembe, D., Keleke, S., Hounhouigan, J., and Gamba, C., (2005). Reduction of The Cyanide Content During Fermentation of Cassava Roots and Leaves to Produce Bikedi and Ntoba Mbodi, Two Food Products from Congo. Afr. J. Biotechnol. 4, 689-696. Lingga. P., (1990). Bertanam Ubi – Ubian. Jakarta: Penebar Swadaya. Miyazaki, M. R., Hung, P. V., Maeda, T. and Morita, N. (2006), Recent advances in application of modified starches for bread making. Trends Food Sci. Tech., 17, 591-599. Myatt, L., (2002). Role of placenta in preeclampsia. Endocrine 19, 103-111. Mokemiabeka, S., Dhellot, J., Kobawila, S.C., Diakabana, P., Ntietie-Loukombo, R.N., Nyanga-Koumou, A.G., and Louembe, D. (2011). Softening and Mineral Content of Cassava (Manihot esculenta Crantz) Leaves During the Fermentation to Produce Ntoba mbodi. Adv. J. Food Sci. Technol. 3, 418-423. Montagnac, J.A. and Davis, C.R. (2009). Nutritional Value of Cassava for Use as a Staple Food and Recent Advances for Improvement. Compr. Rev. Food, vol. 8. Moshi, A. P. (2015). Production of Bioethanol from Wild Cassava Manihot glaziovii through Various Combinations of Hydrolysis and Fermentation in Stirred Tank Bioreactors. Sweden. British Journal. 5. Naliaka, T.K. (2015). Chikwangue. https://commons.wikimedia.org/wiki/ File:Chikwangue.


294


Nhassico D., Muquingue H., Cliff J., Cumbana A., Bradbury J.H. (2008) Rising African cassava production, diseases due to high cyanide intake and control measures. J. Sci. Food Agr, 88, 2043–2049. Nuwamanya, E., Baguma, Y., Kawuki, R.S. and Rubaihayo, P.R. (2011). Quantification of Starch Physicochemical Characteristics in A Cassava Segregating Population. Afr. Crop Sci. J. 16, 191-202. Oboh, G. and Akindahunsi, A.A. (2003). Biochemical changes in cassava products (flour and gari) subjected to Saccharomyces cereviseae solid media fermentation. Food Chem. 82, 599-602. Oboh, G., Akindahunsi, A.A. and Osodhi, A.A. (2002). Nutrient and Antinutrient content of Aspergillus niger fermented cassava product (flour and gari). Journal of Food Composition and Analysis 15: 617-622. Oduah, N.O., Adepoju, P.A., Longe, O., Elemo, G.N. and Oke, O.V. (2015). Effects Of Fermentation On The Quality And Composition Of Cassava Mash(Gari). International Journal of Food Nutrition and Safety. 6, 30-41 Onwueme, I.C. (1978). The Tropical Tuber Crops: Yams, Cassava, Sweet Potato and Cocoyams. Wiley, NewYork, ISBN: 9780471996071, pp: 210. Oppong-Apane, K., (2013). Cassava as Animal Feed in Ghana: Past, Present and Future. Accra: Food and Agriculture Organization of the United Nations. Ogunnaike, A. M., Adepoju, P. A., Longe, A. O., Elemo, G. N., Oke, O.V. (2015). Effets of Submerged and Anaerobic Fermentation on Cassava Flour (Lafun). Afr J Biotechnol. 14, 961-970. Ojo, A., Abiodun, O.A., Odedeji, J.O., and Akintoyese, O.A. (2014). Effects of Drying Methods on Proximate and Physico-chemical Properties of Fufu Flour Fortified with Soybean. Br. J. Appl. Sci. Technol. 4, 2079-2089. Padonou S.W, Hounhouigan J.D, Nago M.C (2009). Physical, chemical and microbiological characteristics of lafun produced in Benin. Afr J Biotechnol. 8, 3320-3325. Phrueksawan, P., Kulpreecha, S., Sooksai, S. and Thongchul, N. (2012). Direct fermentation of L(+)-lactic acid from cassava pulp by solid state culture of Rhizopus oryzae. Bioprocess Biosyst. Eng. 35, 1429-1436. Quintero, J. E., Alejandro A. C., Carlos M. G, Rigoberto R. E., Ana M.T. L. (2012). Lactic acid production via cassava-flourhydrolysate fermentation. Vitae, Revista De La Facultad De Quimica Farmaceutica, 19: 287-293. Rauf, W., (2015). List of Products by Manufacturer Mac. Phillips Foods. http://www.indopak.se/28_ Richana, N., (2012). Budidaya Singkong. Bandung: ITB. Saleh, Z. (2015). Hukum Tape. http://tarbijahislamijah.com/hukum-tape-tapai. Shiu, P., Gunawan, S., Hsieh, W.H., Kasim, N.S., Ju, Y.H. (2010). Biodiesel production from rice bran by a two-step in-situ proces. Bioresour. Technol. 101, 984-989. Suprihatin. 2010. Teknologi Fermentasi. Surabaya: UNESA Press. Sulistyo, J and Nakahara, K. (2014). Physicochemical properties of modified cassava starch prepared by application of mixed microbial starter. Int. j. res. agric. food, 2, 1-8. ISSN 2311 -2476. Silva, A.D.S., Mota, T.A., Fernandes, M.G., and Kassab, S.O. Spatial distribution of Bemisia tuberculata (Hemiptera: Aleyrodidae) on cassava crop in Brazil. Rev. Colomb. Entomol. 39, 93-196.



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Takizawa, F. F., Silva, G. O., Konkel, F. E., Demiate, I. M. (2004) Characterization of tropical starches modified with potassium permanganate and lactic acid. Braz. arch. biol. technol., 47, 921-931. Tortora, G., Funke, B.R., and Case, C.L. (2010). Microbiology: An Introduction, 10th edition. San Francisco: Pearson Education Inc., 141-147. USDA National Nutrient Database for Standard Reference. (2014). Proximate Nutrient Composition of Cassava. http://www.nal.usda.gov./fnic/food comp/search/. Wang, L., Feng, Z., Wang, X., Wang, X., Zhang, X. (2010). DEGseq: an R package for identifying differentially expressed genes from RNA-seq data. Bioinformatics 26, 136– 138. Westby, A., Choo, B.K. (1994). Cyanogen Reduction during Lactic Fermentation of Cassava. Acta Hortic, 375, 15 - 209.





Chapter 15

RECENT ADVANCES IN THE DEVELOPMENT OF BIODEGRADABLE FILMS AND FOAMS FROM CASSAVA STARCH Giordana Suárez1 and Tomy J. Gutiérrez2,* 1

School of Chemistry, Faculty of Sciences, Central University of Venezuela, Caracas, Venezuela 2 Composite Materials Group, Institute of Materials Science and Technology (INTEMA) (CONICET-UNMdP), Faculty of Engineering, National University of Mar del Plata and National Research Council (CONICET), Mar del Plata, Argentina

ABSTRACT Currently eco-friendly polymeric materials are made from different biopolymers. In this sense, special attention has brought the use of starch at industrial level, since can be processed as conventional polymers. In the same way, one of the starches most used for developing biodegradable films and foams for use as packing material has been cassava (Manihot esculenta) starch, due to its high production and performance, which makes it be a promising material for replacement of polymers obtained from the petrochemical industry. At regard, in this chapter will be reviewed and discussed recent advances related to the development of biodegradable films and foams made from cassava starch.

Keywords: cassava, eco-materials, films, foams, packaging, starch, thermoplastic materials

*

Corresponding Author address: Institute of Materials Science and Technology, Faculty of Engineering, National University of Mar del Plata and National Research Council (CONICET), PO Box B7608FLC, Solís 7575, Mar del Plata, Argentina. Tel.: +54 223 481 6600 int 321; fax: +54 223 481 0046. E-mail address: [email protected]; [email protected].


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Giordana Suárez and Tomy J. Gutiérrez

INTRODUCTION The synthetic polymers have replaced metals, glasses, ceramics and wood in many applications, chiefly in the area of packaging. The main commodity plastics, the so-called “big five”, which are polyethylene (PE), poly(propylene) (PP), polystyrene (PS), poly(vinyl chloride) (PVC) and poly(ethylene terephthalate) (PET) have revolutionized the packaging industry in a variety of forms such as films, flexible bags, rigid containers and foams (Soykeabkaew et al. 2015). In this context, our dependence on plastic in our daily life is very high, since we use almost 100 million tons annually, which has preoccupied the world population, since these materials are highly polluting and contribute to global overheating of planet earth (Iriani et al. 2015). As an alternative have emerged mainly biodegradable materials from starch, and specifically cassava starch has had much attention for their extraordinary properties in this regard. Therefore, in the present chapter will be reviewed and discussed recent advances related to the development of biodegradable films and foams made from cassava starch.

1. CASSAVA Cassava (Manihot esculenta) belongs to Euphorbiaceae family and responds to various names such as cassava, tapioca, mandioca or yuca (Montaldo 1991). Its cultivation is done with the purpose of being a food plant or for industrial purposes, being noted its use increasingly in the industriy. Due to its high starch content, cassava is used, along with corn, as the main sources of raw material for starch extraction (Thomas and Atwell 1999). There are two types of cassava: bitter cassava and sweet cassava. The first, more developed, rich in starch and with a higher content of linamarin (cyanogenic glucoside), whereas the second is generally for direct consumption. An alternative to minimize losses in this area is starch production, which exhibits characteristics of particular interest in industrial applications, due to its high purity, neutral taste, easy swelling and solubilization, and considerable development of viscosity. Cassava is considered as the third most significant food source for those who live in tropical areas. It is also the fifth most produced starch crop around the worlds (Edhirej et al. 2015). It is a type of plant which has different purposes of use. It is used to produce various foods, biofibers, bio-composites and bio-polymers. Besides, now is used as renewable energy source. The intention is to focus on the importance of cassava as biodegradable material to various industrial applications such as the food production, cassava films and foams, food packaging and the incorporation of organic or inorganic natural nanofillers in polymeric matrices based on cassava starch. On the other hand, studies carried out have allowed to evaluate the composition of cassava roots, yielding values of 70.25% moisture, 13.13% sugar, 1.12% protein, 0.14% fat, 1.11% fiber and 0.54% ash. It is also considered that bitter varieties have on average 30% of starch (Grace 1987). Due to high starch content in their roots, the bitter varieties are grown for industrial purposes.


Recent Advances in the Development of Biodegradable Films …

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2. CASSAVA STARCH Among the most studied biopolymers is found cassava starch, which has the advantages of coming from renewable sources and being biodegradable, inexpensive (US$ 0.25-0.60/ kg), and widely available (da Silva et al. 2013). In this sense, cassava starch is extracted from the plant roots by various processes that are described in Figure 1. In the case of cassava starch, have been reported moisture content values ranging from 8.2 to 14% (Whistler and Paschal 1967; Wurzburg 1972; Matos 1996a). Whistler and Paschal (1967), have indicated that moisture can vary up to values of 15% depending on storage conditions. However, values greater than 18% bring problems mainly due to growth of molds and other microorganisms, as well as avoiding the flow of material due to caking of the particles (Radley 1976). Matos (1996b) and Matos and Pérez (2003) indicated that chemical analysis of the cassava starch revealed a high purity (~ 98%), for both research works. Pérez (1994), reported a total starch content of 99.5%. The fat presented a value of 0.17%, ash 0.11%, crude protein 0.75% and crude fiber 0.49%. Similar results were also reported by Gutiérrez et al. (2014).

Figure 1. Flow chart for cassava starch production (Pérez et al. 1993).


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3. BIODEGRADABLE FILMS FROM CASSAVA STARCH Starch is one of polysaccharides used to obtain biodegradable films because of its ability to form a continuous matrix, its low permeability to oxygen (Liu 2005; Dole et al. 2004), and compared to other non-starch films, its lower cost. However, like other hydrocolloids, when compared to plastic polymers, starch films exhibit several drawbacks, such as their hydrophilic character and poor mechanical properties. Nonetheless, films based on starch are transparent, odorless, tasteless, and colorless (Mali et al. 2004, Jiménez et al. 2012). Biodegradable starch films can be obtained from the native starch or its components, amylose and amylopectin, by two main techniques: solution casting and subsequent drying (wet method) and thermoplastic processing (dry method) (Paes et al. 2008). Native, modified or pre-gelatinized starches have also been used to obtain starch films (Pagella et al. 2002; López et al. 2008). As mentioned previously, starch films can be formed from a film-forming dispersion, or an emulsion, which contains a high percentage of water. Otherwise, starch films may be obtained by using a dry process (thermoplastic or thermal processing) in which the water content is lower when compared to the wet process. A dry process can be used with those raw materials which present thermoplastic properties; this means that they become soft (melted or rubbery) at a temperature lower than decomposition temperature and so, they can be molded into a determined shape when submitted to a thermal/mechanical process. Although starch does not present this characteristic in its native state, it is capable of becoming a thermoplastic material if it is treated correctly. According to Carvalho (2008), thermoplastic starch (TPS) is generally produced by processing a starch-plasticizer(s) mixture in an extruder at temperatures between 140 and 160 °C at high pressure and high shear. Additionally, batch mixers can also be used, operating in conditions similar to those of the extrusion process. The result of the process, in which starch granules are disrupted and mixed with one or a mixture of plasticizers is the TPS. The presence of plasticizers (not only water) is necessary in order to obtain a rubbery material, without brittleness, when equilibrated at ambient relative humidity (Forssell et al. 1997). In order to obtain starch-based films, an essential requirement which must be considered is that, if native starch is used, the granules have to be disrupted previously through a gelatinization process in an excess of water media (> 90% w/w, Carvalho 2008), where they undergo an irreversible order–disorder transition, or destructuration. Starch gelatinization is a process in which granules swell, depending on the available water, provoking the breakage of the amylopectin matrix and releasing the amylose. In other words, it can be considered as a first step, in which the solvent diffuses through the starch granules and a second, in which the melting of the starch crystallites takes place (Carvalho 2008). Although the gelatinization process seems to be simple, it is a very complex process. According to Ratnayake and Jackson (2007), the gelatinization process initiates at low temperatures and continues until that the granules are completely disrupted. These authors studied seven types of starch by scanning electron microscopy and observed differences in the granule structure when were treated at different temperatures. Furthermore, they summarized the gelatinization as a threestage process during which different structural events take place:



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1. The water absorption by starch granules promotes an increase in starch polymer mobility in amorphous regions. 2. Starch polymers in the amorphous regions rearrange often forming new intermolecular interactions. 3. With increasing hydrothermal effects, the polymers become more mobile and lose their intermolecular interactions and overall granular structure. In order to ensure sustainability in the plastics sector it is essential to develop new biopolymers with new routes and/or synthesis processes that enable highly efficient procurement implementation within the sector. It is also necessary to reduce the cost of biopolymers as well as improve their mechanical and thermal properties. In this regard has been implemented as synthesis route the reactive extrusion. Reactive extrusion (REX) is a process that combines the mass and heat transportation operations with simultaneous chemical reactions taking place inside the extruder for the purpose of modifying the properties of existing polymers or for producing new ones. REX is increasingly becoming a powerful technique to develop and fabricate a variety of novel polymeric materials in a highly efficient and flexible way. This combination of chemical reactions and transport phenomena in an extruder provides a large opportunity window for polymeric prototyping (Tzoganakis et al. 1989).

3.1. Properties of Cassava Film Alves el at. (2007) have observed and studied the properties of cassava films and some important results were obtained. It was found that the elongation, Young’s modulus and tensile strength decreased when the glycerol concentration was increased. On the other hand, water solubility, moisture content and water vapor permeability of the cassava film increased with the escalating glycerol concentration. Therefore, the glycerol content affected both the mechanical and water barrier properties.

3.1.1. Physicochemical Properties of Cassava Films 3.1.1.1. Moisture Content Table 1 shows the moisture content (MC) of the cassava starch biodegradable films. The moisture content was found to be high when the glycerol content was high (45 wt%) and low when the amount of glycerol was low (30 wt%). The values of moisture content for the films ranged in between 11.8% and 41.1% (Alves el at. 2007). 3.1.1.2. Water Solubility Table 1 shows the water solubility (WS) of cassava films. Increasing the amount of glycerol in the film led to increased solubility of the cassava in water. The values of solubility ranged in between 23.0% and 32.1% (Alves el at. 2007). 3.1.1.3. Water Vapour Permeability Table 1 lays out water vapour permeability of the cassava films. The water vapour permeability of the cassava films increased with the enhanced amount of glycerol in the film.


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The values of water vapor permeability ranged in between 3.28x10-10 g/m.Pa and 4.47x10-10 g/m.Pa (Alves el at. 2007).

3.1.2. Mechanical Properties of Cassava Films As has been mentioned earlier, presence of glycerol has a direct influence on the percent elongation, Young’s modulus and tensile strength of the cassava films. Increasing the amount of glycerol resulted in the decrement of Young’s modulus (E) and tensile strength (σ) (Bangyekan et al. 2006). This is because of certain alterations on the structure of starch network upon addition of glycerol. The network became under stress and also less dense when glycerol was amalgamated. Therefore, the flexibility of film improved because of the ease in movement of polymer chains. The percent elongation (ε) of the films also decreases with the increase in glycerol content. Due to this property of the films, the starch films became more ductile i.e., easily breakable instead of becoming more brittle. These three properties have been shown in the table as a function of the glycerol contained (Silva et al. 2008). 3.1.3. Other Properties of Cassava Films Gutiérrez et al. (2015a,b) evaluated two starches (cassava and cush-cush yam) with different amylose contents for edible films forming plasticized with glycerol, determining that a more open and compact structure it is associated with the greater hydrogen bonding interaction between the amylose and the glycerol, thus allowing obtain films with greater elongation. Therefore, open and compact structures are related to improved hydrogen bonding interactions between glycerol and starch. Moreover, due to hydrophilic nature of the starch different alternatives have been used to overcome this, including: starch modification, addition of natural fillers and catalysts, blends with other polymers, plasticizer rate variation, photochemical modifications, among others (Gutiérrez and González 2016). It is also worth noting that the starch-based products has another problem and is the problem of aging, i.e., their properties are modified during storage. Since alternatives to solve the problems inherent in the films based on cassava starch are equal to options to solve the problems of cassava starch foams, therefore, in the next section will be explained. Table 1. Moisture contents, water solubility, water vapor, and mechanical properties of cassava films, as a function of glycerol content Glycerol (%) 30 35 40 45

WSP (x 10-10 g/m.s.Pa) 3.28 4.22 4.39 3.39

WS (%)

MC (%)

σ(MPa)

ε (%)

E (MPa)

23.0 26.0 29.2 32.1

11.8 22.2 24.8 41.1

2.4 2.1 1.4 1.2

49.4 41.9 28.8 26.8

46.3 32.2 14.7 14.0



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4. BIODEGRADABLE FOAMS FROM CASSAVA STARCH Polystyrene foam is most common in single-use plastic packaging due to its high strength, low density, good thermal insulation property and low cost (Kaisangsri et al. 2012). However, polystyrene foams may require several hundred years to degrade and can cause serious environmental pollution (Kaisangsri et al. 2014). In this sense, increasing environmental concerns on the global waste problem have motivated the global interests in producing environmentally friendly products from renewable resources (Soykeabkaew et al. 2015). Biodegradable packaging produced from renewable sources is an alternative to conventional plastic packaging. Agromaterials such as cassava starch is a very promising raw material to reduce our dependence on polystyrene (Iriani et al. 2015). The starch-based foams have emerged as polystyrene replacements, and currently the the aim in this field is to improve the drawbacks of the starch itself, since are well known these problems, i.e., poor mechanical properties, high hydrophilicity and changes under temperature conditions (Shogren et al. 2002; Mello and Mali 2014; Palma-Rodríguez et al. 2016). To overcome these limitations, many research groups have tried to improve the properties of starch foams by using modified starch derivatives, e.g., starch acetate, cationic starch, pregelatinized starch and cross-linked starch (Pornsuksomboon et al. 2014). The results have suggested that differences in botanic source, granule dimension, moisture, protein, fiber content, as well as the amylose/amylopectin ratio influence on the resulting foams (Soykeabkaew et al. 2015). In addition, Shogren et al. (2002) has shown that foams made from chemically modified starch have shorter baking times, are lighter and show a higher elongation at break than unmodified starch. Guan and Hanna (2006), have indicated that the degree of cross-linking and degree of substitution may affect the baking time, the density, the mechanical properties, and water absorptivity of starch foams. Kaewtatip et al. (2014) have claimed that the thermal stability and morphology of starch foams depends on the type of the substituent in the starch derivative. Pornsuksomboon et al. (2014) have made starch foams from native cassava starch/crosslinked starch blends, which were prepared by baking in a hot mold. The native cassava starch/cross-linked starch ratio was varied in the series of 100/0, 80/20, 60/40, 50/50, 40/60, 20/80, and 0/100. The authors investigated the effect of the native cassava starch/cross-linked starch ratio on the properties of foams including density, morphology, water adsorption, impact strength and thermal stability. The mixture of cross-linked starch resulted in a higher density of the foams. The impact strength of the blend foams were between 232 and 268 J/m2. The water adsorption for the modified starch foams (7.3%) and the blend foams (11-12%) was lower than for the native cassava starch foam (13.9%). Also, higher density values (~0.15 g/cm3) have been reported for potato starch foams than those made from cassava starch (~0.12 g/cm3) (Soykeabkaew et al. 2015). Similarly, in order to enhance water resistance and strength of the foams, various biodegradable polymers, for example, poly(lactic acid) (PLA), poly(ε-caprolactone) (PCL), poly(vinyl alcohol) (PVA), chitosan, poly(hydroxyester ether) (PHEE), poly(hydroxybutyrate-co-valerate) (PHBV), poly(butylenes-succinate) (PBSA), butanediolterephthalate-adipate terpolymer (PBAT), cellulose acetate (CA), poly(ester amide) (PEA) have been blended with starches (Soykeabkaew et al. 2015). For example, the water resistance of baked starch-based foams was improved by the addition of hydrophobic


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materials such as monostearyl citrate, latex and PCL (Shey et al. 2006). Shey et al. (2006) found that latex could be added to the batter of baked starch foams to increase their flexibility and moisture resistance. Iriani et al. (2015), have also displayed that the addition of PVA up to 30% can increase starch-baked foam compressibility and tensile strength The best formulation to produce starch-baked foam is cassava starch: corn hominy: PVA = (75:25):30%. Likewise, to improve the mechanical properties of starch foams have been added various fillers such as fibers, clay, proteins, wax, ethylene-vinyl acetate copolymer and calcium carbonate (Pornsuksomboon et al. 2014; Soykeabkaew et al. 2015). Additionally, the nanoscale fillers have opened the new windows to the development of starch-based foams. Due to the nano-sized effect, various properties of the foams have shown to be effectively improved at low filler content (Mansourighasri et al. 2012; Matsuda et al. 2013). It is very well observed that a wide range of the starch-based foam properties can be achieved and tuned by the selection of appropriate processing technique as well as the set of input ingredients, the types of starches, blend sand additives/fillers. The success and continuity in developing of starch-based foams will make possible to many more of their new applications (Soykeabkaew et al. 2015). However, the hydrophilic characteristics of the starch foam can cause incompatibility with some hydrophobic fillers and they are also prone to aggregate during foam production process (Pornsuksomboon et al. 2014). Kaisangsri et al. (2014) reported that the increased kraft fiber content (5-15 wt%) in cassava starch foam trays caused their flexural and compressive strengths to increase. Soykeabkaew et al. (2004) found that addition of 10% jute or flax fibers to the cassava starchbased foams significantly improved the flexural strength due to the cross-link reaction between starch and fibers. On the contrary, the addition of some kraft fibers into starch foam results in high density, and some types of kraft fiber produce a dark color. The density of starch-based foam blended with cassava, wheat, jute, flex and softwood fiber was 0.1-0.3 g/cm3 (Glenn et al. 2001; Soykeabkaew et al. 2004; Carr et al. 2006). Kaisangsri et al. (2012) conducted a study to improve quality of cassava starch-based foam for application in fresh cut fruits. The kraft fiber at 0, 10, 20, 30 and 40% (w/w of starch) and chitosan at 0, 2, 4 and 6% was mixed with cassava starch. Hot mold baking was used to develop the cassava starch-based foam by using a baking machine controlled temperature at 250 oC for 5 min. Results showed that foam produced from cassava starch, 30% kraft fiber (w/w of starch) and 4% chitosan had properties similar to polystyrene foam. Tensile strength and elongation of starch-based foam were 944.40 kPa and 2.43%, respectively, but the water absorption index and water solubility index were greater than the polystyrene foam. Vercelheze et al. (2012) found that the addition of sugarcane bagasse and clay (NaMMT) decreased the density and stress at break and increased the strain at break values of the starch foams. Fiber and Na-MMT acted as reinforcing fillers that improved the foaming ability of the starch pastes, resulting in more expandable materials. Another foam made from starch, cellulose and protein isolates from sunflower produced a foam with a density ranging from 0.45 to 0.58 g/cm3, while starch, cellulose fiber and CaCO3 produced foam with a density 0.63 to 1.3g/cm3 (Schmidt 2006). Vercelheze et al. (2013), in another study found that the addition of fibers and Na-MMT resulted in less dense and less rigid trays compared to control samples (only starch).



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Later on, Mello and Mali (2014) also reported that addition of 5-15 wt% malt bagasse (particles < 0.3 mm) in cassava foams resulted in high tensile strength of approximately 13 MPa, thicknesses ranged from 2.16 to 2.24 mm and densities ranged from 0.415 to 0.450 g/cm3. Each tray produced in this study had a good appearance, adequate expansion, and a homogeneous distribution of malt bagasse in the polymeric matrix. The addition of the lignocellulosic material at concentrations up to 15% (w/w) decreased the initial moisture adsorption rate of the trays. According to authors the main application of these trays is for dry food packaging that have short shelf-life. Kaisangsri et al. (2014) demonstrated that the addition of kraft, zein, and gluten could improve flexural and compressive strength of the cassava starch foam trays. Moreover, the water absorption and water solubility index of blended cassava starch foams with zein and gluten proteins were low. Although adding palm oil into cassava starch foams increased the water resistance, their flexural and compressive strength decreased. These findings demonstrate that blended cassava starch foam trays with kraft, gluten and/or zein could be used as an alternative to polystyrene foam trays for oily and less moist foods. The starch foam trays should further improve and develop their expansion, water resistance and their possible application to moist foods. Moreover, water is also an important component because it acts as the blowing agent in the expansion process. Starch pastes also must have certain rheological characteristics such that the foam does not collapse during water evaporation. Pastes with low water content were very viscous and result in less expandable and higher density foams, and the presence of fibers and other solids in the formulations increase the viscosity of the mixture, which decreases its foaming ability (Cinelli et al. 2006). Other research indicated that water addition during extrusion process may less en the magnitude of radial expansion (Yu et al. 2006, Ma et al. 2008, Sarazin et al. 2008) and volumetric expansion (Jawaid and Klali 2011). One characteristic of foam property is density, and lower density is better for packaging. Foam density is affected by starch, fiber, synthetic polymer and interactions between the materials (Mali et al. 2010). The addition of fiber tends to limit expansion ability and result in stiff materials, which do not support air cell growth in their foams. It was also reported that a reduction in foam density was achieved with the addition of corn fiber (Glenn et al. 2001, Cinelli et al. 2006). On the other hand, the starch-based foams can be produced by many techniques such as hot-press technology, extrusion processes and baking starch/water batters in heated closed molds (Shogren et al. 2002; Iriani et al. 2015), but essentially the creation of starch-based foam can be divided into two main steps: starch gelatinization and water evaporation from batter. In this sense, the mixture is expanded and forms a foam dewatered to a moisture content of 2-4% (Soykeabkaew et al. 2004; Kaisangsri et al. 2012; Vercelheze et al. 2012). Each technique has its own processing parameters which affect the product properties including shapes, cellular structures, density and mechanical properties. For example, increasing barrel temperature and screw speed usually increases the number of cells, and as a result, generally increases expansion ratio of the extruded foams leading to a decrease in foam density (Soykeabkaew et al. 2015). However, the starch-foam products can be designed to suit a particular application via appropriate processing systems. Usually, extrusion processing system produces the foam with large cell size and that leads to the production of low density products. This can be useful for the application where the weight is the high priority such as packaging for transportation (Soykeabkaew et al. 2015). Researchers have produced starch


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puff, this kind of product is known also as plate expanded by extrusion, gelatinized starch puff or baking with water.The products are formed in the extruder by the swelling and expansion of starch through the action of high temperature and water vapor to form starch foam (Poovarodom and Praditduang 1999). Clean Green Company in Minneapolis, MN, USA, has produced “starch foam” by extrusion of wheat starch and polyvinyl alcohol. “Eco-Foam”, a product of National Starch, using waxy corn as raw material. In European countries, the baking technology is also at a commercial scale. Packaging products, such as fast food utensils, are available in the market using both cereal and potato starches. The marketing of biodegradable packaging products are supported in the EU. Cassava starch has been successfully expanded under extrusion conditions. Due to its low bulk density, a little modification is needed so that its moisture content is increased. Twin screw extrusion Figure 2 is recommended for direct expansion of cassava starches. Cassava starch can also be used as the raw material for plate expanded or baking products. Cassava starch can be expanded in moulds, for 1-3 min. at 200-240 oC, to form into package utensils such as bowls. About 10% additives, including calcium carbonate, agar, or emulsifier is needed to improve the properties (Parra et al. 2004). In applications that required the well-molded shape such as disposal containers, baking or compression process may be well suited as the foam is expanded within a well-closed mold. Microwaved foams allow thick cell walls which can be suitable for the application where strength and stiffness are essential. Whereas, the applications which required micro-scale and uniform cells with interconnectivity such as scaffold or drug delivery system, the freeze drying and solvent exchange processes should be more suitable. Lastly, a novel supercritical fluid extrusion technology seems to be more versatile and controllable, thus, a wide range of foam structures with desired properties can be better designed for several uses.

Figure 2. Extrusion of cassava foam (Parra et al. 2004).

CONCLUSION AND OUTLOOKS Films based on cassava starch have been widely studied for food packaging applications. Nonetheless, the same has not happened with foams based on cassava starch. These materials are promising as a replacement for plastic materials obtained from the petrochemical industry, which would allow the production of “green” materials. However, several well-known disadvantages are produced during the storage of these thermoplastic materials. For this



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reason, its study this on top of researches in the field of polymers. To improve the mechanical and physicochemical properties of these materials have been added various natural fillers within these native or modified matrices with different types of plasticizers. Even cassava starch mixtures with other biopolymers have been made to overcome the hydrophilic nature of starch. However, these investigations are still booming because of its importance. In the future early, a large part of plastic materials known to date will be made from cassava or corn starch, since its high production and yields that make attractive in polymer and food industries. Additionally, due to characteristics of the cassava starch, this can be applied under the conventional-polymers processing technology, i.e., extrusion. This together with the reactivity that present the starch, gives rise to the possibility to reactive reactions using the extruder as a chemical reactor. Therefore, this will be the future trends in the development of polymeric materials based on cassava starch.

ACKNOWLEDGMENTS The authors would like to thank Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Postdoctoral fellowship internal PDTS-Resolution 2417), Universidad Nacional de Mar del Plata (UNMdP) for the financial support and to Dr. Mirian CarmonaRodríguez.

REFERENCES Alves, V.D., S. Mali, A. Beléia, M.V.E. Grossmann. 2007. “Effect of glycerol and amylose enrichment on cassava starch film properties”. Journal of Food Engineering, 78(3): 941946. Bangyekan, C., D. Aht-Ong, K. Srikulkit. 2006. “Preparation and properties evaluation of chitosan-coated cassava starch films”. Carbohydrate Polymers, 63(1): 61-71. Carr, L.G., D.F. Parra, P. Ponce, A.B. Lugao, P.M. Buchler. 2006. “Influence of fibers on the mechanical properties of cassava starch foams”. Journal of Polymers and the Environment, 14(2): 179-183. Carvalho, A.J. 2008. “Starch: major sources, properties and applications as thermoplastic materials”. In: Monomers, polymers and composites from renewable resources. M.N. Belgacem & A. Gandini (Eds.). Elsevier, Amsterdam. Pp. 321-342. Cinelli, P., E. Chiellini, J.W. Lawton, S.H. Imam. 2006. “Foamed articles based on potato starch, corn fibers and poly (vinyl alcohol)”. Polymer Degradation and Stability, 91(5): 1147-1155. da Silva, A., L.M. Nievola, C.A. Tischer, S. Mali, P. Faria‐Tischer. 2013. “Cassava starch‐based foams reinforced with bacterial cellulose”. Journal of Applied Polymer Science 130(5): 3043-3049. Dole, P., C. Joly, E. Espuche, I. Alric, N. Gontard. 2004. “Gas transport properties of starch based films”. Carbohydrate Polymers, 58(3): 335-343. Edhirej, A., S.M. Sapuan, M. Jawaid, N.I. Zahari. 2015. “Cassava: Its polymer, fiber, composite, and application”. Polymer Composites. 1-16.


308


Forssell, P.M., J.M. Mikkilä, G.K. Moates, R. Parker. 1997. “Phase and glass transition behaviour of concentrated barley starch-glycerol-water mixtures, a model for thermoplastic starch”. Carbohydrate Polymers, 34(4): 275-282. Glenn, G.M., W.J. Orts, G.A.R. Nobes. 2001. “Starch, fiber and CaCO3 effects on the physical properties of foams made by a baking process”. Industrial Crops and Products, 14(3): 201-212. Glenn, G.M., W.J. Orts. 2001. “Properties of starch-based foam formed by compression/explosion processing”. Industrial Crops and Products, 13(2): 135-143. Grace, M.R. 1987. Cassava Processing. Food and Agriculture Organization (FAO). pp. 55-61. Roma. Guan, J., M.A. Hanna. 2006. “Selected morphological and functional properties of extruded acetylated starch-cellulose foams”. Bioresource technology, 97(14): 1716-1726. Gutiérrez, T.J., E. Pérez, R. Guzmán, M.S. Tapia, L. Famá. 2014. “Physicochemical and functional properties of native and modified by crosslinking, dark-cush-cush yam (dioscorea trifida) and cassava (manihot esculenta) starch”. Journal of Polymer and Biopolymer Physics Chemistry, 2(1): 1-5. Gutiérrez, T.J., G. González. (2016). Effects of exposure to pulsed light on surface and structural properties of edible films made from cassava and taro starch. Food and Bioprocess Technology. 9(8): Gutiérrez, T.J., M.S. Tapia, E. Pérez, L. Famá. 2015. “Structural and mechanical properties of edible films made from native and modified cush-cush yam and cassava starch”. Food Hydrocolloids 45: 211-217. Gutiérrez, T.J., N.J. Morales, E. Pérez, M.S. Tapia, L. Famá. 2015. “Physico-chemical properties of edible films derived from native and phosphated cush-cush yam and cassava starches”. Food Packaging and Shelf Life 3: 1-8. Iriani, E.S., T.T. Irawadi, T.C. Sunarti, N. Richana, I. Yuliasih. 2015. “Effect of corn hominy and polyvinyl alcohol on mechanical properties of cassava starch-baked foam”. PolymerPlastics Technology and Engineering 54(3): 282-289. Jawaid, M.H.P.S., H.A. Khalil. 2011. “Cellulosic/synthetic fibre reinforced polymer hybrid composites: A review”. Carbohydrate Polymers, 86(1): 1-18. Jiménez, A., M.J. Fabra, P. Talens, A. Chiralt. 2012. “Effect of re-crystallization on tensile, optical and water vapour barrier properties of corn starch films containing fatty acids”. Food Hydrocolloids, 26(1): 302-310. Kaewtatip, K., M. Poungroi, B. Holló, K.M. Szécsényi. 2014. “Effects of starch types on the properties of baked starch foams”. Journal of Thermal Analysis and Calorimetry, 115(1): 833-840. Kaisangsri, N., O. Kerdchoechuen, N. Laohakunjit. 2012. “Biodegradable foam tray from cassava starch blended with natural fiber and chitosan”. Industrial Crops and Products 37(1): 542-546. Kaisangsri, N., O. Kerdchoechuen, N. Laohakunjit. 2014. “Characterization of cassava starch based foam blended with plant proteins, kraft fiber, and palm oil”. Carbohydrate Polymers 110: 70-77. Liu, Z. 2005. “Edible films and coatings from starch”. In: Innovations in food packaging. Han, J.H. (Ed.). London: Elsevier Academic Press. Pp. 318-332. López, O.V., M.A. García, N.E. Zaritzky. 2008. “Film forming capacity of chemically modified corn starches”. Carbohydrate Polymers, 73(4): 573-581.



309

Ma, X., P.R. Chang, J. Yu. 2008. “Properties of biodegradable thermoplastic pea starch/carboxymethyl cellulose and pea starch/microcrystalline cellulose composites”. Carbohydrate Polymers, 72(3): 369-375. Mali, S., F. Debiagi, M.V. Grossmann, F. Yamashita. 2010. “Starch, sugarcane bagasse fibre, and polyvinyl alcohol effects on extruded foam properties: A mixture design approach”. Industrial Crops and Products, 32(3): 353-359. Mali, S., M.V.E. Grossmann, M.A. Garcıá , M.N. Martino, N.E. Zaritzky. 2004. “Barrier, mechanical and optical properties of plasticized yam starch films”. Carbohydrate Polymers, 56(2): 129-135. Mansourighasri, A., N. Muhamad, A.B. Sulong. 2012. “Processing titanium foams using tapioca starch as a space holder”. Journal of Materials Processing Technology 212(1): 83-89. Matos, M.E. 1996a. Aprovechamiento integral y uso industrial de la yuca (Manihot esculenta Crantz). Seminario Especial de Grado. Facultad de Ciencias. Universidad Central de Venezuela. Caracas, Venezuela. Matos, M.E. 1996b. Modificación por métodos químicos de fosfatación, acetilación y doble derivación de almidón de yuca. Tesis de Maestría en Ciencias y Tecnología de Alimentos. Facultad de Ciencias. Universidad Central de Venezuela. Caracas, Venezuela. Matos, M.E., E. Pérez. 2003. “Characterization of native and modified cassava starches by scanning electron microscopy and X-ray diffraction techniques”. Cereal Foods World. 48(2): 78-81. Matsuda, D.K., A.E. Verceheze, G.M. Carvalho, F. Yamashita, S. Mali. 2013. “Baked foams of cassava starch and organically modified nanoclays”. Industrial Crops and Products 44: 705-711. Mello, L.R., S. Mali. 2014. “Use of malt bagasse to produce biodegradable baked foams made from cassava starch”. Industrial Crops and Products 55: 187-193. Montaldo, A. 1991. Cultivo de raíces y tubérculos tropicales. Instituto Interamericano de Cooperación para la Agricultura. San José, Costa Rica. Segunda Edición. 408 pp. Paes, S.S., I. Yakimets, J.R. Mitchell. 2008. “Influence of gelatinization process on functional properties of cassava starch films”. Food Hydrocolloids, 22(5): 788-797. Pagella, C., G. Spigno, D.M. De Faveri. 2002. “Characterization of starch based edible coatings”. Food and Bioproducts Processing, 80(3): 193-198. Palma-Rodríguez, H.M., J.D.J. Berrios, G. Glenn, R. Salgado-Delgado, A. Aparicio-Saguilán, A.I. Rodríguez-Hernández, A. Vargas-Torres. 2016. “Effect of the storage conditions on mechanical properties and microstructure of biodegradable baked starch foams”. CyTAJournal of Food 14(3): 415-422. Parra, D.F., C.C. Tadini, P. Ponce, A.B. Lugão. 2004. Mechanical properties and water vapor transmission in some blends of cassava starch edible films. Carbohydrate Polymers, 58(4): 475-481. Pérez, E. 1994. Caracterización de las propiedades funcionales de almidones nativos y modificados por métodos físicos de extrusión, deshidratación con doble tambor e irradicación gamma y microondas. Trabajo de ascenso. Facultad de Ciencias. ICTA. Universidad Central de Venezuela. Pérez, E., Y.A. Bahnassey, W.M. Breene. (1993). A simple laboratory scale method for isolation of amaranth starch. Starch‐Stärke, 45(6): 211-214.


310


Poovarodom, N., S. Praditduang. 1999. “The development of package from cassava starch”. Packaging Directory. Thailand, The Thai Packaging Association, 41-42. Pornsuksomboon, K., K.M. Szécsényi, B. Holló, K. Kaewtatip. 2014. “Preparation of native cassava starch and cross‐linked starch blended foams”. Starch‐Stärke 66(9-10): 818-823. Radley, J. 1976. Examination and analysis of starch and atarch products. Applied Science Publichers LTD, London. 220 pp. Ratnayake, W.S., D.S. Jackson. 2007. “A new insight into the gelatinization process of native starches”. Carbohydrate Polymers, 67(4): 511-529. Sarazin, P., G. Li, W.J. Orts, B.D. Favis. 2008. “Binary and ternary blends of polylactide, polycaprolactone and thermoplastic starch”. Polymer, 49(2): 599-609. Schmidt, V.C. 2006.Desenvolvimento de embalagens biodegradáveis a partir da fécula de cassava, calcário e fibra de celulose. Dissetac, ao de Mestrado em Engenharia de Alimentos. Universidade Federal de Santa Catarina (UFSC), Flori-anópolis, Brazil. Shey, J., S.H. Imam, G.M. Glenn, W.J. Orts. 2006. “Properties of baked starch foam with natural rubber latex”. Industrial Crops and Products, 24(1): 34-40. Shogren, R.L., J.W. Lawton, K.F. Tiefenbacher. 2002. “Baked starch foams: starch modifications and additives improve process parameters, structure and properties”. Industrial Crops and Products, 16(1): 69-79. Silva, R., E.M. Aquino, L.P. Rodrigues, A.R. Barros. Materia 2008 (Rio de Janeiro), 13(1): 154. Soykeabkaew, N., C. Thanomsilp, O. Suwantong. 2015. “A review: Starch-based composite foams”. Composites Part A: Applied Science and Manufacturing 78: 246-263. Soykeabkaew, N., P. Supaphol, R. Rujiravanit. 2004. “Preparation and characterization of jute-and flax-reinforced starch-based composite foams”. Carbohydrate Polymers, 58(1): 53-63. Thomas, D., W. Atwell. 1999. Starch structure. En Starches: Practical Guide for the Food Industry. Eagan Press. St. Paul. MN, EEUU. 1-12 pp. Tzoganakis, C. 1989. “Reactive extrusion of polymers: a review”. Advances in Polymer Technology, 9(4): 321-330. Vercelheze, A.E., F.M. Fakhouri, L.H. Dall’Antônia, A. Urbano, E.Y. Youssef, F. Yamashita, S. Mali. 2012. “Properties of baked foams based on cassava starch, sugarcane bagasse fibers and montmorillonite”. Carbohydrate Polymers 87(2): 1302-1310. Vercelheze, A.E.S., A.L. Oliveira, M.I. Rezende, C.M. Muller, F. Yamashita, S. Mali. 2013. “Physical properties, photo-and bio-degradation of baked foams based on cassava starch, sugarcane bagasse fibers and montmorillonite”. Journal of Polymers and the Environment 21(1): 266-274. Whistler, R., E. Paschall. 1967. Starch chemistry and technology. Academic Press. New York and London. Vol. II. Wurzburg, O.B. 1972. Starch in the food industry. Vol. I. Chap. 8. In: Hanbook of food additives. Segunda Edición. E.E. Furia. Editorial CRC Press. Boca Raton. Yu, L., K. Dean, L. Li. 2006. “Polymer blends and composites from renewable resources”. Progress in Polymer Science, 31(6): 576-602.



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BIOGRAPHICAL SKETCH Tomy J. Gutiérrez Affiliation: Composite Materials Group, Institute of Materials Science and Technology (INTEMA) (CONICET-UNMdP), Faculty of Engineering, National University of Mar del Plata and National Research Council (CONICET), Mar del Plata 7600, Argentina. Education: Degree in Chemistry. Central University of Venezuela. (12/07/2007). Degree in Education (Chemistry). Central University of Venezuela. (07/18/2008). Specialist in International Hydrocarbons Negotiation. National Experimental Polytechnic University of the Armed Forces. (07/06/2011). M.Sc. in Food Science and Technology. Central University of Venezuela. (10/31/2013). Ph.D. in Food Science and Technology. Central University of Venezuela. (24/04/2015). Doctoral Candidate in Metallurgy and Materials Science. Central University of Venezuela. (2015). Ph.D. in Materials Science. National University of Mar del Plata. (12/06/2016).

Business Address: [email protected]; [email protected] Research and Professional Experience: Food Science and Technology Polymers Science and Technology Petroleum and Natural Gas Publications Last 3 Years: 2014 (1): 1.- Tomy J. Gutiérrez*, Elevina Pérez, Romel Guzmán, María Soledad Tapia, Lucía Famá. (2014). Physicochemical and functional properties of native and modified by crosslinking, dark-cush-cush yam (Dioscorea Trifida) and cassava (Manihot Esculenta) starch. Journal of Polymer and Biopolymer Physics Chemistry, 2(1):1-5. doi: 10.12691/jpbpc-2-1-1. 2015 (6): 1.- Tomy J. Gutiérrez*, Noé J. Morales, Elevina Pérez, María Soledad Tapia, Lucía Famá. (2015). Physico-chemical study of edible films based on native and phosphating cush-cush yam and cassava starches. Food Packaging and Shelf Life, 3, 1-8. doi: 10.1016/j.fpsl.2014.09.002. 2.- Tomy J. Gutiérrez*, María Soledad Tapia, Elevina Pérez, Lucía Famá. (2015). Structural and mechanical properties of native and modified cush-cush yam and cassava starch edible films. Food Hydrocolloids, 45, 211-217. doi: 10.1016/j.foodhyd.2014.11.017.


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3.- Tomy J. Gutiérrez*, María Soledad Tapia, Elevina Pérez, Lucía Famá. (2015). Edible films based on native and phosphated 80:20 waxy:normal corn starch. Starch-Stärke, 67, 90-97. doi: 10.1002/star.201400164. 4.- Tomy J. Gutiérrez*, Noé J. Morales, María Soledad Tapia, Elevina Pérez, Lucía Famá. (2015). Corn starch 80:20 “waxy”:regular, “native” and phosphated, as bio-matrixes for edible films. Procedia Materials Science, 8, 304-310. doi: 10.1016/j.mspro.2015.04.077. 5.- Tomy J. Gutiérrez, Elevina Pérez*. (2015a). Chapter 1. Significant quality factors in the chocolate processing: cocoa post harvest, and in its manufacture. In: Chocolate: Cocoa Byproducts Technology, Rheology, Styling, and Nutrition. Editor Elevina Pérez Sira. Editorial Nova Science Publishers, Inc. NY. EE.UU. ISBN: 978-1-63482355-5. pp. 1-47. 6.- Yuniesky González Muñoz*, Tomy J. Gutiérrez. (2015b). Chapter 7. Evaluation of the sensory quality of chocolate. In: Chocolate: Cocoa Byproducts Technology, Rheology, Styling, and Nutrition. Editor Elevina Pérez Sira. Editorial Nova Science Publishers, Inc. NY. EE.UU. ISBN: 978-1-63482-355-5. pp. 167-189. 2016 (6): 1.- Tomy J. Gutiérrez*, Romel Guzmán, Carolina Medina Jaramillo, Lucía Famá. (2016). Effect of beet flour on films made from biological macromolecules: native and modified plantain flour. International Journal of Biological Macromolecules, 82, 395-403. doi: 10.1016/j.ijbiomac.2015.10.020. 2.- Tomy J. Gutiérrez*, Jusneydy Suniaga, Antonio Monsalve, Nancy L. García. (2016). Influence of beet flour on the relationship surface-properties of edible and intelligent films made from native and modified plantain flour. Food Hydrocolloids, 54, 234244. doi: 10.1016/j.foodhyd.2015.10.012. 3- Carolina Medina Jaramillo, Tomy J. Gutiérrez, Silvia Goyanes, Celina Bernal, Lucía Famá*. (2016). Biodegradability and plasticizing effect of yerba mate extract on cassava starch edible films. Carbohydrate Polymers, 151, 150-159. doi: 10.1016/j.carbpol.2016.05.025. 4.- Tomy J. Gutiérrez*, Gema González. (2016). Effects of exposure to pulsed light on surface and structural properties of edible films made from cassava and taro starch. Food and Bioprocess Technology,. doi: 10.1007/s11947-016-1765-3. 5.- Tomy J. Gutiérrez, Paula González Seligra, Carolina Medina Jaramillo, Lucia Famá*, Silvia Goyanes*. (2016). Effect of filler properties on the antioxidant response of thermoplastic starch composites. In: Handbook of Composites from Renewable Materials. Editors Vijay Kumar Thakur, Manju Kumari Thakur, Michael R. Kessler. WILEY-Scrivener Publisher. EE.UU. ISBN: 978-1-119-22362-7. 6.- Melina Bracone, Danila Merino, Jimena González, Vera A. Alvarez, Tomy J. Gutiérrez*. (2016). Chapter 6. Nanopackaging from natural fillers and biopolymers for the development of active and intelligent films. In: Natural Polymers: Their Derivatives, Blends and Composites. Editors Saiqa Ikram and Shakeel Ahmed. Editorial Nova Science Publishers, Inc. NY. EE.UU. ISBN: 978-1-63485-831-1.




Chapter 16

CASSAVA CULTIVATION, PROCESSING AND POTENTIAL USES IN GHANA Richard Bayitse1,*, Ferdinand Tornyie1,† and Anne-Belinda Bjerre2, , PhD ‡

1

Council for Scientific and Industrial Research, Institute of Industrial Research, Accra, Ghana 2 Danish Technological Institute, Taastrup, Denmark

ABSTRACT This review highlights the traditional and improved methods of cassava production and processing in Ghana. It also explains the geographical distribution of cassava production and utilisation. Facts and figures from agricultural production in Ghana is used to analyse production trends as well as the contribution of cassava to Agricultural Gross Domestic Production. Most importantly, cassava is a staple food crop and accounts for about 152.9 kg per capita consumption. Making it one of the most processed crop into gari, fufu powder and kokonte to increase its shelf life. Additionally, it can be used as an industrial crop because of its high starch content. These process technologies have contributed to the reduction of post-harvest losses in cassava production in Ghana. The residue generated from cassava processing has a huge potential in biorefinery. The review also brings into focus current research works in cassava residue utilisation, reviewing technologies for converting this valuable feedstock which is a mixture of cassava peels, trimmings and cuttings into sugar platform in a biorefinery for the production of major products such as ethanol, lactic acid and protein.

INTRODUCTION Cassava (Manihot esculenta Cralztz) is a starchy root crop which is an essential food eaten mainly by developing countries. The root tuber and leaves are edible and serve as *

[email protected]. [email protected]. ‡ [email protected]. †


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Richard Bayitse, Ferdinand Tornyie and Anne-Belinda Bjerre

source of nutritional food for about 500 million people and more worldwide. It is an important crop in developing countries because, it is a major food for households, drought tolerant, fairly resistance to plant disease, and extremely flexible in its cultivation, management requirements and harvesting cycles (FAO, 2002; Meridian Institute, 2009). Cassava is said to be the highest producer of carbohydrates when it comes to staple crops. According to the United Nations Food and Agriculture Organisation (FAO), cassava is graded fourth food crop in the developing countries, next to rice, maize and wheat (FAO, 2002). Cassava which is consumed in all the 10 regions of Ghana was introduced from Brazil, to the tropical areas of Africa by the Portuguese during the 16th and 17th centuries (Jones, 1959). During its introduction in Ghana, it was grown around trading ports, forts and castles and it was a major food that was eaten by slaves and the Portuguese as well. Around the second half of the 18th century, cassava had become the most commonly grown and eaten by majority of people along the coastlines of Ghana (Adams, 1957). Cassava cropping then spread from the coastlines of the country to all over the country progressively until it became a major staple food in most parts of the country following a serious drought in the year 1982/1983 when most crops failed dramatically (Korang-Amoakoh et al., 1987). Cassava then became a central food in Ghana that was eaten by various ethnic groups, processed in various forms. Currently, cassava occupies an important position in Ghana's agricultural economy and contribute about 46% of agricultural Gross Domestic Product (GDP). Cassava accounts for a daily calorie intake of 30% in Ghana and is grown by almost every farming family (FAO, 2000). Cassava as a food security crop can be used in various forms. It can be eaten raw by cooking, pounded into fufu or semi processed. Some processed forms include, gari, tapioca and flour for konkonte. It is also used as animal feed. Gari is exported to neighboring West African countries. Cassava is harvested at the farm and the tuber transported to a processing facility. These process technologies have contributed to the reduction of postharvest losses in cassava production in Ghana. The residue generated from cassava processing has a huge potential in biorefinery because it can easily be hydrolysed by appropriate enzymes into fermentable sugars.

PATTERN OF CASSAVA PRODUCTION Ghana is the sixth producer of cassava (15,113,000MT) in the world in terms of value and in terms of volume as in the year 2015, the third in Africa and the second among producers of fresh cassava roots in West Africa (FAO, 2015). Cassava is cultivated in all the 10 regions of Ghana. The five leading producers by regions on average over the past three years (2012-2014) included, Eastern: 4,307,372.22MT, Brong Ahafo: 3,460,907.08MT, Ashanti: 2,435,915.22MT, Central: 1,813,888.18MT, Northern: 1,403,454.35MT. Average area cropped per year between 1999 and 2004 was about 750,000 hectares, yielding about 10 million metric tonnes, increasing to 889,000 hectares in 2011 and producing 14 million metric tonnes (SRID-MoFA, 2012). However, in 2012 the total land area for cultivation dropped to 869,000 hecares but with slight increase in yield to 14.5 million metric tonnes of cassava increasing to 889,000 hectares of cultivated land in 2014 producing 16.5 million metric tonnes of cassava (SRID-MoFA, 2012, 2014). The bulk of the nation's cassava is produced in


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the south and middle part of Ghana, which accounts for roughly 78% of the total cassava production. Currently, Eastern region is the largest producer of cassava in Ghana accounting for 3 years average of 4.3 million metric tonnes spanning 2012-2014 (SRID-MoFA, 2014). Mean annual growth rate of area planted with cassava increased by 1.24% between 20032005 and 2006-2008 and a marginal decrease of 0.22% between 2009-2011 and 2012-2014 (SRID-MoFA, 2014). The decline is predicted to continue next year due to slight drought in the Sub-Sahara African (SSA) region. This is a treat to Ghana’s food security being that human population keeps increasing and cassava is a major staple food in the country (FAO, 2015).

CASSAVA CULTIVATION Over the years, cassava has been recognised as a major crop in Ghanaian agricultural and Africa in general. Although cassava was considered as a food security crop in most places where it had not previously been grown, notably in dry areas and marginal lands, the focus has gradually changed and it become a commercial crop for most farmers. This is due to the ability of the crop to withstand drought and thrive under harsh conditions (FAO, 2002). The major cassava planting season is mainly during the rainy season from April to November. With the intervention of new varieties in Ghana, Cassava is harvested approximately 12 months after planting. The largest percentage of the cassava root harvest comes onto the market in the early part of the wet season (May to July) before planting begins. Harvesting during the dry season (November to March) is in small quantities (Sam & Deppah, 2009). Mix cropping is common in Ghana and cassava is often mix cropped with maize, cocoyam, yam and cowpea. The crop is also rotated with some of these mix crops when farmers observe decline in soil fertility or productivity, the land is cropped to cassava for a period ranging between 12 to 18 months after which the maize/cowpea rotation is resumed. The total land area used for cassava cultivation increased by 18.5% since 2005. This increase in land use for cassava cultivation is as a result of its importance for industrial applications (FAO, 2002). Generally, the crop needs a warm and humid climate to grow with temperatures averaging 25-27ºC. The tropical lowlands with altitude below 150 m with annual rainfall from 500 mm to 5,000 mm are most suitable for higher root yield. Because the plant is resistance to prolong drought it is able to thrive in regions where annual rainfall is low or where seasonal distribution is irregular (USDA NRCS, n.d.). The crop is also able to grow on poor and degraded soil because it can withstand low pH, high level of exchangeable aluminum and low concentration of phosphorus in the soil matrix (Howeler, 2001). The agroecological regions of Ghana have mean annual rainfall varying between 800 mm and 2,200 mm (SRID-MoFA, 2014) making them very suitable for cassava cultivation. The soil pH vary from one ecological zone to the other but generally are in the range of 3.5 to 7.8. Ghana has a tropical climate with wet and dry seasons. The rainfall distribution is bimodal in the Forest, Transitional and Coastal Zones, giving rise to major and minor growing season; whiles Guinea Savannah and Sudan Savannah have unimodal distribution resulting in a single growing season (SRID-MoFA, 2014).


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The land is prepared for planting before the major rain starts in June. The slash and burn is carried out on virgin lands where planting is done for the first time. But lands which have been cultivated before are cleared without burning before planting is done. Hoes are used to make either small mounds or ridges for planting the cassava stick cuttings. Cutlasses and hoes are also used for weeding and cutting of planting materials. Currently tractors are not popularly used but with the inception of commercial farming, it is becoming a very useful tool for cassava cultivation. Stem cuttings of 20 cm lengths with an average weight of 0.085 kg/stem cutting are used as planting materials and are not pre-treated before planting. For traditional farms, about 3,240 stem cuttings are used per hectare, whiles commercial farms use 10,000 stem cuttings/hectare. Application of herbicides are not common for cassava cultivation for now but may be used when commercial farming takes off in full. Because cassava cultivation is rain fed, irrigation is not used for now. Mulching in cassava cultivation is done basically by allowing the slashed grasses mostly Andropogon on the field for some few days and then ploughed into the soil using hoes. This is done only once before planting. In most of the traditional farms fertilizers are not applied, but with the introduction of new concept, Integrated Crop Management (ICM), farmers are encouraged and trained on fertilizer application to increase yield. Demonstration farms are set up to teach farmers. Fertilizer application is done by using hand and containers. In cassava cultivation pruning is not common or not done, but weeding is done at intervals to prevent weed growth. When the plant is young this is done more frequently depending on the type of grass found at the farm and when the plant is grown, the frequency is reduced and at full maturity, the farms are not weeded. An average of 13 people are mostly involved in the cultivation of 1 hectare of cassava farm using about 78 man hours.

CASSAVA VARIETIES DEVELOPED AND CULTIVATED IN GHANA Over the years, there has been increase research of improved varieties of cassava in Ghana. The National Agricultural Research Systems (NARS) have released about 24 improved cassava varieties since 1993, which are high yielding, disease and pest resistant and mature early. Currently, Crop Research Institute of Council for Scientific and Industrial Research, Ghana, has released 11 improved varieties (CSIR-CRI, 2014). In Ghana, farmer’s preference for the variety they choose for cultivation is based on; yield, in-soil storage (longevity), disease resistance (Acheampong et al., 2013), utilisation purpose (multiple usages or the food type the cassava will be processed into) and readily available as planting materials. Nevertheless, new variety adoption by small scale farmers is very low leading to low outputs and incomes. There is low adoptability of high yielding improved cassava varieties in Ghana over the past 15 years due to low understanding of the varieties (Acheampong et al., 2013) and their management practices, and availability of planting materials. Farmer’s selection for varieties they cultivate is also based on the market value for the various varieties. For examples there is high value for cassava varieties that are used for preparing a local food called ‘fufu’ (pounded boiled cassava) because it is one of the delicacies for Ghanaians especially those in the south.



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FACTORS AFFECTING CASSAVA PRODUCTION Cassava production is faced with serious biotic constraints, such as diseases and pests, poor handling of planting materials, poor agronomic practices, limited technical know-how in cropping new varieties and poor postharvest handling and processing. The major factor that affects cassava production in SSA is pests of cassava; green mite and the variegated grasshopper. The main diseases affecting cassava are cassava mosaic disease (CMD), cassava bacterial blight, cassava anthracnose disease and root rot. In Africa, 50% of yield losses can be attributed to pests, disease and poor cultivation practices (FAO, 2002). Over the years, cassava production worldwide had been increasing remarkably at 4% p.a overtaking world population growth, however, due to unfavourable weather conditions, cassava production growth rate is predicted to reduce in 2015. This is probably going to be the first time phenomenon in virtually ten years, which could lead to the SSA production estimate of 163 million tonnes; a 3 million tonne drop from 2014. This drop over the SSA has reflected in the 0.2% drop in cassava production in Ghana in the year 2014. The drop has been partly attributed to El Niño and uncertain demand for cassava non-food products (FAO, 2013). Mechanisation, development of new technologies and new improve varieties of cassava and making planting material available at the right time will strengthen cassava production in the near future in Ghana. One of the main causes of low productivity of cassava in Ghana is the continuous use of indigenous, low yielding crop varieties (FAO, 2002; SRIDMoFA, 2014).

POLICY ON CASSAVA PRODUCTION IN GHANA The Ministry of Food and Agriculture (MoFA) is the lead ministry of Ghana government that is tasked with the responsibility of developing and executing policies and strategies for the development of the agriculture sector. Over the years, MoFA has been involved and leading various agriculture policies to improve agriculture production in Ghana. A lot of interventions have been made over the years by various organisations to develop cassava in the country however, government policies relegated the crop in favour of export crops such as cocoa, coffee and maize (Kleih et al., 2013). In the early 1930’s research works on cassava was directed toward high yields, low HCN content and excellent cooking qualities. Consequently, research and development (R&D) in cassava have focused on new high yielding varieties and improved pest, disease and drought resistance varieties. Since 1984, various projects have been rolled to improve cassava production in the country. Some of the interventions included: Ecologically Sustainable Cassava Plant Protection (ESCaPP) project; National Root and Tuber Crops Improvement Project (NTRCIP-1988) as a component of the International Fund for Agricultural Development (IFAD) sponsored Ghana Smallholder Rehabilitation and Development Programme (SRDP); National Agricultural Research Project (NARP); Medium-Term Agricultural Development Project (MTADP) in 1991; Food and Agriculture Sector Development Policy (FASDEP II) and the Medium Term Agriculture Sector Investment Plan (METASIP 2010-15); Root and Tuber Improvement and Marketing Programme (RTIMP) funded by IFAD and West African Agricultural Productivity Programme (WAAPP) to mention few (Kleih et al., 2013).


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CASSAVA HARVESTING AND PROCESSING Cassava as a staple food crop in Ghana can be eaten fresh by boiling in water and or pounded into traditional food called “fufu.” To achieve food security and to develop the agrobased economy in the rural areas to improve their living conditions, processing of cassava becomes very important. Cassava-based industrial food products have a potential of boosting the local economy. For industrialisation of cassava, it is necessary to improve upon the traditional methods of processing to improve the quality of product as well as to prolong the shelf life. Cassava harvesting is full of drudgery especially during the dry season when the soil is much firm and this has been a major constraint to commercial farmers. Cassava harvesting is usually manual by; cutting stem about 0.75meters above ground/leaving it uncut, the stem is held with both hands and pulled up to bring out the root from the soil. In instances that some of the roots remains in the soil, a hoe or cutlass is use to dig them out. In 2013, a mechanical cassava harvester called TEK mechanical harvester which is tractor drawn device was introduced. The device was tested and functions much better in the dry season when soils are much firmer, than during the wet season when soils are loose (WAAPP/PPAAO, 2013). The technology is yet to be adapted for commercial purpose.

TRADITIONAL CASSAVA PROCESSING Agro-processing activities in the rural levels are responsible for the preservation and distribution of most of Ghana’s agricultural produce. These activities play a major role in the post-harvest food system and are mainly carried out by rural women (IFAD, 2007) who employ very old and reliable traditional techniques in the processing of root and tuber crops. Traditional methods employed are simple and easy to use for their level of production. The equipment used for the traditional processes are cheaper compared to what is used for modern high technology processes. However, these traditional technologies produce products of relatively low quality coupled with high labour (Dziedzoave, et al. 1999; Westby, 2002). There are six (6) operational units involved in traditional cassava processing; peeling, chipping, grating, fermentation, sieving and frying/drying/roasting.

PEELING Cassava is peeled to remove none edible outer covering which is commonly known to contain most of the toxic cyanogenic glucosides. Peeling is usually done manually with hand using knife. Peeling is done either by slitting along the length of one side of the root with a knife followed by using the fingers to roll back the peels from the fleshy portion of the root, or by using the knife to slice the outer covering entirely from the flesh. Hand peeling is slow and laborious but it is the only method available now and used for cassava peeling in Ghana.



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Figure 1. Peeling of cassava by women at cassava processing facility at Bawjiase, Ghana.

CHIPPING Chipping is done to reduce the thickness of the cassava tuber thereby exposing the maximum surface area of the starchy flesh to facilitate quick drying. The drying process is affected by the size of the slice. It is known that thick slices take much longer time to dry because the rate of moisture diffusion from the inside is slower and the time for complete drying is longer. Usually sun-drying systems are effective when the chips are dried by passing air over them than by the direct effects of the sun’s rays. For efficient drying, the chip’s shape should allow air to readily circulate through a large mass of them.

FERMENTATION AND WATER REMOVAL Traditional operations normally combine both fermentation and water removal in one unit operation. The grated mash is put into jute bags, baskets, or any perforated material that allows water to drain and left to ferment for 1-5 days. During the fermentation, the sacks containing the cassava mash are twisted tightly and put on wooden boards with heavy stones pilled on them to press and remove the water (James et al., 2012; Quaye, Gayin, Yawson and Plahar, 2009). The fermentation process can be reduced by adding a starter culture in the form of seeding with previously fermented liquor. The fermentation process affects the quality of the product in terms of taste, colour and texture and must be properly controlled.

GRATING In traditional set up, grating is done manually with hand. But power operated graters of different models are also manufactured locally and used. Hand grating is a cumbersome


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operation and is normally done after washing and allowing excess water to drain from the cassava flesh to prevent the cassava from being slippery during grating. The manual grater is made up of galvanised metal sheet or a piece of flattened can or tin, punched with about 3mm diameter nails leaving a raised jagged flange on the underside. This grating surface is fixed on a wooden frame forming a dome shape or flat and the cassava pieces pressed against the jagged side of the metal and rubbed vigorously with strong downward movements. It is not possible to completely grate a whole cassava piece, 3% to 5% of the cassava had to be left ungrated. A skilful person is able to produce only about 20 kg/hour (Quaye et al., 2009).

SIEVING After pressing to remove the water, the relatively dry cassava mash is broken up and sieved to remove the large lumps and fibre to obtain a homogenous product. This is done by using sieves made from bamboo, palm leaves or raffia cane by rubbing and pressing the broken lump on the sieve with the palm. Mechanical sieves are also available and used in small commercial operations.

FRYING/ROASTING AND DRYING Frying of gari is a combination of two processes namely; roasting and drying. At the rural set up frying of gari is done in shallow aluminum pans, or in earthenware pans, over an open wood fire. The sieved cassava mash is spread thinly in the pan in 2-4kg batches depending on the size of the frying pan. A piece of calabash is often used to press the mash against the hot surface of the pan but scraped quickly and stirred constantly to keep the material moving to prevent it from burning until frying is completed at about 80° to 85°C. The quick heating partially gelatinises the gari which is dried during frying. The process takes 30-35 minutes, with the moisture content of the final product reduced to about 18% (Quaye et al., 2009).

GARI PROCESSING Gari is one of the most popular processed cassava products in all the cassava producing districts in Ghana. Traditional processing of gari from fresh cassava is made up of various unit operations of peeling, washing, grating, pressing and fermentation, sieving and roasting. The peeled tubers are washed thoroughly with water and grated by rubbing on the rough surface of a perforated galvanised metal sheet fixed to a wooden board support. The grated cassava mash is packed into jute bags and the open ends tied securely with rope. The loaded bags are then packed on wooden racks and heavy stones placed on them to squeeze out the starchy juice. After which fermentation is done for a period of about two days. The pressed fermented dough is dried in the Sun and sieved with traditional sieves. The sieved grains are roasted over fire in open cast iron frying pan with quick stirring until cooked and crisp. The roasted mass is again sieved to remove lumps, and packaged for storage and marketing (James et al., 2012; Quaye et al., 2009).



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Figure 2. Frying of gari using improved cook-stove in Kete Krachi, Ghana.

“KOKONTE” PROCESSING Traditional processing of cassava into “kokonte” requires less effort as compared to gari processing. The peeled roots are cut into small pieces and dried in the sun for 3 -6 days, depending on the sun’s intensity. Smaller pieces dry faster than the bigger one. Fermentation is achieved during drying, and this provided the desired aroma to the dried product. The potential of mould growth is reduced when drying is done rapidly. The dried product has a long shelf life and could be stored for several weeks as whole chips. This intermediate product is milled into flour and used in the preparation of a cooked traditional meal (Quaye et al., 2009).

AGBELIMA PROCESSING Traditional processing of cassava to fermented cassava dough is normally called “agbelima.” The unit processes involved is similar to gari processing as described earlier but the pressed and fermented product is not fried. This pressing and fermentation enhance the storage properties of the dough but only for a few days. The fermented dough is used for the preparation of Ghanaian dishes like (Akple or banku) and “Yakeyake.”


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PRODUCT DEVELOPED WITH HIGHLY QUALITY CASSAVA FLOUR (HQCF) In Ghana, several products have been developed using HQCF. A composite proportion of 1:4 of HQCF to wheat flour is use to bake bread adding other ingredients like milk, sugar, margarine, salt, nutmeg, baking powder etc. Pastries are made using cassava flour by replacing 75% of wheat flour in sponge cakes and chiffon cakes, 50% in butter cakes and cookies, and 25% in doughnuts and spaghetti. Noodles are also made from cassava flour by replacing 25-50% of the rice starch used and it gives a softer and elastic nature to the noodles (Dziedzoave et al., 2003). Cassava flour is used in the brewery industry to produce beer as in the Root beer; a popular beer in Ghana. The HQCF is also used as binding agents in food and plywood industry, and as adhesives to replace maize starch in starch-based adhesives.

INTEGRATED CASSAVA PROCESSING PLANT Over the years, various cassava processing machines have been designed to aid in one or two stages in the processing line. CSIR-Institute of Industrial Research, Ghana and other institutions have been instrumental in design and manufacturing of cassava processing machines with effort to integrate the various machines. An Integrated Cassava Processing Plant is designed to process 10-25metric tones of fresh cassava tubers into traditional fermented derivatives including gari, kokonte, agbelima vis-à-vis relatively new product of unfermented high quality cassava flour. Another unique feature of the plant is the incorporation of an animal feed processing unit that converts the cassava peels into animal feeds supplements to promote rearing of goats, sheep, cows etc. Three main machine incorporated into traditional process techniques to ensure production of unfermented high quality cassava flour are dryer for drying the sieved fine dough into flakes, hammer mill for milling and sieving the dried flour flakes and sifter to capture and finally sieve and grade the finely milled unfermented high quality cassava flour (Hahn, 2006; Selormey, et al. 2006).

HOW THE INTEGRATED CASSAVA PROCESSING PLANT TECHNOLOGY WORKS The technology involves peeling of cassava manually and carefully to ensure total removal of the peels without peeling off a greater portion of the flesh in which the starch tissues are contained. The peeled cassava is washed thoroughly with clean water in three (3)segment washing trough. Grating is done with a diesel-engine driven horizontal shaft Grater and/or a motorised vertical shaft Grater. The cassava mash can be fermented and used to process gari. The cassava mash captured in jute sacks are pressed with the help of a single manual screw and two double screw manual presses to dewater the cassava mash. The pressed dough is fed into the horizontal shaft drum Grater to disintegrate dough into fine granules and then sieved with a sieve which consists of a rotating drum with mesh. The roughages retained by the screen are considered by-product and used mostly as animal feed. The fine dough is dried with an electric dryer and after drying, the cooled flakes is fed into



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the mechanise hammer mill consisting of stainless steel hammer. The milled flakes are drown out of the hammer mill into a stainless steel hammer mill-blower-sifter-cyclone, falling by gravity into a hopper of a sifter guided with a slide to avoid overloading. Medium and coarse flour particles, which are not sieved are fed back into the hammer mill for further milling to obtain the fine high unfermented cassava flour. To make kokonte, after peeling and washing the cassava, the cassava is fed into motorises chipping machine to chip the cassava into smaller sizes and dried using a hybrid solar dryer to form kokonte. The peels are roughly milled and fed into a motorised feed mixing machine to make animal feed supplement (Dziedzoav, et al., 2006; Selormey, et al., 2006).

QUALITY IMPROVEMENT Cassava roots are an excellent source of carbohydrates. However, this food source has three major deficiencies: poor shelf-life, low content of protein and free amino acids, and high content of the poisonous cyanogenic glucosides (CNG): linamarin (96%) and lotaustralin (4%) (Cooke & Coursey, 1981). These cyanogens are distributed widely throughout the plant, with large amounts in the leaves and the root cortex (skin layer) and, generally, smaller amounts in the root parenchyma (interior). The designation of bitter and sweet varieties of cassava depends on the associated levels of toxicity (Sundaresan et al., 1987). Consumption of cassava products with high cyanogens levels may cause acute intoxications (Mlingi et al., 1992), aggravate goiter (Bourdoux et al., 1982) and, in severe circumstances, induce paralytic diseases (Tylleskar et al., 1992). To avoid dietary cyanide exposure, the glycosides and their metabolites, collectively known as cyanogens, must be removed by processing before consumption. Available research data confirms that peeling, first substantial process step lowers cassava toxicity, as the CNG distributed in large amounts in the root cortex (skin layer) is removed (Cooke & Coursey, 1981). Additionally, grating of the pulp, as the second step in processing, enables linamarin to have contact with its hydrolytic enzyme (linamarase), resulting in hydrolysis and subsequent removal of the breakdown products (Sornyotha et al., 2010). Fermentation is another process operation which has been observed to detoxify cassava. Fermentation experiment conducted by Lambri et al., (2013) confirmed that cultured microorganism played significant role in cynogen detoxification in cassava. They further concluded that yeast Saccharomyces cerevisiae, followed by Oenococcus oeni and Lactobacillus plantarum V22 were more effective in degrading linamarin after 24 hours than mixed cultures. These findings confirm the results of other researches (Tweyongyere & Katongole, 2002), regarding the fermentation of cassava roots soaked in water in which microbial growth was shown to be essential for the efficient elimination of cyanogens (Westby & Choo, 1994).


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POTENTIAL UTILISATION OF CASSAVA RESIDUES Cassava is harvested at the farm and the tuber transported to a processing facility. Cassava stalk and leaves are the major residues generated at the farm level. In 2014 about 3.7 million MT of cassava stalk was estimated to have been generated at farms using crop residue ration of 0.192 (Koopmans & Koppejan, 1997; OECD/IEA, 2010; SRID-MoFA, 2014). Cassava stalk is used as planting material and excess is sometimes burnt or left at the farm to decay. Stalks of new improved varieties are sold to farmers and in subsequent years enough is generated and excess becomes waste. Cassava leaves are also used for food by both humans and animals because of its nutritional value. Consumption of cassava leaves by humans is limited, but that of animals is prominent in areas of livestock rearing especially goats and sheep. Cassava leaves are considered as a good source of supplementary protein which can be used for preparing dishes in order to add variety to the diet as well as nutrition. The digestibility and nutritional value of cassava leaves have been investigated by Eggum, (1970) and Ravidran et al., (1987) who found it to be 80% for the protein in young leaves and 67% for the protein of older ones. Cassava leaves are good source of minerals. They are particularly rich in Ca, Mg, Fe, Mn and Zn. They are also rich in ascorbic acid and vitamin A and contain significant amount of riboflavin. But considerable losses of vitamins particularly of ascorbic acid occur during processing (Ravindran, n.d.). Cassava leaf yields amounting to as much as 4.60 MT dry matter per hectare may be produced as a by- product at root harvest (Ravindran & Rajaguru, 1988). Apart from cassava stalks and leaves generated at the farm levels, tons of cassava residue are generated at processing facilities. The cassava residue is composed of peels and trimmings. Peels normally consist of the thin pericarp and the thicker ring. Most processes remove both the pericarp and the thicker ring along with some pulp adhered to the peels. Analysis of the chemical composition of cassava peels indicates the following: dry matter 86.5–94.5%; organic matter 81.9–93.9%; crude protein 4.1–6.5%; hemicellulose and cellulose 34.4%; and lignin 8.4% (Kongkiattikajorn & Sornvoraweat, 2011). The composition of cassava residue make it a good resource for biorefinery. Composition analysis of the cassava residue by Bayitse et al., (2015) indicated that 47.16% was made up of starch, 2.40% protein and 83.41% glucose. Glucose is one of the major raw material in biorefinery and can be used to produce ethanol, lactic acid, and lysine. Cassava peel has some amount of crude protein as specified in composition analysis by Bayitse et al., (2015). The protein content of the cassava peel can be enhanced using solid state fermentation to make it more valuable in animal feed formulation. Solid state fermentation of cassava residue with Trichoderma pseudokoningii was conducted for 12 days. The fermentation was carried out at temperature of 24 °C and a pH of 5.0. Urea and ammonium sulphate were used as nutrient sources and moisture content varied at 60 and 70%. Protein content of the unfermented cassava residue was increased from 8.4 to 12.5% when urea was used with initial moisture content of 70% w/v. This study showed that a maximum of 48.1% protein enrichment was achieved using urea as a source of nutrient for the growth of the fungi, whiles ammonium sulphate achieved 36.9% protein enrichment under the same condition (Bayitse et al., 2015).



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Figure 3. Schematic diagram of biorefinary process of cassava peel (Bayitse, et al., 2015).

ETHANOL PRODUCTION Ethanol produced from lignocellulosic biomass is a potential alternative transportation fuel to none-renewable fossil fuels. Currently, the prevalent technique for cellulosic ethanol production is an enzyme based process because it is more environmentally friendly and produces a better hydrolysis yield than acid hydrolysis. Therefore, present cellulosic ethanol research is driven by the need to reduce the production cost (Mielenz, 2001). The enzyme based process primarily includes three steps such as biomass pretreatment, enzymatic hydrolysis and fermentation. Following the pretreatment, the enzymatic hydrolysis process can be designed in various ways. It can be run separately; separate hydrolysis and fermentation (SHF) or simultaneously; simultaneous saccharification fermentation (SSF). For either process, the key cost element to consider is that of the enzyme (Saddler & Gregg, 1998). For this reason, it is important to use the enzymes as efficiently as possible by creating a favourable environment in the hydrolysis step. This outcome could be realised by optimising operation methods (batch, fed-batch or continuous) and process parameters such as solid loading. In addition to enzyme concentration, solid loading is another important physical parameter that can affect the efficiency of cellulose hydrolysis. Although low solid loading could achieve high cellulose conversion, it would result in low yield of sugar concentrations for fermentation and ethanol for distillation thereby increasing ethanol recovery cost (Kongkiattikajorn, 2012). Also, low solid loading would increase both the capital cost of equipment and the operation costs in order to reach certain ethanol production capacity. Therefore, high solid loading is preferable and economically practical than low solid loading. However, the problems of sugar inhibitions and mixing with high solid loading need to be solved properly (Kongkiattikajorn, 2012).


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In fed-batch fermentation, solids and/or enzymes are added into reactors stepwise and solids are gradually degraded; thereby making the mixture more fluid creating adequate room for more solids to be added (Koppram and Olsson, 2014). As a result, fed-batch is expected to be a better procedure than batch on dealing with the situation of high solid loading and low enzyme concentration. Additionally, fed- batch can generate high glucose concentration for fermentation and finally yield high ethanol concentration for distillation resulting in significantly decrease of ethanol production cost (Ballesteros et al., 2002). Bacteria, yeasts and fungi are able to ferment xylose to ethanol. However, research showed yeasts are favourable for producing higher ethanol yields from xylose than the others. To date, the most extensively studied xylose- fermenting yeasts include Candida shehatae, Pachysolen tannophilus and Pichia stipitis. C. shehatae and P. stipitis are the best native ethanol producers from xylose, with yields approaching the theoretical maximum of 0.51 g ethanol /g xylose (Chu & Lee, 2007). The Baker's yeast Saccharomyces cerevisiae is normally accepted as safe microorganism for use in industrial wine making, brewing and baking processes to produce ethanol and CO2 from fermentable sugars respectively (van Zyl et al.,1989). Glucose fermentation is an anaerobic process that is used industrially for the production of ethanol with minimal formation of biomass and glycerol. Despite the efficiency of S. cerevisiae in glucose fermentation, it cannot utilise xylose effectively as a sole carbon source to ferment xylose to ethanol despite having a full xylose metabolic pathway (Batt et al., 1986). Ethanol yields and productivity from xylose fermentation by naturally occurring pentose-fermenting yeasts are significantly lower than glucose fermentation by S. cerevisiae, suggesting that there is considerable scope for improvement in xylose fermentation biotechnology (Chu & Lee, 2007). Recently, Olanbiwoninu and Odunfa, (2015) hydrolysed cassava peel into fermentable sugars using organic acid pre-treatment before enzyme hydrolysis. This process could add additional cost to the fermentation process but this has shown the potential of bioconversion of cassava peel into fermentable sugar. Bayitse et al., (2015) in their work to bioconvert cassava peel into fermentable sugars, evaluated enzymatic hydrolysis of cassava peel using cellulase and beta-glucanase enzymes and their mixtures at three different enzyme loadings with time. The pH of the medium used for hydrolysis was 5 and the temperature was 50 °C. They reported that efficiency of the hydrolysis using beta-glucanase was better than cellulase and glucose recovery of 69% was realised when beta-glucanase dosage was increased to 10% (v/w) at 48 h which rose to 73% at 120 h, releasing 11.19 g/l and 12.17 g/l of glucose respectively. Less than 20% of glucose was hydrolysed at 10% (v/w) cellulase at 120 h releasing 2.6 g/l glucose. The optimum experimental condition for hydrolysis of cassava peel was established at 120 h when glucose recovery increased to 88% for enzyme mixture of 5% (v/w) cellulase + 10% (v/w) beta-glucanase producing 14.67 g/l glucose in the hydrolysate. To obtain high concentration of ethanol from cassava peel, Kongkiattikajorn, (2012) pretreated cassava peel with acid to remove noncellulose components, and then subjected it to simultaneous saccharification and fermentation (SSF). An ethanol concentration as high as 7.62 g/L was realized with 2.5% dry matter (DM) using batch SSF, producing 84.34% overall ethanol yield. He further investigated a fed-batch process using a high solid concentration. Dry substrate was pretreated with steam and dilute sulfuric acid at 135°C under pressure of 15 lb/in 2, and then added at different amounts during the first 24 h, to yield a final dry matter content of 20% (w/v). Fed batch SSF conditions with cellulase loading of 100 FPU/g,



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xylanase 25 IU/g, pectinase 25 IU/g and amylase with amyloglucosidase loading of 50 and 75 U/g, respectively, yeast (Saccharomyces cerevisiae) loading of 2 g/L and substrate supplementation every 4 h yielded the highest ethanol concentration of 58.73 g/L after 72 h. This corresponded to a 76.47% overall ethanol yield. The upscale process for ethanol production using cassava peel was conducted by Bayitse et al., (2015). They pretreated the cassava peel by wet milling followed by simultaneous saccharification and fermentation. Their findings suggested that intermittent wet milling with α-amylase has increased glucose concentration over five-fold from the initial concentration of 1.36 mg/L. Simultaneous saccharification using the optimal condition of enzymes (amyloglucosidase, β-glucanase and cellulase) has increased the glucose concentration in the hydrolysate from 5.5 g/L to 75.5 g/L after wet-milling. Fermentation was carried out for 72 hours, but the optimum was reached after 24 hours without additional nutrient supplements. High-Performance Liquid Chromatography analysis of the fermented broth recorded 46.52 g/L of ethanol which represented 98% of theoretical ethanol yield.

LACTIC ACID PRODUCTION Industrial scale production of lactic acid demands availability of sustainable cheap raw materials with low level of contamination. Biomass as raw material in the form of starch (corn, wheat, potato, cassava, rice and sweet sorghum) and lignocelluloses (corn cobs, waste paper and woody materials) can be used as a substrate for fermentation of lactic acid (Oh et al., 2005; Richter & Berthold, 1998). Biomass from agricultural crop residues can be put into two major categories. The primary category is obtained as a by-product of agricultural post-harvesting activities, normally from the harvesting and processing of staple crops for domestic use. The secondary category is generated from industrial processing of agricultural crops. Cereal crop mills and food processing industries are directly involved in biowaste generation from agricultural residues (Mohammed et al., 2013). Lactic acid production can be done either by fermenting sugars or hydrolysates containing sugars. It can also be produced by converting starchy or cellulosic materials using lactic acid producing microorganisms. Simultaneous hydrolysis and fermentation with saccharifying enzymes is widely deployed. The use of hydrolysate is preferred to refined sugars for solid state or submerged fermentation of lactic acid (John et al., 2006). The hydrolysis of starch or cellulose to sugar is a high energy utilisation process which can increase the cost of production. Woiciechowski et al., (1999) in their study of hydrolysis of cassava bagasse starch by acid and enzyme reported that, both methods were quite efficient when considering one or the other parameter like the percentage of hydrolysis, time and cost of the chemicals and energy consumption. Although acid hydrolysis is time saving and cost effective, there is always a neutralising step after acid hydrolysis. This will increase the level of salts in the medium and affect the microbial growth and production of lactic acid. Conventional fermentative production of lactic acid from starch materials requires a pretreatment process that involves gelatinisation and liquefaction, which is carried out at a temperature between 90 and 130 °C for 15 min followed by long time enzymatic


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saccharification to glucose at a higher temperature, and subsequent conversion of glucose to lactic acid by fermentation. Anuradha et al., (1999) conducted batch experiments to establish optimum operating conditions for the simultaneous saccharification and fermentation (SSF) of starch to lactic acid using Lactobacillus delbrueckii. They developed a predictive model for SSF by combining the kinetics of saccharification and fermentation. Their results showed that saccharification rate was always higher for SSF than in simple saccharification (SS) at all substrate concentrations. Nwokoro, (2014) produced L-lactic acid using cultures of Rhizopus oligosporus and Lacto- bacillus plantarum from cassava peel. He hydrolysed cassava peels for 1 hour in both NaOH and HCl by boiling after which the hydrolysates were neutralised to a pH of 6.2. He reported that there were proportional increase in reducing sugar with increasing concentrations of alkali or acid. Higher concentration of reducing sugar (402 mg/g) was realised in the acid hydrolysate as compared with 213 mg/g reducing sugar concentration in alkali hydrolysate. He further added 0.5% ammonium sulphate solution to the hydrolysates and inoculated with either single or mixed cultures of R. oligosporus and L. plantarum and incubated for 48 hours for lactic acid production. He concluded that the best lactic acid production of 50.2 g/100 g substrate was observed in a mixed culture fermentation of acid hydrolyzed peels as compared with 36.4 g/100g substrate of alkali hydrolysed peels. However, unhydrolysed cassava peels inoculated with a mixed culture of the microorganisms produced only 4.6 g/100g substrate. His conclusion also buttress the point that the lactic acid bacteria need reducing sugar to produce lactic acid. Fibrous residue is a major waste produce during cassava starch extraction. Because of the high starch content (60-65% on dry weight basis) and organic matter of cassava fibrous residue (CFR), research has been conducted to utilise it for the production of lactic acid (LA) in semi solid state fermentation using Mann Rogassa Sharpe medium containing [5% (wv (1))] CFR in lieu of glucose [2% (wv (-1))] as the carbon source. Response Surface Methodology (RSM) was used to evaluate the effect of main variables, i.e., incubation period, temperature and pH on LA production. The experimental results showed that the optimum incubation period, temperature and pH were 120 hours 35 degrees C and 6.5, respectively. Maximum starch conversion by Lactobacillus plantarum MTCC 1407 to LA was 63.3%. The organism produced 29.86 g of (L+) LA from 60 g of starch present in 100 g of CFR. The LA production yield was 49.76%. (Ray et al., 2009).

CONCLUSION Cassava has been recognised as a major crop in Ghanaian agricultural systems and has been grown in almost all the 10 regions in the country. The major cassava planting season is mainly during the rainy season from April to November. With the intervention of new varieties in Ghana, cassava is harvested approximately 12 months after planting. The bulk of the nation's cassava is produced in the south and middle part of Ghana, which accounts for roughly 78% of the total cassava production. Currently, Eastern region is the largest producer of cassava in Ghana accounting for 3 years average of 4.3 million metric tonnes spanning 2012-2014. The total land area used for cassava cultivation increased by 18.5% since 2005.



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This increase in land use for cassava cultivation is as a result of its importance for industrial applications. Most importantly, cassava is a staple food crop and accounts for about 152.9 kg per capita consumption, making it one of the most processed crop into gari, fufu powder, Highly Quality Cassava Flour (used for bakery products) and kokonte to increase its shelf life. Additionally, it can be used as an industrial crop because of its high starch content. These process technologies have contributed to the reduction of post-harvest losses in cassava production in Ghana. The residue generated from cassava processing has a huge potential in biorefinery for the production of major products such as ethanol, lactic acid and protein.

REFERENCES Acheampong, P., Owusu, V. and Gyiele K. N. (2013). 203-Farmers Preferences for Cassava Variety Traits: Empirical Evidence from Ghana. In Fourth International Conference of the African Association of Agricultural Economists (pp. 1–21). Hammamet, Tunisia. Adams, C. (1957). Activities of Danish Botanists in Guinea 1738–1850. Transactions of the Historical Society of Ghana III. Part 1. Anuradha, R., Suresh, A. K. and Venkatesh, K. V. (1999). Simultaneous saccharification and fermentation of starch to lactic acid. Process Biochemistry, 35(3-4), 367–375. http://doi.org/10.1016/S0032-9592(99) 00080-1. Ballesteros, M., Oliva, J. M., Manzanares, P., Negro, M. J. and Ballesteros, I. (2002). Ethanol production from paper material using a simultaneous saccharification and fermentation system in a fed-batch basis. World Journal of Microbiology and Biotechnology, 18(6), 559–561. http://doi.org/10.1023/A:1016378326762. Batt, C. A., Carvallo, S., Easson, D. D., Akedo, M. and Sinskey, A. (1986). Direct evidence for a xylose metabolic pathway in Saccharomyces cerevisiae. Biotechnol Bioeng, 28, 549–53. Bayitse, R., Hou, X., Laryea, G., Aggey, M., Oduro, W., Selormey, G. and Bjerre, A.-B. (2015). Ethanol process from biowaste c5 and c6. Brussels. Retrieved from http://www.biowaste4sp.eu. Bayitse, R., Hou, X., Bjerre, A.-B. and Saalia, F. K. (2015). Optimisation of enzymatic hydrolysis of cassava peel to produce fermentable sugars. AMB Express, 5(1), 60. http://doi.org/10.1186/s13568-015-0146-z. Bayitse, R., Hou, X., Laryea, G. and Bjerre, A.-B. (2015). Protein enrichment of cassava residue using Trichoderma pseudokoningii (ATCC 26801). AMB Express, 5(1), 80. http://doi.org/10.1186/s13568-015-0166-8. Bourdoux, P., Seghers, P., Mafuta, M., Vandrpas-Rivera, M., Delange, F. and Ermans, A. M. (1982). Cassava products: HCN content and detoxification process. In E. A. Delange F, Iteke FB (Ed.), Nutritional factors involved in the goitrogenic action of cassava (pp. 51– 58). Ottawa, Canada: IDRC-184e. IDRC. Chu, B. C. H. and Lee, H. (2007). Genetic improvement of Saccharomyces cerevisiae for xylose fermentation. Biotechnology Advances, 25(5), 425–441. http://doi.org/10.1016/ j.biotechadv.2007.04.001.


330


Cooke, R. D. and Coursey, D. G. (1981). Cassava: a major cyanide containing food crop. In F. Vennesland, B; Conn, E; Knowles, C; Westley, J; Wissing (Ed.), Cyanide in biology (pp. 93–114). London: Academic Press. CSIR-CRI. (2014). The National Centre of Specialisation for Root and Tuber Crops Research. (R. Baning, I.S, Adu-Donyinah, Ed.). Kumasi, Ghana.: CSIR-Crops Research Institute. Dziedzoav, N. T., Abass, A. B., Amoa-Awua, W. K. A. and Sablah, M. (2006). Quality Management Manual for Production of High Quality Cassava Flour. Dziedzoave, N. T., Ellis, W. O., Oldham, J. H. and Osei-Yaw, A. (1999). Subjective and Objective assessment of agbelima (Cassava dough) quality. Food Control, 10(2), 63–67. Dziedzoave, N. T., Graffham, A. J. and Boateng, E. (2003). Training manual for the production of cassava-based bakery products. CSIR-FRI, Accra, Ghana. Eggum, R. O. (1970). “The protein quality of cassava leaves.” Br. J. Nutr., 24, 761–768. Retrieved from sciencedirect.com. FAO. (2000). A review of cassava in Africawith country case studies on Nigeria, Ghana,the United Republic of Tanzania, Uganda and Benin. Retrieved December 22, 2014, from http://www.fao.org/docrep/009/ a0154e/A0154E01.htm. FAO. (2002). Protein sources for the animal industry. FAO Expert Consultaion and Workshop. http://doi.org/Expert Consultation and Workshop Bangkok, 29 April - 3 May 2002. FAO. (2002). The State of Food and Agriculture. Rome. FAO. (2013). Cassava Farmer Field Schools: Resource material for facilitators in subSaharan Africa. FAO. (2015). Food Outlook, Biannual report on global food markets. Hahn, S. K. (2006). An overview of traditional processing and utilization of cassava in Africa. Howeler, R. H. (2001). Cassava mineral nutrition and fertilization. Cassava: Biology, Production, and Utilization, 115–147. http://doi.org/10.1079/97 80851995243.0115. IFAD. (2007). Improving marketing strategies in Central and West Africa. Rural Poverty Portal,. James, B., Okechukwu, R., Abass, A., Fannah, S., Sanni, L., Fomba, S. and Lukombo, S. (2012). Producing Gari from Cassava: An illustrated guide for smallholder cassava processors. International Institute of Tropical Agriculture (IITA): Ibadan, Nigeria. John, R. P., Nampoothiri, K. M. and Pandey, A. (2006). Solid-state fermentation for l-lactic acid production from agro wastes using Lactobacillus delbrueckii. Process Biochemistry, 41(4), 759–763. http://doi.org/10.1016/ j.procbio.2005.09.013. Jones, W. O. (1959). Manioc in Africa. (F. R. Institute, Ed.). Stanford, USA: Stanford University. Kleih, U., Phillips, D. and Wordey, M. T. (2013). Cassava Market and Value Chain Analysis Ghana Case Study Final Report (Anonymised version) February 2013, (January). Retrieved from http://www.value-chains.org/dyn/bds/docs/859/GhanaCassavaMarket Study-FinalFebruary 2013_anonym.pdf. Kongkiattikajorn, J. (2012). Ethanol Production from Dilute-Acid Pretreated Cassava Peel by Fed-Batch Simultaneous Saccharification and Fermentation. International Journal of the Computer, the Internet and Management, 20(2), 22–27.



331

Kongkiattikajorn, J. and Sornvoraweat, B. (2011). Comparative Study of Bioethanol Production from Cassava Peels by Monoculture and Co-Culture of Yeast. Kasetsart J. (Nat. Sci.), 274, 268–274. Koopmans, A. and Koppejan, J. (1997). Agricultural and forest residues generation, utilisation and availability. Retrieved February 12, 2013, from wgbis.ces.iisc.ernet.in/energy/ HC270799/RWEDP/acrobat/p_residues.pdf. Koppram, R. and Olsson, L. (2014). Combined substrate, enzyme and yeast feed in simultaneous saccharification and fermentation allow bioethanol production from pretreated spruce biomass at high solids loadings. Biotechnology for Biofuels, 7(1), 54. http://doi.org/10.1186/1754-6834-7-54. Korang-Amoakoh, S., Cudjoe, R. A. and Adams, E. (1987). Biological control of cassava pests in Ghana. Prospects for the integration of other strategies. Lambri, M., Fumi, M. D., Roda, A. and De Faveri, D. M. (2013). Improved processing methods to reduce the total cyanide content of cassava roots from Burundi. African Journal of Biotechnology, 12(19), 2685–2691. http://doi.org/10.5897/AJB2012.2989. Meridian Institute. (2009). Science and Innovation for African Agricultural Value Chains: Lessons learned in transfer of technologies to smallholder farmers in Sub-Saharan Africa. New Growth International. Mielenz, J. R. (2001). Ethanol production from biomass: technology and commercialization status. Current Opinion in Microbiology, 4(3), 324–329. http://doi.org/10.1016/S13695274(00)00211-3. Mlingi, N. L. V., Poulter, N. H. and Rosling, H. (1992). An outbreak of acute intoxi-cation from insufficiently processed cassava in Tanzania. Nutr. Res., 12, 677–687. Mohammed, Y. S., Mokhtar, A. S., Bashir, N. and Saidur, R. (2013). An overview of agricultural biomass for decentralized rural energy in Ghana. Renewable and Sustainable Energy Reviews, 20, 15–25. http://doi.org/10.1016/j.rser.2012.11.047. Nwokoro, O. (2014). Production of L-lactic acid from Cassava peel wastes using single and mixed cultures of Rhizopus oligosporus and Lactobacillus plantarum. Chemical Industry and Chemical Engineering Quarterly, 20(4), 457–461. http://doi.org/10.2298/CICEQ 130325027N. OECD/IEA. (2010). Sustainable production of second-generation biofuels, potential and perspectives in major economies and developing countries, Information paper. Retrieved February 12, 2010, from www.iea.org/ papers/2010/second_generation_biofuels.pdf. Oh, H., Wee, Y.-J., Yun, J.-S., Ho Han, S., Jung, S. and Ryu, H.-W. (2005). Lactic acid production from agricultural resources as cheap raw materials. Bioresource Technology, 96(13), 1492–8. http://doi.org/10.1016/ j.biortech.2004.11.020. Olanbiwoninu, A. A. and Odunfa, S. A. (2015). Production of Fermentable Sugars from Organosolv Pretreated Cassava Peels. Advances in Microbiology, (February), 117–122. Quaye, W., Gayin, J., Yawson, I. and Plahar, W. (2009). Characteristics of various cassava processing methods and the adoption requirements in Ghana. Journal of Root Crops, 35(1), 59–68. Retrieved from http://www.researchgate.net/publication/228308346_ Characteristics_of_Various_Cassava_Processing_Methods_and_the_Adoption_Requirem ents_in_Ghana/file/9fcfd50fd8dea34263.pdf. Ravidran, V., Kornegay, E. T., Rajaguru, A. S. B. and Notter, D. (1987). “Cassava leaf meal as a replacement for coconut oil meal in pig diets.” Journal of the Science of Food and Agriculture, 41, 45–53. Retrieved from sciencedirect.com.


332


Ravindran, V. and Rajaguru, A. S. B. (1988). “Effect of stem pruning on cassava root yield and leaf growth.” Sri Lankan Journal of Agricultural Science, 24(2), 32–37. Retrieved from sciencedirect.com. Ravindran, V. (n.d.). Preparation of cassava leaf products and their uses as animal feeds. Retrieved February 11, 2013, from Fao.org/ag/aga/agap/ frg/ahpp95/95111.pdf>. Ray, R. C., Sharma, P. and Panda, S. H. (2009). Lactic acid production from cassava fibrous residue using Lactobacillus plantarum MTCC 1407. Journal of Environmental Biology, 30(5 SUPPL.), 847–852. Richter, K. and Berthold, C. (1998). Biotechnological Conversion of Sugar and Starchy Crops into Lactic Acid. Journal of Agricultural Engineering Research, 71(2), 181–191. http://doi.org/10.1006/jaer.1998.0314. Saddler, J. N & Gregg, D. (1998). Ethanol production from forest products wastes. In J.. Bruce, A and Palfreyman (Ed.), Forest products biotechnology (pp. 183– 207). London: Taylor & Francis Ltd. Sam, J. and Deppah, H. (2009). West African Agricultural Productivity Programme – Ghana Baseline Survey Report. Selormey, G., Amoah, J. Y. and Aggey, M. (2006). Diversification of cassava(Manihotesculenta Crantz)utilization in Northern Ghana – A case study: Integrated cassava processing pilot plant in Salaga-Kpembe.” In Proceedings of the 3rd National Conference on Agriculture Engineering. Kumasi, Ghana.: Kwame Nkrumah University of Science and Technology. Sornyotha, S., Kyu, K.L. and Ratanakhanokchai, K. (2010). An efficient treatment for detoxification process of cassava starch by plant cell wall-degrading enzymes. J. Biosc. Bioeng., 109, 9–14. SRID-MoFA. (2012). Agriculture in Ghana (Facts and figures 2012). Ministry of Food and Agriculture. Retrieved from https://www.itu.int/ITU-D/ict/facts/2011/material/ICTFacts Figures2011.pdf. SRID-MoFA. (2014). Agriculture in Ghana (Facts and Figures). Ministry of Food and Agriculture. Retrieved from http://facts/mofa.gov.gh/site/wp-content/uploads/.../mofa_ facts_and_figures.pdf. Sundaresan, S., Nambisan, B. and Easwari Amma, C. S. (1987). Bitterness in cassava in relation to cyano-glucoside content. Indian J. Agric. Sci., 57, 34–40. Tweyongyere, R. and Katongole, I. (2002). Cyanogenic potential of cassava peels and their detoxification for utilization as livestock feed. Vet. Hum. Toxicol., 44, 366–369. Tylleskar, T., Banea, M., Bikangi, N., Cooke, R. D., Poulter, N. H. and Rosling, H. (1992). Cassava cyanogens and konzo, an upper motoneuron disease found in Africa. Lancet, 339, 208–211. USDA NRCS. (n.d.). Plant Guide. Louisiana and Pacific Islands. Retrieved from . van Zyl, C., Prior, B. A., Kilian, S. G. and Kock, J. L. (1989). D-xylose utilization by Saccharomyces cerevisiae. Journal of General Microbiology, 135(11), 2791–8. Retrieved from http://www.ncbi.nlm.nih. gov/pubmed/2515242. WAAPP/PPAAO. (2013). Mechanical cassava harvester. Retrieved July 28, 2016, from www.waapp.org.gh. Westby, A. and Choo, B. (1994). Cyanogen reduction during the lactic fermentation of cassava. Acta Horticulturae, 375, 209–215.



333

Westby, A. (2002). Cassava utilization, storage and small-scale processing. In A. C. Hillocks, R. J., Thresh, J. M. and Bellotti (Ed.), Cassava biology, production and utilization (pp. 281–300). Wallingford, UK: CABI Publishing. Woiciechowski, A. L., Soccol, C. R., Ramos, L. P. and Pandey, A. (1999). Experimental design to enhance the production of l-(+)-lactic acid from steam-exploded wood hydrolysate using Rhizopus oryzae in a mixed-acid fermentation. Process Biochemistry, 34(9), 949–955. http://doi.org/ 10.1016/S0032-9592(99)00012-6.





Chapter 17

POTENTIAL USES OF CASSAVA BAGASSE FOR BIOENERGY GENERATION BY PYROLYSIS AND COPYROLYSIS WITH A LIGNOCELLULOSIC WASTE Luciano I. Gurevich Messina1,3, Pablo R. Bonelli1,3 and Ana L. Cukierman1,2,3,* 1

Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Depto. de Industrias, Programa de Investigación y Desarrollo de Fuentes Alternativas de Materias Primas y Energía (PINMATE), Ciudad Universitaria. Buenos Aires, Argentina 2 Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Depto. de Tecnología Farmacéutica, Cátedra de Tecnología Farmacéutica II. Buenos Aires, Argentina 3 Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina

ABSTRACT Cassava (Manihot esculenta) bagasse is a fibrous by-product generated in the tuber processing. After washing and peeling, the cassava is grated and then water is added in order to extract the starch. The mixture is filtered such that a rich starch solution and a wet solid residue can be separated. This slurry, known as bagasse, comprises up to 20% of the weight of the processed cassava. In addition, as the extraction of starch from cassava is less efficient than those based on processing of potato or maize, the bagasse contains around 50-70% of starch on a dry basis. As it has no important use, with the exception of animal feed, the bagasse is usually rejected to water courses increasing the environmental pollution. Therefore, several strategies are being studied to find useful applications for this by-product. Pyrolysis of the bagasse and copyrolysis, namely the thermal degradation of mixtures of the bagasse and lignocellulosic biomass in inert atmosphere, could be an appealing possibility to employ this waste in order to generate *

E-mail: [email protected]; [email protected].


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Luciano I. Gurevich Messina, Pablo R. Bonelli and Ana L. Cukierman green energy and/or other value-added products. In particular, growing attention is paid to the liquid products arising from pyrolysis/copyrolysis, commonly known as bio-oils, since they show many of the advantages of liquid fuels, such as inexpensive storage and transportation, and high energy density. In this scenario, the processes of pyrolysis of cassava starch, the major constituent of dry cassava bagasse, and of copyrolyisis of the starch with peanut hulls, an abundant lignocellulosic residue, were studied by performing experiments in a fixed-bed reactor at different process temperatures (400ºC – 600ºC). The pyrolysis of the starch led to a higher maximum yield of bio-oils that took place at a lower temperature than the copyrolysis (57 wt% at 400ºC vs. 49 wt% at 500ºC). Physichochemical characterization of the three kinds of pyrolysis/copyrolysis products with emphasis on the bio-oils was carried out mainly by proximate and ultimate analyses, Karl-Fischer titration, Fourier-transformed infrared spectroscopy, N2 adsorption, scanning electronic microscopy, and gas chromatography (GC-TCD and GC-MS). While the pyrolysis of the starch resulted in bio-oils with less nitrogen content, the copyrolysis produced bio-oils with lower content of oxygen and higher carbon percent. Water content of the bio-oils increased with rising process temperatures and it was lower for the liquids resulting from the pyrolysis of the starch. Also, the bio-oils arising from the pyrolysis of the starch presented more sugar compounds and fewer phenols. Besides, the pyrolysis of the starch led to a lower yield of solid products (bio-chars) than the copyrolysis. They showed greater high heating values (up to 35 MJ/kg) than those arising from the latter process in agreement with their larger carbon content and lower presence of ash. In addition, the bio-chars produced at the highest process temperature presented an incipient pore development, suggesting their possible use as rough adsorbents or as intermediary for further upgrading to activated carbons. Furthermore, the pyrolysis of cassava starch and copyrolysis with peanut hulls generated gases, principally CO 2, CO, CH4 and H2, that could help to sustain the processes.

Keywords: cassava bagasse, cassava starch, pyrolysis, copyrolysis, bioenergy, bio-oils

1. INTRODUCTION Growing demand of energy worldwide along with depleting reserves of fossil fuels has led to the search of renewable alternative sources. Biomass as an energy source has several advantages because its use is essentially carbon neutral and it provides a convenient way of storing energy compared to other renewable energies. Energy generation from biomass or bioenergy has great potentialities for sustainable supply of electricity, domestic heat, fuels for transport, and process heat for industrial facilities, with beneficial impact on the environment, particularly due to reduction in greenhouse gas emissions related to fossil fuels employment (Cherubini and Strømann, 2011). Biomass is considered as the most important source of energy (Frau et al., 2015). Contribution of bioenergy to the global energy matrix is currently around 10% (~50 EJ) and estimations forecast a technical potential higher than 1500 EJ in 2050 (Ullah et al., 2015). Among possible biomass sources, agricultural and agro-industrial residues have received increasing attention in the search of alternatives to the relatively more conventional forestry and/or wood wastes. The former ones encompass agricultural wastes such as straw, stem, stalk, leaves, husk, shell, peel, lint, seed/stones, pulp, stubble, arising from cereals, like rice, wheat, maize or corn, sorghum, barley, millet, cotton, groundnut, jute, legumes, coffee, cacao, olive, tea, fruits and palm oil. Likewise, agro-industrial residues are derived from the


Potential Uses of Cassava Bagasse for Bioenergy Generation …

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processing of a particular crop or animal product. This category includes materials like molasses, bagasse, oilseed cakes, maize milling by-products and brewer’s wastes, among others (Menon and Rao, 2012; Long et al., 2013). In particular, cassava (Manihot esculenta) is a root crop whose industrial processing generates large amounts of residue. It is classified as the fifth most abundant starch crop produced in the world and the third most important food source for inhabitants of tropical regions (Debiagi et al., 2015). Copious solid and liquid wastes emerge from processing of cassava tubers for the large-scale production of starch. The bagasse, namely the fibrous byproduct of the root containing part of the starch that was not previously extracted and fiber, is an important residue. After washing and peeling, the cassava is grated and then water is added in order to extract the starch. The mixture is filtered such that a rich starch solution and a wet solid residue can be separated. This slurry, known as bagasse, comprises up to 20% of the weight of the processed cassava tuber. In addition, as the extraction of starch from cassava is less efficient than those based on processing of potato or maize, the bagasse contains around 50-70% of starch on a dry basis. As it has no important use, with the exception of animal feed, cassava bagasse is usually rejected to water courses without any treatment leading to serious environmental pollution in areas where starch industries are located (Jyothi et al., 2005). Several strategies are being studied to find useful applications for cassava bagasse, such as the production of lactic acid by bacteria, production of ethanol, and development of biodegradable packaging (Pandey et al., 2011; Debiagi et al., 2015; Zhang et al., 2016). Despite cassava bagasse can be considered as a rich solar energy reservoir due to cassava’s easy regeneration capacity, in comparison to other agricultural residues, its conversion has been mostly investigated through the biochemical route, while thermochemical processes have been scarcely explored. Bio-energy generation via thermochemical conversion has advantages in comparison to the biochemical route, involving higher reaction rates and superior capacity to destroy organic matter (Zhang et al., 2010). Another advantage in the same direction is the relatively low ash content characterizing cassava bagasse (Pandey et al., 2000). Main thermochemical conversion processes for generation of bioenergy or energy carriers from biomass include combustion, pyrolysis, gasification, and liquefaction. In particular, pyrolysis is currently considered as the most promising thermochemical process to produce energy from biomass (Tripathi et al., 2016). Pyrolysis consists in the thermal degradation of biomass in an oxygen-depleted atmosphere, leading to products often lumped into three groups: permanent gases, pyrolytic liquids, and a carbon enriched solid product (char or bio-char) (Cukierman et al., 2012). The liquid products, known as bio-oils, are of great interest because of their potential as bio-fuels, presenting, in general, the advantages of other liquid fuels, such as a low transport cost, high energetic density, and the feasibility of being employed in combined cycle gas turbine to generate electricity (Fan et al., 2011). However, the high water content of the bio-oils and the large amount of oxygenated compounds restrict their utilization and cause difficulties for their direct combustion (Jacobson et al., 2013). On the other hand, co-pyrolysis, namely thermal degradation of mixtures of two or more wastes in inert atmosphere, has been increasingly investigated in the last years in order to ensure availability of biomass sources and to take advantage of possible synergic effects. A few studies additionally report that co-pyrolysis of biomass with some biopolymers might represent an option to reduce water content of bio-oils and to increase their yield (Cornelissen


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et al., 2009; Abnisa and Wan Daud, 2014). Accordingly, thermal degradation of mixtures of cassava bagasse and lignocellulosic biomass could be an appealing possibility to employ these wastes for the sustainable generation of green energy and/or other value-added products. In this scenario, the present chapter examines the process of pyrolysis of cassava starch, as the major compound of dry cassava bagasse, and of mixtures of equal proportions of the starch with peanut hulls, as an abundant, representative lignocellulosic residue generated in the processing of this crop, which, as cassava, is also widely grown in tropic and subtropic regions. It focuses on yields and physicochemical properties of the three kinds of products obtained from assays for the pyrolysis of the starch, the peanut hulls, and of their mixtures (50 wt%) performed in a fixed-bed reactor for different process temperatures. Special emphasis is placed on possible synergetic effects which could lead to improve yield and/or properties of the bio-oils.

2. EXPERIMENTAL SECTION 2.1. Materials Cassava (Manihot esculenta) starch, labeled as CS, was provided by Bernesa S.A.C.I., Argentina. The cassava starch powder was processed by wet granulation, and then milled and screen-sieved. Fractions of particle diameter between 250 µm and 500 µm were reserved for the pyrolysis assays. In order to explore the copyrolysis of the starch with a lignocellulosic biomass, hulls from commercial peanut (Arachis hypogaea), abbreviated as PH, were employed. They were cleaned, milled, and screen-sieved. The same particle size as for the starch was employed for the experiments. A mixture in equal proportions of the cassava starch and the lignocellulosic biomass, designated as CS/PH, was prepared by physical mixing and utilized in the copyrolysis assays. Main properties of cassava starch and peanut hulls are displayed in Table 1. Proximate analysis of the samples was performed by thermogravimetric analysis (TA Instruments SDT Q600), according to American Society of Testing and Materials (ASTM) standards 5142. An automatic elemental analyzer (Carlo Erba model EA 1108) was used to determine elemental composition of the samples. Besides, amylose content of the starch was analyzed by standardized iodine colorimetry, according to ISO 6647-2:2007. The absorbance of the starch-iodine mixture was measured at 620 nm. Amylopectin content was determined by difference. To assess the content of main biopolymers constituting the hulls, the Van Soest analysis was executed.

2.2. Bench-Scale Pyrolysis Experiments A fixed bed reactor was utilized to carry out the pyrolysis/copyrolysis assays. The equipment mainly consisted of an AISI 316 stainless steel fixed bed reactor (2.5 cm I.D., 110 cm total length) with a special device which enabled to support a basket built in stainless steel mesh. The latter was used as a container of the samples. The reactor was externally heated by



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an electrical furnace driven by a Yokogawa UT350 temperature controller. The basket with the sample, constituting the solid fixed-bed, was centrally placed in the heated bottom zone of the reactor. A chromel-alumel thermocouple was located at the geometrical center of the basket to record the process temperature. At the reactor outlet, a series of flasks immersed in a cooling bath, using isopropyl alcohol at -10°C as solvent, enabled condensation and collection of the condensable volatiles generated with the thermal degradation course. Noncondensable vapors, after passing through the condensation system, were sampled periodically using Teflon gas bags for further analysis by gas chromatography, as detailed in the next subsection. Table 1. Chemical characteristics of the cassava starch (CS) and the peanut hulls (PH)

a

Characteristic / Sample Proximate Analysis (wt%)a Volatile matter Ash Fixed carbond Ultimate Analysis (wt%)b Carbon Hydrogen Nitrogen Oxygend Biopolymer composition (wt%) Amyloseb Amylopectinb,d Ligninc Cellulosec Hemicellulosec Dry basis. b Dry and ash-free basis. d Estimated by difference.

CS

PH

92.5 0.2 7.3

73.6 20.5 5.9

44.4 6.3 0.1 49.2

49.6 6.5 1.8 42.1

22.9 77.1

c

30.9 54.6 14.5 Neutral detergent fiber and ash-free basis.

To avoid partial combustion of the samples, all the installation was purged by flowing N2 (300 cm3 min-1) for 1 h. Afterwards, the heating system was connected and the desired temperature was set. Once the pre-established temperature was attained, the basket containing the sample was displaced to the heated zone of the reactor. After the holding time, heating was cut-off and the basket was immediately shifted towards the upper (non-heated) part of the reactor, keeping the N2 stream. Once at ambient temperature, the basket was removed from the reactor. The residual solid and the accumulated liquid products contained in the flasks were weighed to determine product yields. These products were then carefully stored in closed containers for further characterization. Percent yields were calculated as weight of product per total weight of raw sample. Gas yields were obtained by difference from overall mass balances. From preliminary experiments, it was found that the process temperature was the variable that had the greatest influence on the products yields. Also, it was determined that after 30 min the volatiles generation was negligible, indicating almost complete conversion. Other conditions, such as the particle size or the N2 flow rate, had a weak influence on the process


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yields. Therefore, the following pre-established operating conditions were selected to conduct the pyrolysis/copyrolysis assays: temperature = 400-600°C, N2 flow rate = 300 cm3 min-1, particle diameter = 250-500 µm; samples’ masses = 10-15 g, holding time = 30 min.

2.3. Characterization of the Pyrolysis Products Dichloromethane was used to extract the organic phase from the bio-oils (volume ratio solvent/bio-oil: 2:1). Elemental composition of the organic phase of the bio-oils was determined by ultimate analyses, as depicted above. Furthermore, their higher heating value (HHV) was also measured using a Parr 1341 oxygen bomb calorimeter. The samples’ pH was determined with an Orion 290A portable pH meter. Water content of the liquid samples was measured by volumetric Karl-Fischer titration (Methrom Herisau Karl Fisher Automat E 547) following ASTM E 203. Additionally, total phenol and sugar contents of the bio-oil were evaluated using the Folin-Ciocalteu and the phenol-sulphuric assays, respectively. Fourier transform infrared spectroscopy (FT-IR) analysis of the organic fractions of the bio-oils was carried out using a Perkin-Elmer IR Spectrum BXII spectrometer within the range 600-4000 cm-1 and an attenuated total reflection (ATR) device made of SeZn. Also, chemical compounds of the bio-oils were identified using a Trace GC Ultra chromatograph coupled with a Thermo Scientific EM/DSQ II mass spectrometer (GC-MS). The employed capillary column was a Rxi-5ms (length: 30 m; ID: 0.25 mm) and helium was used as carrier gas. Electron ionization (potential: 70 eV) was applied and the measured mass range varied from 30 to 500 m/z. Regarding the bio-chars, elemental analysis was performed, employing the aforementioned instrument and Fe3O4 as a combustion catalyst. FT-IR assays using the KBr pellet method were carried out using the aforementioned instrument. N2 adsorptiondesorption isotherms at -196°C were determined for the bio-chars with an automatic Micromeritics ASAP-2020 HV volumetric sorption analyzer. Before carrying out the measurements, the samples were outgassed at 120 ºC for two hours. Textural properties were assessed from the isotherms, according to conventional procedures depicted in detail in previous studies (Basso et al., 2005; Bonelli et al., 2007). Moreover, the bio-chars were examined by scanning electronic microscopy (SEM) in a Zeiss Supra 40 microscope equipped with a field emission gun. The samples were placed on an aluminium holder, supported on conductive carbon tape and sputter coated with Au-Pd. Non-condensable gases, after flowing through the condensation system, were sampled periodically using Teflon gas bags, and further analyzed with a Shimadzu GC-8 gas chromatograph supplied with a thermal conductivity detector and a concentric packed Altech CTR I column (6 ft x ¼ in). Argon as carrier gas and a column temperature of 25°C were employed. All the experiments were performed at least by triplicate and average values are informed. Differences between replicates were less than 5% in all cases.



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3. RESULTS AND DISCUSSION 3.1. Yields of the Pyrolysis/Copyrolysis Products

Yields [wt%]

Yields of the three kinds of pyrolysis products for the pyrolysis of CS at different temperatures are displayed in Figure 1. Bio-char yields show a decreasing trend with increasing temperatures attributable to a preponderance of volatilization reactions. The similar yields obtained at 500ºC and 600ºC suggest that volatilization is almost complete at 500ºC. This is in agreement with TGA studies reported for this biopolymer (Marques et al., 2006; Sin et al., 2011). Unlike pyrolysis of lignocellulosic biomass (Akhtar and Amin, 2012; Bridgwater, 2012; Kim et al., 2014), which shows the maximum bio-oil yield at approximately 500ºC, pyrolysis of CS leads to maximum bio-oil yields at lower temperatures (400ºC). This would be due to the fact that volatilization of this biopolymer is less important than the cracking of the pyrolysis vapours at higher temperatures, resulting in a higher gases production and in a decrease in bio-oil yields. 60 55 50 45 40 35 30 25 20 15 10 5

Bio-char Bio-oil Gases

350

400

450

500

550

600

650

Temperature [ºC] Figure 1. Effect of the process temperature on products yields for the pyrolysis of the cassava starch.

Figure 2 shows the yields for the three pyrolysis products obtained from the copyrolysis of CS/PH. It can be seen that the maximum bio-oil yield is achieved at a relatively higher temperature (500ºC) compared to that for the pyrolysis of CS. Volatilization of the solid is less complete for the mixture than for the pure starch, so the increase of temperature would promote vapor generation. At 600ºC, cracking reactions should be favored and, thus, gas yield is noticeably increased (Neves et al., 2011). Nevertheless, bio-oil yields are always lower than those obtained from the pyrolysis of CS. On the other hand, more bio-char is generated from the copyrolysis. This would be due to the more refractory nature of the hulls, owing to the presence of lignin which is thermally resistant to decompose (Bonelli et al., 2007; Yang et al., 2007; Collard and Blin, 2014).


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Luciano I. Gurevich Messina, Pablo R. Bonelli and Ana L. Cukierman 50

Yields [wt%]

45 40

Bio-char

35

Bio-oil

30

Gases

25 20 15 350

400

450

500

550

600

650

Temperature [ºC] Figure 2. Effect of the process temperature on products yields for the copyrolysis of the mixture of cassava starch and peanut hulls.

3.2. Properties of the Pyrolysis/Copyrolysis Products 3.2.1. Bio-Oils Elemental composition, HHV and pH of the bio-oils resulting from the pyrolysis of CS and the copyrolysis of CS/PH are displayed in Table 2. Bio-oils arising from the copyrolysis of the mixture have lower oxygen content than those generated by the pyrolysis of the starch. This could be probably related to the minor oxygen content of the hulls (Table 1). The presence of oxygenated compounds in bio-oils is undesirable since they augment their instability. They also contribute to diminish their miscibility with conventional fuels, such as fuel-oils, because of their high polarity (Lehto et al., 2014). In addition, the higher oxygen content of the bio-oils resulting from the pyrolysis and their lower carbon content result in a lower HHV for these liquids, with the exception of the bio-oils produced at 600ºC. This biooil presents more hydrogen and less nitrogen than the one generated by the copyrolysis of the mixture at 600ºC, which could lead to enhance its HHV. Regarding the nitrogen content, the bio-oils generated by the pyrolysis of the cassava starch showed a lower value, probably due to the low nitrogen content of the raw CS. Bio-oils with little content of nitrogen are more suitable as their further combustion would generate less NOx which is related to negative environmental impacts, such as acid rain (Cao et al., 2010). pH values for the bio-oils are in the typical range reported in the literature (Chiaramonti et al., 2007; Bridgewater, 2012). In particular, bio-oils have a great amount of formic and acetic acid (Oudenhoven et al., 2013). Besides, it has been reported that bio-oil acidity is mainly caused by decomposition of the different polysaccharides (cellulose, hemicellulose, amylose and amylopectin) (Collard and Blin, 2014). As the CS/PH mixture has lignin, which does not contribute significantly to generate carboxylic acids, this may be reflected in the higher pH value of the bio-oil arising from the mixture. Also, the pyrolysis of polysaccharides with a minor degree of polymerization would result in more carboxylic acids since the rupture of the glucose ring seems to be favored (Patwardhan et al., 2009). Amylose and amylopectin



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have a lower degree of polymerization than the one of cellulose and, consequently, thermal decomposition of the former biopolymers would produce more acids. Table 2. Elemental composition, higher heating value, and pH of the different bio-oils generated from the pyrolysis of cassava starch (CS) and the copyrolysis of the starch and the peanut hulls (CS/PH), at different temperatures CS (400ºC) Ultimate Analysis [wt%] a C 50.4 H 7.0 N 0.4 Ob 42.4 HHV [MJ/kg]a 22.4 pH 2.7 a Organic phase. b Estimated by difference. Bio-oil

CS (500ºC)

CS (600ºC)

CS/PH (400ºC)

CS/PH (500ºC)

CS/PH (600ºC)

49.5 7.0 0.0 43.5 21.0 2.7

51.7 7.5 0.2 40.7 23.5 2.8

54.1 7.4 0.7 37.8 23.8 3.0

53.5 7.8 1.7 37.0 24.1 2.9

53.2 6.2 2.9 37.7 21.9 2.8

Figure 3 displays the influence of the process temperature on the contents of water, sugars and phenols of the bio-oils. Bio-oils produced by the pyrolysis of CS result in less water content than those originated from the CS/PH mixture. This mixture is richer in ash which could catalyze ring scission reactions that also generate water (Fahmi et al., 2008; Mourant et al., 2011). It is also seen that the increase in process temperature leads to raise water content of the bio-oils derived from both the pyrolysis of the individual starch and the mixture. In accordance with other authors (Akhtar and Amin, 2012; Lin et al., 2013), this suggests that high temperatures promote dehydration reactions. The presence of water in the bio-oils contributes to reduce their energy density and also to decrease the values of adiabatic flame temperature and combustion rate. On the other hand, water lowers bio-oil viscosity (Chiaramonti et al., 2007; Lehto et al., 2014). The pyrolysis of CS generates more sugars than the copyrolysis of the CS/PH mixture. Since CS is almost completely constituted by amylopectin and amylose which are formed by glucose rings, the pyrolysis of cassava starch would produce diverse anhydrosugars, such as levoglucosan. Levoglucosan in bio-oil could be used for the synthesis of chiral polymers and to obtain fermentable carbohydrates in order to produce bio-ethanol (Bennett et al., 2009; Yang et al., 2013). Instead, the thermal degradation of hemicellulose and lignin that compose the hulls might generate other compounds such as furans and phenols (Lin et al., 2013; Collard and Blin, 2014). Furthermore, the minerals present in the hulls might act as catalyst of reactions that break down the glucose ring. Considering the process temperature effect, the sugar content of the bio-oils generated by the pyrolysis of individual cassava starch drops noticeably at the highest temperature investigated. This is probably due to ring scission reactions that are favored at high temperatures. The behavior, however, is not so clear in the case of the copyrolysis. Bio-oils generated from the copyrolysis present a greater amount of phenolic compounds because of the hulls’ lignin. Temperature has no noticeable effect on phenol content of the bio-oils. The phenolic compounds could be applied to produce phenol formaldehyde resins, glues, and intermediaries in the synthesis of different pharmaceutical products (Fele Žilnik and Jazbinšek, 2012).


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Luciano I. Gurevich Messina, Pablo R. Bonelli and Ana L. Cukierman 65

Water [wt%].

60 55

CS

50

CS/PH

45 40 35 350

400

450

500

550

600

650

Temperature [ºC]

(a)

Sugars [g/dm3]

25 20 CS

15

CS/PH 10 5 0 350

400

450

500

550

600

650

Temperature [ºC]

(b)

Phenols [g/dm 3]

25 20 CS

15

CS/PH

10 5 0 350

400

450

500

550

600

650

Temperature [ºC]

(c) Figure 3. Contents of water (a), sugars (b) and phenols (c) in the bio-oils generated from the pyrolysis of the cassava starch (CS) and the copyrolysis of the starch and the peanut hulls (CS/PH), at different temperatures. Sugars and phenols were determined in the aqueous phase.

Figure 4 presents the FT-IR spectra of the bio-oils produced from the pyrolysis of the cassava starch and from the copyrolysis of the starch and the peanut hulls at different process temperatures. All the samples exhibit similar spectra characterized by a strong absorption band at 3400 cm-1, corresponding to O-H stretching, absorption peaks at 3000 to 2800 cm-1, attributable to C-H stretching of methyl and methylene groups, and an overlap of weak and strong bands at the region from 1750 to 1000 cm-1 (Ben Hassen-Trabelsi et al., 2014). The absorption peak at 1750 cm-1, corresponding to carboxyl and carbonyl groups, is mainly due to the presence of carboxylic acids, ketones and aldehydes. Also, it can be seen that the



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absorption bands at 1595 cm-1 and at 1500 cm-1, that are assigned to the presence of aromatic rings, are more pronounced for the bio-oil arising from the mixture. This is expectable since lignin decomposition generates phenolic compounds. These peaks are noticeable in the bio-oil arising from the cassava starch pyrolysis as they contain furans which are also products of the thermal decomposition of polysaccharides. Furthermore, bands at 1080 to 1000 cm-1 corresponding to aromatic and aliphatic ethers are due to the presence of lignin products, such as syringol or guaiacol, and of sugars arising from the decomposition of starch and holocellulose.

Transmitance [%]

CS (600ºC)

CS (500ºC)

CS (400ºC) 3600

3100

2600 2100 Wavenumber [cm-1]

1600

1100

600

Transmitance [%]

(a)

CS/PH (600ºC)

CS/PH (500ºC)

CS/PH (400ºC) 3600

3100


1600

1100

600

(b) Figure 4. FT-IR spectra of the bio-oils produced from the pyrolysis of the cassava starch (a) and from the copyrolysis of the starch and the peanut hulls (b), at different temperatures.

In Figure 5 there are represented the total ion chromatograms of the bio-oils produced from the pyrolysis of CS and the copyrolysis of CS/PH mixture at a process temperature of 500ºC. The main compounds, identified by means of retention times (RT) and data of mass spectra found in the literature (Ohra-aho and Linnekoski, 2015; NIST Mass Spec Data Center, 2016) are listed in Table 3.


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Luciano I. Gurevich Messina, Pablo R. Bonelli and Ana L. Cukierman CS/PH

CS

5

10

15

20

25

30

35

40

45

Retention time [min]

Figure 5. Total ion chromatograms (TIC) for the bio-oils generated from the pyrolysis of cassava starch (CS) and the copyrolysis of the starch and peanut hulls (CS/PH). Process temperature = 500ºC.

Table 3. Main compounds detected in bio-oils by GC/MS analysis RT [min] 6.7 8.1 8.8 9.7 10.9 13.5 15.0 15.3 15.7 17.2 18.6 20.5 21.6 24.4 35.0 35.6 40.1

Compound phenol 2-hydroxy-3-methyl-2-cyclopenten-1-one p-cresol 2-methoxyphenol (guaiacol) 5-hydroxymethylfurfural 2-methoxy-4-methylphenol (creosol) catechol 1,4-anhydro--D-pyranose levoglucosenone 1,4:3,6-dianhydropyranose 2,6-dimethoxyphenol (syringol) vanillin 2-methoxy-4-propenylphenol (eugenol) 2-methoxy 4-propylphenol 2,6-dimethoxy 4-propylphenol levoglucosan 1,6--D-glucofuranose

As can be inferred from the TIC corresponding to the bio-oil arising from the pyrolysis of the mixture, the main products of the pyrolysis of holocellulose would be 2-hydroxy-3methyl-2-cyclopenten-1-one, 5-hydroxymethylfurfural, levoglucosan, and 1,6--Dglucofuranose. Regarding the lignin pyrolysis products, the most important peaks would correspond to compounds derived from coniferyl alcohol, such as guaiacol and eugenol, and from synapyl alcohol, such as syringol (Menon and Rao, 2012). The TIC for the bio-oil generated by the pyrolysis of CS is quite different since the peaks assignated to phenolic compounds, arising from lignin degradation, are not observable. In addition, besides the aforementioned compounds likely derived from holocellulose, other compounds are also detected: 1,4-anhydro--D-pyranose, levoglucosenone and 1,4:3,6dianhydropyranose. The two latter evolve from levoglucosan, thus suggesting that secondary



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reactions which partially transform this anhydrosugar have taken place. Although 1,4anhydro--D-pyranose is usually derived from hemicellulose, it has been detected among the pyrolysis products of corn starch (Patwardhan et al., 2009).

3.2.2. Bio-Chars Ash content, elemental composition, and high heating value of the bio-chars arising from the pyrolysis of the cassava starch and its copyrolysis with peanut hulls are displayed in Table 4. It can be seen that the ash content of the bio-chars derived from the copyrolysis is higher than those derived from the pyrolysis of the starch. This is in agreement with the lower ash content of the raw cassava starch (Table 1). On the other hand, the mixture which contains hulls possessing a higher ash content results in bio-chars with greater ash content. The process temperature has no noticeable effects on the ash content of the bio-chars derived from CS. By contrast, a slight increase in the ash content of the bio-chars arising from CS/PH mixtures with rising temperatures is found (Neves et al., 2011). Table 4. Ash content, elemental composition, and higher heating value of the different bio-chars generated from the pyrolysis of cassava starch (CS) and the copyrolysis of the starch with the peanut hulls (CS/PH), at different temperatures Bio-char

CS (400ºC)

CS (500ºC)

CS (600ºC)

Ash [wt %, dry 0.8 1.0 0.9 basis] Ultimate analysis [wt %, dry and ash-free basis] C 80.0 94.4 93.5 H 3.3 2.1 2.0 N 0.5 0.8 0.9 Oa 16.2 2.7 3.6 HHV [MJ/kg] 30.1 35.1 34.5 a Estimated by difference.

CS/PH (400ºC)

CS/PH (500ºC)

CS/PH (600ºC)

6.0

8.8

9.6

78.6 3.2 0.5 17.7 29.3

85.7 3.0 2.4 8.9 32.3

87.8 2.2 1.9 8.1 32.3

Regarding the elemental composition, pyrolysis of the cassava starch resulted in biochars with higher carbon content and lower oxygen content than those derived from the mixture. This could be due to the more refractory nature of the lignin present in the hulls, reducing the release of oxygenated volatile compounds. These differences in elemental composition lead to a higher value of the HHV of the bio-chars generated by the cassava starch pyrolysis. Nitrogen content of these bio-chars is also lower as the raw starch presents less elemental nitrogen than the hulls. Furthermore, at lower process temperatures, more oxygen is present in the bio-chars since the thermal degradation process is far from completion (Aysu y Küçuk, 2014). Nitrogen adsorption isotherms of the bio-chars generated from the pyrolysis of the cassava starch and the copyrolysis of the mixtures at different process temperatures are shown in Figure 6. Furthermore, the textural properties of these bio-chars are detailed in Table 5. As may be observed in Figure 6, the shape of the isotherms corresponding to all the samples present typical characteristics of isotherms type I according to IUPAC classification, indicating that all the solids mostly contain micropores (Rouquerol et al., 1999). The biochars generated at 400ºC and the one arising from cassava starch pyrolysis at 500ºC, do not


348


show pore development. However, the other three samples present a slight pore development, probably due to a partial gasification of the solids with steam or CO2 released in the starch pyrolysis (Raavendran and Ganesh, 1998). The derived bio-chars could be used as rough adsorbents, soil enhancer and CO2 capture agent in soil, or they could be activated to generate activated carbons by further steam or CO2 gasification (Cukierman y Bonelli, 2015). CS 500ºC

400ºC

600ºC

Adsorbed volume [cm3/g]

0.45

30

0.4

25

0.35 0.3

20

0.25

15

0.2 0.15

10

0.1

5

0.05 0

0

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Relative pressure (P/P0)

(a) 400ºC

CS/PH

500ºC

600ºC

Adsorbed volume [cm3/g]

7 6 5 4 3 2 1 0 0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Relative pressure (P/P0)

(b) Figure 6. Nitrogen adsorption isotherms (-196ºC) for the bio-chars generated from: (a) the pyrolysis of the cassava starch and, (b) the copyrolysis of the starch and the peanut hulls, at different temperatures.

Table 5. Textural properties of the differtent bio-chars produced from the pyrolysis of cassava starch (CS) and from the copyrolysis of the starch and the peanut hulls (PH) at different temperatures Bio-char SBET [m2/g] Vt [cm3/g] Rm [nm]

CS (400ºC) 0.3 0.001 2.5

CS (500ºC) 1.5 0.002 2.0

CS (600ºC) 81 0.04 1.0

CS/PH (400ºC) 2.8 0.003 2.1

CS/PH (500ºC) 17 0.008 0.9


CS/PH (600ºC) 16 0.01 1.2


349

Transmitance [%]

Figure 7 exhibits the FT-IR spectra of the bio-chars derived from the pyrolysis of cassava starch and the copyrolysis of the mixture at the different process temperatures. Unlike the biooils (Figure 4), it may be seen that the spectra of the bio-chars present few peaks indicating scarce presence of functional groups (Yin et al., 2013). All the spectra show absorption peaks at 1600 cm-1 (C=C stretching) and at 1370 cm-1 (CH3 deformation). Most of the bands assigned to oxygenated groups vary in intensity with the temperature. The O-H bond stretching absorption band, at 3350 cm-1, is only noticeable for the bio-oils generated at a process temperature of 400ºC. At higher process temperatures, the peak becomes weak. The band at 1730 cm-1, corresponding to C=O bond stretching of carbonyl and carboxyl groups, also vanishes with increasing temperatures. Interestingly, this peak is more pronounced for the bio-chars derived from pyrolysis of CS than for those arising from the copyrolysis of the CS/PH mixture. However, the intensity of the peak assigned to ether bonds, at approximately 1110 cm-1, does not change remarkably with the temperature, suggesting that these bonds are quite resistant to thermal decomposition.

CS (600ºC)

CS (500ºC)

CS (400ºC) 3600

3100


1600

1100

600

Transmitance [%]

(a)

CS/PH (600ºC)

CS/PH (500ºC)

CS/PH (400ºC) 3600

3100


1600

1100

600

(b) Figure 7. FT-IR spectra of the bio-chars produced from: (a) the pyrolysis of the cassava starch and, (b) the copyrolysis of the starch and the peanut hulls, at different temperatures.


350


SEM micrographs of both the bio-char generated by the pyrolysis of CS and the one derived from the copyrolysis of CS/PH at a process temperature of 500ºC are displayed in Figure 8. As seen in Figure 8.a., the bio-char shows large sheets with circular marks. These ones could be probably caused by the sudden decomposition of the spherical particles that formed the cassava starch. On the other hand, pyrolysis of the mixture resulted in a bio-char (Figure 8.b) which shares characteristics of the aforementioned bio-char and those of the solid product resulting from the pyrolysis of that kind of lignocellulosic biomasses (Bonelli et al., 2001). It looks like the sheets generated by the starch pyrolysis coated the partial fibrous structure of the bio-chars derived from the hulls.

Figure 8. SEM micrographs (2000x) of the bio-chars produced from: (a) the pyrolysis of the cassava starch and, (b) the copyrolysis of the starch and the peanut hulls at 500ºC.

3.2.3. Gases Main gases generated by the pyrolysis of cassava starch and its copyrolysis with peanut hulls were CO, CO2, CH4, and H2. The presence of C2H4 and C2H6 has not been detected in this work with the instrument employed, even though they have been reported by some other authors in the literature (Horne and Williams, 1996; Couhert et al., 2009). Moles of each gas produced at a certain time are calculated according to: t



G i  C i Q dt

(1)

0

being Gi, the total generated moles of the generic gaseous species i, Ci, the molar concentration of the gaseous species i, and Q, the total volumetric flow of gas. In Figure 9 there are represented the generated moles for each gas over the reaction time for the pyrolysis of cassava starch and its copyrolysis with the peanut hulls, at 500ºC, respectively. Generation of CO and CO2 is mainly attributed to the thermal decomposition of the polysaccharides. The main source of the former would be carbonyl groups, while the latter may be associated with decarboxylation reactions. Thus, CO should be mainly generated by the cellulose pyrolysis, while CO2 may be principally derived from degradation of hemicellulose (Yang et al., 2007). The occurrence of decarboxylation reactions is linked to the polymerization degree and the cristallinity of the solids employed (Collard and Blin,



351

2014). As starch has a polymerization degree similar to hemicellulose and its cristallinity is lower than that of cellulose, these characteristics could explain the major CO generation. On the other hand, CH4 and H2 are mainly generated by lignin pyrolysis. Therefore, the copyrolysis of CS/PH produces slightly more of these two gases. CS

mol of gases / kg sample

7 6

CH

5

4

H

4

2 CO 2

3

CO

2 1 0

0

5

10

20

25

30

CS/PH

5

mol of gases / kg sample

15 t [min]

4 CH

H

3

4 2

CO

2

CO

2

1

0 0

5

10

15 t [min]

20

25

30

Figure 9. Production of main gases arising from the pyrolysis of the cassava starch (CS) and from the copyrolysis of the starch and the peanut hulls at 500ºC.

In addition, the HHV of the gas stream is calculated taking into account the total moles produced of each species per unit of sample mass and the heat of combustion of each species, according to the following equation:

PCS [MJ/kg]  0.802G CH4  0.286G H2  0.283G CO

(2)

The calculated HHV values are 0.9 MJ/kg for the gases generated by the pyrolysis of CS, and 1.5 MJ/kg for the gases generated by the copyrolysis of CS/PH. The combustion of these


352


gases could supply part of the heat necessary for the development of the processes (Bridgwater, 2012).

CONCLUSION The feasibility of the thermochemical conversion of cassava bagasse was investigated, exploring the pyrolysis process of its main constituent (cassava starch) and copyrolysis of the starch with peanut hulls, in equal proportions, at temperatures from 400ºC to 600ºC. Yields and characteristics of the three kinds of pyrolysis products (bio-oils, bio-chars and gases) were determined. Temperature had a considerable effect on the products yields of both the pyrolysis of cassava starch and the copyrolysis with peanut hulls. In both cases the rise of temperature led to an increase of gases generation and to a reduction of the bio-char produced. The maximum bio-oil generation took place at different temperatures for the starch and the mixture: while the yield for the pyrolysis of cassava starch occurred at 400ºC, the maximum yield of bio-oil for the copyrolysis happened at 500ºC. Furthermore, different maximum liquid yields were achieved, being 57 wt% for the former, and 49 wt% for the latter. Over the whole range of temperatures investigated, the pyrolysis of cassava starch resulted in a greater bio-oil generation and yielded less bio-char than the copyrolysis. Copyrolysis of the starch and the hulls led to bio-oils with a higher carbon content and a lower oxygen content, which would improve their stability and miscibility with conventional fuels. Also, in most cases, the employment of the mixture contributed to raise the high heating value of the bio-oils attaining values up to ~24 MJ/kg. In turn, pyrolysis of the starch yielded bio-oils with less nitrogen content, a favourable characteristic in terms of reducing NOx emissions in case of further combustion. Regarding water generation, the pyrolyisis of starch redounded in bio-oil quality as they presented less water. The increase of process temperature augmented water concentration in the bio-oils. Despite exhibiting almost the same functional groups, the bio-oils arising from the pyrolysis of cassava starch were different to the ones originated from the copyrolysis. Other derivatives from the constituent polysaccharides and no phenolic compounds were detected. The bio-chars generated from the pyrolysis of the starch presented less ash content than those arising from the copyrolysis, becoming more suitable for combustion in steam boilers as less fouling would occur. Carbon content of the bio-chars produced by the pyrolysis of the starch was higher, leading to greater high heating value (up to 35 MJ/kg). These bio-chars also showed less nitrogen content. In agreement with the observed FT-IR spectra, oxygen content of the bio-chars decreased with increasing temperature. The bio-chars arising from the highest process temperature presented an incipient pore development. Accordingly, they could be employed as rough adsorbents or be further upgraded to activated carbons. The pyrolysis of cassava starch and copyrolysis with peanut hulls generated gaseous compounds, principally CO2, CO, CH4 and H2. The presence of the hulls in the mixture allowed a major generation of the three latter, leading to increase the high heating value of the gaseous stream. The gases could aid to the energy sustainability of the pyrolysis/copyrolysis process. Overall, present results contribute to the understanding of the thermochemical



353

conversion of residues and mixtures, such as cassava bagasse and peanut hulls, into green energy vectors.

ACKNOWLEDGMENT The authors gratefully acknowledge Agencia Nacional de Promoción Científica y Tecnológica – Fondo para la Investigación Científica y Tecnológica (ANPCYT-FONCYT), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), and Universidad de Buenos Aires (UBA) from Argentina, for financial support.

REFERENCES Abnisa, F., Wan Daud, W.M.A. 2014. A review on co-pyrolysis of biomass: An optional technique to obtain a high-grade pyrolysis oil. Energy Conversion and Management 87, 71–85. Akhtar, J., Saidina Amin, N. 2012. A review on operating parameters for optimum liquid oil yield in biomass pyrolysis. Renewable and Sustainable Energy Reviews 16, 5101–5109. Aysu, T., Küçük, M.M. 2014. Biomass pyrolysis in a fixed-bed reactor: Effects of pyrolysis parameters on product yields and characterization of products. Energy 64, 1002–1025. Basso, M.C., Cerrella, E.G., Buonomo, E.L., Bonelli, P.R., Cukierman, A.L. 2005. Thermochemical conversion of Arundo donax into useful solid products. Energy Sources, 27, 1429–1438. Ben Hassen-Trabelsi, A., Kraiem, T., Naoui, S., Belayouni, H. 2014. Pyrolysis of waste animal fats in a fixed-bed reactor: Production and characterization of bio-oil and biochar. Waste Management 34, 210–218. Bennett, N.M., Helle, S.S., Duff, S.J.B. 2009. Extraction and hydrolysis of levoglucosan from pyrolysis oil. Bioresource Technology 100, 6059–6063. Bonelli, P.R., Della Rocca, P.A., Cerrella, E.G., Cukierman, A.L. 2001. Effect of pyrolysis temperature on composition, surface properties and thermal degradation rates of Brazil Nut shells. Bioresource Technology 76, 15–22. Bonelli, P.R., Buonomo, E.L., Cukierman, A.L. 2007. Pyrolysis of sugarcane bagasse and copyrolysis with an Argentinean subbituminous coal. Energy Sources. Part A: Recovery, Utilization, and Environmental Effects, 29, 731–740. Bridgwater, A.V. 2012. Review of fast pyrolysis of biomass and product upgrading. Biomass and Bioenergy 38, 68–94. Cao, J.-P., Zhao, X.-Y., Morishita, K., Wei, X.-Y., Takarada, T. 2010. Fractionation and identification of organic nitrogen species from bio-oil produced by fast pyrolysis of sewage sludge. Bioresource Technology 101, 7648–7652. Chiaramonti, D., Oasmaa, A., Solantausta, Y. 2007. Power generation using fast pyrolysis liquids from biomass. Renewable and Sustainable Energy Reviews 11, 1056–1086. Cherubini, F., Strømann, A.H. 2011. Principles of Biorefining. In “Biofuels: Alternative Feedstocks & Conversion Processes” Editors: A. Pandey, C. Larroche, S.C. Ricke, C.-G.


354


Dussap, E. Gnansounou., Academic Press, Amsterdam, The Netherlands, Chapter 1, 3– 24. Collard, F.-X., Blin, J. 2014. A review on pyrolysis of biomass constituents: Mechanisms and composition of the products obtained from the conversion of cellulose, hemicelluloses and lignin. Renewable and Sustainable Energy Reviews 38, 594–608. Cornelissen, T., Jans, M., Stals, M., Kuppens, T., Thewys, T., Janssens, G.K., Pastijn, H., Yperman, J., Reggers, G., Schreurs, S., Carleer, R. 2009. Flash co-pyrolysis of biomass: The influence of biopolymers. Journal of Analytical and Applied Pyrolysis 85, 87–97. Couhert, C., Commandre, J.-M., Salvador, S. 2009. Is it possible to predict gas yields of any biomass after rapid pyrolysis at high temperature from its composition in cellulose, hemicellulose and lignin? Fuel 88, 408–417. Cukierman, A.L., Nunell, G.V., Fernández, M.E., De Celis, J., Kim, M.R., Gurevich Messina, L., Bonelli P.R. 2012. Thermochemical processing of wood from invasive arboreal species for sustainable bioenergy generation and activated carbons production. In “Invasive Species: Threats, Ecological Impact and Control Methods.” Editors J. J. Blanco and A. Fernandes. Nova Science Publishers Inc., N.Y., USA. Chapter 1, 1–46. Cukierman, A.L., Bonelli, P.R. 2015. Potentialities of biochars from different biomasses for climate change abatement by carbon capture and soil amelioration. In “Advances in Environmental Research” Editor J.A. Daniels. Nova Science Publishers Inc., N.Y., USA. Volume 44, 57–79. Debiagi, F., Marim, B.M., Mali, S. 2015. Properties of cassava bagasse and polyvinyl alcohol biodegradable foams. Journal of Polymers and the Environment 23, 269–276. Fahmi, R., Bridgwater, A.V., Donnison, I., Yates, N., Jones, J.M. 2008. The effect of lignin and inorganic species in biomass on pyrolysis oil yields, quality and stability. Fuel 87, 1230–1240. Fan, J., Kalnes, T.N., Alward, M., Klinger, J., Sadehvandi, A., Shonnard, D.R. 2011. Life cycle assessment of electricity generation using fast pyrolysis bio-oil. Renewable Energy 36, 632–641. Fele Žilnik, L., Jazbinšek, A. 2012. Recovery of renewable phenolic fraction from pyrolysis oil. Separation and Purification Technology 86, 157–170. Frau, C., Ferrara, F., Orsini, A., Pettinau, A. 2015. Characterization of several kinds of coal and biomass for pyrolysis and gasification. Fuel 152, 138–145. Horne, P. A., Williams, P.T. 1996. Influence of temperature on the products from the flash pyrolysis of biomass. Fuel 75, 1051–1059. Jacobson, K., Maheria, K.C., Kumar Dalai, A. 2013. Bio-oil valorization: A review. Renewable and Sustainable Energy Reviews 23, 91–106. Jyothi, A. N., Sasikiran, K., Nambisan, B., Balagopalan, C. 2005. Optimisation of glutamic acid production from cassava starch factory residues using Brevibacterium divaricatum. Process Biochemistry 40, 3576–3579. Kim, T.-S., Oh, S., Kim, J.-Y., Choi, I.-G., Choi, J.W. 2014. Study on the hydrodeoxygenative upgrading of crude bio-oil produced from woody biomass by fast pyrolysis. Energy 68, 437–443. Lehto, J., Oasmaa, A., Solantausta, Y., Kytö, M., Chiaramonti, D. 2014. Review of fuel oil quality and combustion of fast pyrolysis bio-oils from lignocellulosic biomass. Applied Energy 116, 178–190.



355

Lin, T., Goos, E., Riedel, U. 2013. A sectional approach for biomass: Modelling the pyrolysis of cellulose. Fuel Processing Technology 115, 246–253. Long, H., Li, X., Wang, H., Jia, J., 2013. Biomass resources and their bioenergy potential estimation: A review. Renewable and Sustainable Energy Reviews 26, 344–352. Marques, P.T., Lima, A.M.F., Bianco, G., Laurindo, J.B., Borsali, R., Le Meins, J.-F., Soldi, V. 2006. Thermal properties and stability of cassava starch films cross-linked with tetraethylene glycol diacrylate. Polymer Degradation and Stability 91, 726–732. Menon, V., Rao, M. 2012. Trends in bioconversion of lignocellulose: Biofuels, platform chemicals & biorefinery concept. Progress in Energy and Combustion Science 38, 522– 550. Mourant, D., Wang, Z., He, M., Wang, X.S., Garcia-Perez, M., Ling, K., Li, C.-Z. 2011. Mallee wood fast pyrolysis: Effects of alkali and alkaline earth metallic species on the yield and composition of bio-oil. Fuel 90, 2915–2922. Neves, D., Thunman, H., Matos, A., Tarelho, L., Gómez-Barea, A. 2011. Characterization and prediction of biomass pyrolysis products. Progress in Energy and Combustion Science 37, 611–630. NIST Chemistry WebBook. 2016. http://webbook.nist.gov/chemistry. Ohra-aho, T., Linnekoski, J. 2015. Catalytic pyrolysis of lignin by using analytical pyrolysisGC–MS. Journal of Analytical and Applied Pyrolysis 113, 186–192. Oudenhoven, S.R.G., Westerhof, R.J.M., Aldenkamp, N., Brilman, D.W.F., Kersten, S.R. A. 2013. Demineralization of wood using wood-derived acid: Towards a selective pyrolysis process for fuel and chemicals production. Journal of Analytical and Applied Pyrolysis 103, 112–118. Pandey, A., Soccol, C.R., Nigam, P., Soccol, V.T., Vandenberghe, L.P., Mohan, R. 2000. Biotechnological potential of agro-industrial residues. II: cassava bagasse. Bioresource Technology 74, 81–87. Pandey, A., Larroche, C., Ricke, S.C., Dussap, C.-G., Gnansounou., E. 2011. Biofuels: Alternative Feedstocks & Conversion Processes. Academic Press, Amsterdam, The Netherlands. Patwardhan, P.R. Satrio, J.A., Brown, R.C., Shanks, B.H. 2009. Product distribution from fast pyrolysis of glucose-based carbohydrates. Journal of Analytical and Applied Pyrolysis 86, 323–330. Raveendran, K., Ganesh, A. 1998. Adsorption characteristics and pore-developement of biomass- pyrolysis char. Fuel 77, 769–781. Rouquerol, F., Rouquerol, J., Sing, K. 1999. Adsorption by powders and porous solids. Principles, methodology and applications. Academic Press Ed., Londres. Sin, L.T., Rahman, W. A.W.A., Rahmat, A. R., Mokhtar, M. 2011. Determination of thermal stability and activation energy of polyvinyl alcohol–cassava starch blends. Carbohydrate Polymers 83, 303–305. Tripathi, M., Sahu, J.N., Ganesan, P. 2016. Effect of process parameters on production of biochar from biomass waste through pyrolysis: A review. Renewable and Sustainable Energy Reviews 55, 467–481. Ullah, K., Kumar Sharma, V., Dhingra, S., Braccio, G., Ahmad, M., Sofia, S. 2015. Assessing the lignocellulosic biomass resources potential in developing countries: A critical review. Renewable and Sustainable Energy Reviews 51, 682–698.


356


Yang, H., Yan, R., Chen, H., Lee, D.H., Zheng, C. 2007. Characteristics of hemicellulose, cellulose and lignin pyrolysis. Fuel 86, 1781–1788. Yang, Z., Liu, X., Yang, Z., Zhuang, G., Bai, Z., Zhang, H., Guo, Y. 2013. Preparation and formation mechanism of levoglucosan from starch using a tubular furnace pyrolysis reactor. Journal of Analytical and Applied Pyrolysis 102, 83–88. Yin, R., Liu, R., Mei, Y., Fei, W., Sun, X. 2013. Characterization of bio-oil and bio-char obtained from sweet sorghum bagasse fast pyrolysis with fractional condensers. Fuel 112, 96–104. Zhang, L., Xu, C., Champagne, P. 2010. Overview of recent advances in thermo-chemical conversion of biomass. Energy Conversion and Management 51, 969–982. Zhang, M., Xie, L., Yin, Z., Khanal, S.K., Zhou, Q. 2016. Biorefinery approach for cassavabased industrial wastes: Current status and opportunities. Bioresource Technology 215, 50–62.




Chapter 18

TREND IN THE TRADE OF CASSAVA PRODUCTS IN THE COASTAL, EASTERN AND WESTERN REGIONS OF KENYA C. M. Githunguri1, , M. Gatheru2 and S. M. Ragwa2 *

1


ABSTRACT The potential to increase cassava products utilization is enormous if the available recipe range can be increased. A marketing survey was conducted in Mombasa, Nairobi and Busia urban centres. In Mombasa and Nairobi, marketing of cassava products was done daily. In Busia, daily marketing accounted for 22% while 78% was through a local market that opens twice a week. In Mombasa, 100% of cassava products were mainly sold at the main market (Kongowea). In Nairobi, 94% of respondents sold their products in local markets (Gikomba and Kibera) and 6% to hotels. In Busia, 50% sold their products at the main market and 50% in secondary markets. Sale of cassava products in Mombasa, Busia and Nairobi dates as early as 1956, 1962 and 1987, respectively. In Mombasa, cassava crisps and fried fresh cassava constituted 8% and fresh roots 92%. In Nairobi, boiled cassava constituted 6%, flour 25% and dried chips 69% of products being traded in. In Busia cassava flour constituted 33% and dried chips (for milling) 67% of the products sold. In Mombasa, the average price of a fresh root was 13 shillings during scarcity and 8 shillings during abundance. In Nairobi, a 2-kg tin (gorogoro) was sold at 69 and 55 shillings during scarcity and abundance, respectively. In Busia, the average price of a gorogoro was 35 and 31 shillings during scarcity and abundance, respectively. In Mombasa, the majority of those marketing cassava products were males while in Nairobi and Busia females dominated. The main products sold in Mombasa were crisps, fried chips, and fresh roots. In Nairobi, the main products were boiled cassava, flour and dry chips. In Busia, flour and dried chips were the main products. In Mombasa the major customers were final consumers, retailers and processors. In Nairobi major customers *

Email: [email protected], Cellphone: +254 726959592.


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C. M. Githunguri, M. Gatheru and S. M. Ragwa were final consumers, wholesalers, retailers and millers. In Busia customers were final consumers, wholesalers, retailers and processors. In Mombasa and Busia the principal suppliers of cassava products were both male and female while in Nairobi it was women. One of the main supply constraint reported was lack of cassava during scarcity. Competition from maize was cited in Mombasa and Nairobi. Costly transport was reported in Mombasa and Busia. In Mombasa, lack of credit was also cited. In Busia, other important constraints recorded were lack of sorghum and finger millet for blending cassava, and unfavourable weather for drying of cassava chips.

INTRODUCTION Cassava is a major food security crop across sub-Saharan Africa. In Kenya cassava is grown in over 61,000 ha with an annual production of about 738,000 tons (MoA, 2009; GoK, 2010). Kenya produced approximately 800,000 metric tons of cassava valued at 3.8 billion K. Shs in 2006 and has the potential to produce more than 2 million metric tonnes per year (MoA, 2011). Cassava is produced mainly in western, Coast and eastern Kenya while production in the other regions is relatively low. Cassava is a highly drought tolerant crop and as such there is high potential for its increased production in the arid and semi-arid lands, which comprise about 80% of Kenyan land mass. Though cassava is considered a food security crop in the sub-Saharan Africa, its production in Kenya is low compared to other crops like maize, beans, and sorghum. Its consumption is low especially in the central region of Kenya where it is considered a poor man’s crop and is usually consumed during periods of food scarcity. Despite its high production in the coastal and western regions of Kenya, utilization is limited to human consumption. Utilization in Kenya is limited to roasting and boiling of fresh roots for consumption in most growing areas. However, in Nyanza and Western provinces of Kenya, roots are also peeled, chopped into small pieces (cassava chips), dried and milled into flour for ugali. In order to promote its production, which has been decreasing in recent years, there, is need to explore and identify other uses of cassava (MoA, 2011). It is estimated that Africa produces about 42% of the total tropical world production of the crop (FAO, 1990). Cassava can grow in marginal lands, requires low inputs, and is tolerant to pests and drought (Githunguri et al., 1998; Nweke et al., 2002; Githunguri et al. 2006a). Despite its great potential as a food security and income generation crop among rural poor in marginal lands, its utilization remains low in Kenya. In addition, it can be safely left in the ground for a period of 7 to 24 months after planting and then harvested as needed. Cassava is the second most important food root crop after Irish potato in Kenya. However due to its narrow production base it is ranked number 36 out of 50 in KARI’s 1991 priority setting exercise (KARI, 1995). Available statistics on cassava production in the country show a slow but steady increase in production. Cassava production in the country is concentrated in three main regions; Coastal, Central and Western region. Western and Coastal regions are the main cassava producing areas, producing over 80% of the recorded cassava output in the country (MoA, 1999). The importance of cassava as a food and cash crop in central Kenya is however increasing. The potential to increase cassava products utilization is enormous if the available recipe range can be increased (Githunguri, 1995). It has also been demonstrated that it is very important to present cassava to urban consumers in attractive forms at affordable prices,


Trend in the Trade of Cassava Products …

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which are competitive to those of cereals (Nweke et al., 2002; International Fertilizer Development Center (IFDC), 2012). The International Institute of Tropical Agriculture (IITA) has officially recognized cassava as a new cash commodity, which will help raise foreign exchange and be a vital food source throughout Africa. The Amsterdam-based Common Fund for Commodities has also recognized cassava as an internationally tradable commodity (Nweke, 2002). The Intergovernmental Group on Grains has adopted cassava as a commodity (Githunguri et al., 2006b; Nweke, 2002). Globally, the traditional use of cassava is changing from primarily human consumption to processing industrialized products (MoA, 2011). In Asia, cassava is a diversified fully commercial crop. Here, its roots are converted into an array of products - human food from the roots, and starch, flour, ethanol and animal feed for industry. In Latin America and the Caribbean, traditional processing and markets have now been dominated by industrial processing. In Brazil for example, starch and ethanol production from cassava is on the increase. The Far East, especially China is emerging as a major world market for starch and pellets. Europe, Latin America and Asia have seen the most cassava consumption increase using animal feed for their industries. Africa however continues to lag behind with 90% of its cassava still being consumed as human food (MoA, 2011). Marketing is still a major challenge for the cassava sub-sector especially for the dried chips. Cassava marketing in the country is undeveloped and like in most food crops not efficiently organized. Cassava producers sell fresh roots at farm gate or at the nearby markets. Buyers are mainly middlemen, local traders or neighbours who do not have cassava on their farms. The middlemen and local traders in turn sell the fresh roots in local markets directly to consumers or other retailers. Formal price/market information on cassava does not exist unlike other major food crops whose prices are provided through the print and electronic media. Cassava growers and traders get information on cassava prices through inquiry and previous market conditions (Makokha and Tunje, 2000). The demand for processed cassava products in Kenya has not been well documented. Some import and export statistics of cassava starch however point to a possibility of a potential cassava starch market in the country (Wambugu and Mungai, 2000). Import export trade for cassava products in Kenya is only documented for cassava starch. The level of trade is however, very small and there is scope for expansion. Exports of cassava starch from Kenya have been mainly to Tanzania, Uganda, Portugal, and South Africa. Unconfirmed reports also indicated informal trade of cassava between Kenya and Uganda along the common border. There are no organized marketing associations either by farmers or traders. Marketing is mainly done by producers as individuals in nearby markets or sold to middlemen who then transport cassava for sale in local or district market centres. According to Githunguri et al. (2008a, 2008b, 2009a and 2009b), the quality characteristics mostly preferred for cassava products are white colour, fibre-free, good taste, high dry matter content, medium size, good texture and low moisture content. Processing of cassava fresh roots would help to increase shelf-life, reduce transportation problems and costs, and remove cyanogens. It also improves palatability, adds value and extends market especially to medium income urban consumers (Nweke et al., 2002). Whether cassava can be relied upon as a low cost staple food In urban centres and a source of steady real income for rural households will to a larger extent depend on how well it can be processed into safe forms and on how far it can be presented to urban consumers in an attractive form at prices which are competitive to those of cereals. In some large cassava producing countries like Nigeria, the market for some processed


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products is highly limited to low income groups, while other forms of cassava, e.g., gari have a significant market value for middle and high income consumers. How far the market for cassava may be expended would therefore depend largely on the degree to which the quality of the various processed products can be improved to make them attractive to potential consumers without significant increase in processing costs. Cassava processing is therefore an important factor in marketing because an introduction of improved post-harvest handling facilities could lead to a substantial increase in proportion of cassava marketed (Nweke et al., 2002). Improved processing hygiene and packaging could improve their shelf life and make them attractive and acceptable in a wider market. Cassava products processing and utilization is done mainly at the subsistence level (Kadere, 2002). At the coastal region, it is men who roast and sell cassava crisps. In both Eastern and Western Kenya, women dominate homebased processing while service processing like milling is male dominated. As processing becomes mechanized men tend to play a leading role. The few home-based processors sell their products directly to consumers or retailers. Tapioca Ltd. in Mazeras is the only factory that employs modern technology to produce cassava flour, starch and glue. Most cassava processing technologies are labour-based facing serious limitations in areas with labour shortages (Mbwika, 2002). Rudimental processing technologies like over reliance on sun-dried methods are rendered impossible during the rainy season. Peeling of cassava roots manually using a knife is time consuming, laborious, difficult to ensure quality control and wasteful. The fine particles of cassava flour render current milling technologies wasteful. There is need to identify appropriate storage and processing technologies that are cheap, have low losses, improve shelf life and guarantees quality products. Efforts should be made to involve the food processing industry in making ready to eat cassava products available in supermarkets and retail outlets. Due to the enormous potential demand for cassava by the feeds, pharmaceutical, food, paper printing and brewing industries there is need to involve them in the research and development of this sub-sector. The Kenya Bureau of Standards needs to develop cassava products standards so that several industrial concerns can accept them as important inputs. Cassava utilization can be improved by availing cassava marketing information in audio and print media. Marketing is still a major challenge for the cassava sub-sector especially for the dried chips. Cassava marketing in the country is undeveloped and like in most food crops not efficiently organized. Cassava producers sell fresh roots at farm gate or at the nearby markets. Buyers are mainly middlemen, local traders or neighbours who do not have cassava on their farms. The middlemen and local traders in turn sell the fresh roots in local markets directly to consumers or other retailers. Import export trade for cassava products in Kenya is only documented for cassava starch. The level of trade is however, very small and there is scope for expansion. Exports of cassava starch from Kenya have been mainly to Tanzania, Uganda, Portugal, and South Africa. Unconfirmed reports also indicated informal trade of cassava between Kenya and Uganda along the common border. There are no organized marketing associations either by farmers or traders. Marketing is mainly done by producers as individuals in nearby markets or sold to middlemen who then transport for sell to local or district market centers. There is need to carry out a comprehensive marketing study on cassava and support its marketing in Kenya if cassava is to play its rightful role in the food security and industrialization (KARI, 1995).



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Markets refer to types of places where people shop e.g., (store, supermarket) and not a location where people shop and contrary to popular belief marketing begins from production all the way to the final consumer. Policy objectives of many governments are increasingly geared towards commercialization and thus developed markets are important for commercialization justifying the case for processing. This is due to the simple reason that unprocessed output or limited utilization option results in underutilization after harvest and thus processing will increase usable physical volume and economic value of existing production (Scott 1995). Identifying markets for improved or new processed products important critical in efforts to increase incomes, generate employment and in reducing postharvest losses. Although a wide variety of product market options maybe available, identification of the few with the greatest commercial promise requires a systemic appraisal which this study was designed to do for the cassava sub-sector in Kenya. Thus the broad goal and objective of this study was to evaluate the status and the market potential for cassava and its processed products while the specific objectives were: i. ii. iii. iv. v. vi.

to determine supply and demand situation of cassava and cassava products in cassava grown regions of Kenya; to characterize cassava producers (farmers) and determine marketing constraints and opportunities in the cassava sub-sector; to determine the status of cassava processing and evaluate market potential of cassava processed products in Kenya; to determine the status of the cassava market and marketability of cassava products in Kenya; to assess the comparative commercial potential of alternative product markets; and to estimate the most important processed products sold by volume and value.

STUDY METHODOLOGY The study was conducted in the coastal (Mombasa), eastern (Nairobi) and western (Busia) regions of Kenya where only the major markets were visited and cassava traders interviewed randomly. The classical theory of statistical inference based on the properties of samples and sampling distributions was used (Greene, 2000). In this kind of study it is not possible to predetermine the sample size. Randomly selected cassava traders were interviewed using a structured questionnaire. Data collected included information on traders’ characteristics, business activities, storage of cassava and cassava-based products, demand and supply characteristics. The data collected were analyzed using the Statistical Package for Social Sciences (SPSS).

RESULTS AND DISCUSSION Market Characteristics Market characteristics in the three study areas are shown in Tables 1 and 2. In Mombasa and Nairobi, marketing of cassava and cassava-based products was done on a daily basis


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(Table 1). In Busia, daily marketing accounted for 22% while 78% of marketing was done through a local market that opens twice a week. Figures 1 and 2 shows the retailing of fresh cassava tuberous roots at Kongowea Market, Mombasa.

Figure 1. Farmers vend fresh cassava tubers at Kongowea Market, Mombasa.

Figure 2. A trader being interviewed by a market analysts about his business at Kongowea, Mombasa.

Table 1. Type of market by region

Region

Daily

Mombasa Nairobi Busia

100 100 22.2

Market type Other % respondents 0 0 77.8



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Table 2. Market category for cassava and cassava based products

Region

Main market

Mombasa Nairobi Busia

100 93.8 50

Market category Secondary market % respondents 0 0 50

Hotel 0 6.2 0

In Mombasa, 100% of respondents reported that cassava and cassava-based products were sold at the main market (Kongowea). In Nairobi, 94% of respondents sold their products in local markets (Gikomba and Kibera) while about 6% sold their products to hotels. In Busia, 50% of respondents sold their products at the main market while 50% sold in secondary markets.

Figure 3. Processed cassava crisps at Mama Ngina Drive, Mombasa.

Figure 4. Cassava chips (fermented and sun-dried) ready to be mixed with other cereals for milling into flour.


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C. M. Githunguri, M. Gatheru and S. M. Ragwa Table 3. Characteristics of traders of cassava and cassava-based products

Characteristic

Age of trader (yr) Trading experience (yr) Gender of trader Male Female Origin of trader Native Migrant Education level None Primary Secondary Post-secondary Own a store Yes No Business category Wholesaler Whole sale & retail Retail Own the business Yes No Sell other products Yes No Other products sold Grains (cereals etc) Other root crops Vegetables Animal products Others

Mombasa Mean Standard deviation 42 17 19 13

Region Nairobi Busia Mean Standard Mean Standard deviation deviation 43 13 44 13 7 6 12 15 Percent of respondents

58 42

19 81

22 78

75 25

25 75

67 33

25 50 25 0

25 25 50 0

44 33 23 0

8 92

73 27

33 67

8 17 75

19 25 56

0 22 78

100 0

88 12

100 0

25 75

100 0

78 22

0 33 0 0 67

87 0 0 0 13

85 0 15 0 0

CHARACTERISTICS OF CASSAVA TRADERS Characteristics of traders of cassava and cassava-based products are shown in Table 3. Figure 3 shows sale of cassava crisps at Mama Ngina Drive, Mombasa. On the other hand Figure 4 shows cassava chips (fermented and sun-dried) ready to be mixed with other cereals for milling into flour in Busia in western Kenya. In Mombasa, cassava wholesalers constitute



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8%; wholesalers/retailers 17% and retailers 75%. In Nairobi, 19% of respondents were wholesalers, 25% were wholesalers/retailers while 56% were retailers. In Busia 22% of respondents were both wholesalers and retailers while 78% were retailers. In Mombasa, the majority (58%) of those marketing cassava and cassava-based products were males while in Nairobi and Busia the business was dominated by females (Figure 5). The origin of cassava traders was as follows; in Mombasa (75%) were natives and 25% were migrants while in Busia (67%) were natives and 33% migrants. In Nairobi 75% of the traders were migrants. The average age of respondents was 42 years in Mombasa, 43 years in Nairobi and 44 years in Busia. The minimum (20 years) and maximum (85 years) age of respondents was recorded in Mombasa. The average number of years in cassava trading was highest (19 years) in Mombasa while Nairobi recorded the lowest (7 years). The average number of years in cassava trading was 12 years in Busia. Busia had the highest (44%) percentage of traders without formal education while Nairobi region recorded the highest (50%) percentage of traders that had attained secondary education. Ownership of storage facilities ranked highest (73%) in Nairobi and lowest (8%) in Mombasa. Busia had 33% of traders owning storage facilities. The low figure reported in Mombasa could be attributed to quick sales of fresh tubers that did not require storage facilities. Out of the number of cassava traders interviewed, only 25% in Mombasa were selling other agricultural products. In Nairobi, all traders interviewed were selling other agricultural products besides cassava while in Busia, 78% were dealing with other agricultural products. Other agricultural products sold in Mombasa included other root crops (33%), while in Nairobi and Busia cereals were dominant at 87% and 85% respectively. 90 80

Male

% respondents

70

Female

60 50 40 30 20 10 0 Mombasa

Nairobi

Busia

Region Figure 5. Gender of cassava traders in Mombasa, Nairobi and Busia.


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BUSINESS ACTIVITIES Figure 6 shows the overall trend in the trade of cassava and cassava-based products in the three study regions. Sale of cassava and cassava-based products in Mombasa, Busia and Nairobi dates as early as 1956, 1962 and 1987 respectively. In Mombasa, cassava crisps and fried fresh cassava constituted 8% and fresh roots 92% of cassava and cassava products sold. In Nairobi, boiled cassava constituted 6%, cassava flour 25%: dried chips 69% of cassava and cassava products being traded in. In Busia cassava flour constituted 33% and dried chips (for milling) 67% of the cassava processed products sold. In Mombasa, the minimum storage period for cassava and cassava-based products was one day with a maximum of four days. This was attributed to the fact that they sold fresh tuberous roots only. Though cassava was stored for a maximum 4 days, 75% of the traders experienced storage losses. In Nairobi the cassava products could be stored for up to 90 days because they were processed as dried cassava chips for milling. Although cassava was stored for a longer duration in Nairobi, storage losses were experienced by only 25% of the traders. In Busia, cassava-based products could be stored for up to 12 days but storage losses were reported by 25% of traders. Losses in storage were attributed mainly due to storage pests like rats and weevils and rotting.

40

Number of traders

30

20

10

0

2006

2005

2004

2003

2002

2001

2000

1998

1997

1992

1990

1989

1988

1987

1984

1980

1957

1956

Year when cassava business started

Figure 6. Overall trend in cassava and cassava-based products in Busia, Nairobi and Mombasa for a period of 50 years.



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On treatment of cassava and cassava-based products during storage, none of the traders was applying any treatment in all the study regions. The reasons given for not applying any treatment to cassava and cassava-based products differed with region. In Mombasa, 75% of the respondents reported that the cassava sells quickly because of a ready market and hence does not need treatment while in storage. Similarly in Nairobi 50% of the respondents reported that cassava was sold quickly, while 29% of respondents reported that cassava products were not affected by pests. In Busia 75% of the respondents reported that cassava sold quickly due to a ready market while 13% reported that pests did not attack stored cassava products.

DEMAND CHARACTERISTICS Demand characteristics for the sampled cassava and cassava-based products traders are shown in Table 4. The major customers of cassava and cassava-based products in Mombasa were final consumers (67%), retailers (25%) and processors (8%). In Nairobi 72% of customers were final consumers, 6% wholesalers, 12% retailers and 10 percent processors. In addition, the processors in Nairobi were mainly millers specializing in composite flour. In Busia 82% of customers were final consumers, 5% wholesalers, 5% retailers and 8% processors. Both males and females constituted 67% and 62% of main customers in Mombasa and Nairobi respectively. In Busia the major customers were females (56%). In the three study regions, main customers of cassava and cassava-based products were aged between 20 and 50 years. In Mombasa, the average price of a fresh root was 13 shillings during scarcity and 8 shillings during abundance. In Nairobi, the average price of a 2 kg tin (gorogoro) was 69 shillings during scarcity and 55 shillings during abundance. In Busia, the average price of a 2 kg tin was 35 shillings during scarcity and 31 shillings during abundance. In Mombasa, an average of 5 roots was sold during both scarcity and abundance period. In Nairobi, an average of 7 tins was sold during scarcity and 6 tins during abundance. In Busia, an average of 32 tins was sold during scarcity and 21 tins during abundance. The low volume of sales in Mombasa and Busia during abundance is attributed to the fact that most farmers have harvested enough cassava for their household use during this period. In Nairobi, the low volume of sales during the same period is attributed to the high volumes of cassava being brought to Nairobi from western Kenya.

SUPPLY CHARACTERISTICS OF CASSAVA TRADERS Supply characteristics for the cassava traders sampled are shown in Figure 5. In Mombasa 67% of the principal suppliers of cassava and cassava-based products were both male and female. In Nairobi 53% of cassava and cassava-based products suppliers were women. In Busia 63% of cassava suppliers were both men and women. In Mombasa and Nairobi, 85% and 94% respectively, of principal suppliers were between 20 and 50 years old while in Busia, 100% of suppliers were in that age class. In Mombasa 67% of supplies came from Kilifi and 33% from Kongowea market. In Nairobi, 81% of


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supplies came from Gikomba market, 13% from Kibera and 6% from Wakulima market. In Busia, 89% of supplies came from Busia market and 11% from Uganda. The supply prices of cassava and cassava-based products varied across the three study regions with Busia recording the lowest fluctuation throughout the year. In Mombasa, the average price for fresh roots per 90 kg was 900 shillings during scarcity and 400 shillings during abundance. In Nairobi, the average price of dried cassava chips was 43 shillings for a 2 kg tin (gorogoro) during scarcity and 31 shillings during abundance. In Busia the average price of dried cassava chips was 22 shillings for a 2 kg tin during scarcity and 19 shillings during abundance. Supply constraints were reported by 58% of respondents in Mombasa, 25% in Nairobi and 56% in western. The main supply constraints reported at the coast were lack of cassava during scarcity (43%), transport (29%), competition (14%) and lack of credit (14%). In Nairobi, the main supply constraints were competition from other related products like maize (50%) and lack of cassava during scarcity. In Busia, most important constraints recorded were transport (40%), lack of sorghum and finger millet for blending cassava (20%), lack of cassava during scarcity (20%) and unfavourable weather which makes the cassava chips not to dry well (20%). Table 4. Characteristics of cassava and cassava-based products customers

Characteristic

Coast

Major customers Final consumers Wholesalers Retailers Processors Gender of main customer Male Female Both Age class of main customers 20-50 years >50 years All ages Customers’ desirable attributes Sweet taste White colour Ease of milling

Region Nairobi Western Percent respondents

67 0 25 8

72 6 12 10

82 5 5 8

8 25 67

13 25 62

0 56 44

83 0 17

88 6 6

100 0 0

75 25 0

0 50 50

56 44 0

13 8 5 5

69 55 7 6

Mean Selling price during scarcity Selling price during abundance Daily quantity sold during scarcity Daily quantity sold during abundance


35 31 32 21


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Table 5. Characteristics of cassava and cassava-based products suppliers

Characteristic

Coast

Gender of principal supplier Male Female Both Age class principal supplier 20-50 years >50 years All ages Experience any supply constraints Yes No Most important constraints Competition Lack of cassava during scarcity Lack of credit Transport Bad weather Lack of sorghum/millet

Region Nairobi Western Percent respondents

25 8 67

14 53 33

0 38 62

85 0 15

94 6 0

100 0 0

58 42

25 75

56 44

14 43 14 29 0 0

50 50 0 0 0 0

0 20 0 40 20 20

900 400

43 31

Mean Buying price during scarcity Buying price during abundance

22 19

CONCLUSION In Mombasa, cassava and cassava-based products were sold at the main market (Kongowea). In Nairobi, cassava and cassava-based products were sold in local markets (Gikomba and Kibera) and hotels. In Busia, cassava and cassava-based products were sold at the main and secondary markets. In Mombasa and Nairobi, cassava traders are mainly wholesalers, wholesalers/retailers and retailers while in Busia they were both wholesalers and retailers. In Mombasa, the majority of those marketing cassava and cassava-based products were males while in Nairobi and Busia the business was dominated by females. In Mombasa and Busia, the cassava business was dominated by the native people, while in Nairobi the business was dominated by migrants. The main cassava products sold in Mombasa were crisps and fried chips and fresh tuberous roots while in Nairobi the main products were boiled cassava, flour and dry chips. In Busia cassava flour and dried chips (for milling) were the main products. In Mombasa the major customers of cassava and cassava-based products were final consumers, retailers and processors while in Nairobi major customers were final consumers, wholesalers, retailers and millers. In Busia customers were final consumers, wholesalers, retailers and processors. In


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Mombasa the principal suppliers of cassava and cassava-based products were both male and female. In Nairobi the principal suppliers were women. In Busia principal cassava suppliers were both men and women. The main supply constraints reported at the coast were lack of cassava during scarcity, transport, competition and lack of credit. In Nairobi, the main supply constraints were competition from other related products like maize and lack of cassava during scarcity. In Busia, most important constraints recorded were transport, lack of sorghum and finger millet for blending cassava, lack of cassava during scarcity and unfavourable weather which makes the cassava chips not to dry well.

REFERENCES FAO, (1990): Roots, Tubers, Plantains and Bananas in human nutrition. FAO, Rome, Italy. Goering, T.J. 1979. Tropical root crops and rural development. World Bank Staff working Paper No. 324. Washington, D.C., World Bank. Githunguri, C. M. 1995: Cassava food processing and utilization in Kenya. In: Cassava food processing. T. A. Egbe, A. Brauman, D. Griffon and S. Treche (Eds.) CTA, ORSTOM, pp119-132. Githunguri, C. M., I. J. Ekanayake, J. A. Chweya, A. G. O. Dixon and J. Imungi. (1998): The effect of different agro-ecological zones on the cyanogenic potential of six selected cassava clones. Post-harvest technology and commodity marketing, .IITA, 71-76pp. Githunguri, C.M., E. G. Karuri, J. M. Kinama, O. S. Omolo, J. N. Mburu, P. W. Ngunjiri, S. M. Ragwa, S. K. Kimani and D. M. Mkabili. (2006a) Sustainable Productivity of the Cassava Value Chain: An Emphasis on Challenges and Opportunities in Processing and Marketing Cassava in Kenya and Beyond. A project proposal present to the Kenya Agricultural Productivity Project (KAPP) Competitive Agricultural Research Grant Fund, Research Call Ref No.KAPP05/PRC- CLFFPS –03. KAPP Secretariat 106p. Githunguri, C.M., Karuri, E.G., Kinama, J.M., Omolo, O.S., Mburu, J.N., Ngunjiri, P.W., Ragwa, S.M. and Mkabili, D.M. (2006b): Sustainable Productivity of the Cassava Value Chain: An Emphasis on Challenges and Opportunities in Processing and Marketing Cassava in Kenya and Beyond. Githunguri, C. M., S.M. Ragwa and J. Abok. (2008a). Proceedings of the Cassava Value Chain Project Collaborators and Stakeholders’ in Kenya Inception Workshops. 2008 KARI Katumani Research Centre, Cassava Value Chain Project. 123pp. Githunguri, C.M., Kinama, J.M., Karuri, E.G., Gatheru M. and Ragwa, S.M. (2008b). Situational Analysis of Cassava Production, Processing and Marketing in Kenya. KARI Katumani Research Centre. Pp 51. Githunguri C. M, S. M Ragwa and S. Yatta. 2009a. Culinary Perceptions of Cassava-Based Products by Hoteliers’ Based in Kibwezi in Semi-Arid Eastern Kenya. In: C.M. Githunguri, Kizito Kwena, Erick Mungube and Mwangi Gatheru (eds). KARI Katumani Research Centre annual report 2008. Pp. 113. Githunguri C. M., S. M Ragwa and S. Yatta. 2009b. Popularization of Eight Cassava-Based Products and Recipes among Hoteliers and Consumers in Kibwezi in Semi-Arid Eastern



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Kenya. In: C.M. Githunguri, Kizito Kwena, Erick Mungube and Mwangi Gatheru (eds). KARI Katumani Research Centre annual report 2008. Pp. 113. GoK. 2010. Agricultural Sector Development Strategy (ASDS, 2010 - 2020). Pp. 101. Greene, W. H. (2000). Econometric Analysis. Upper Saddle River, New Jersey, Prentice-Hall, Inc. International Fertilizer Development Center (IFDC). (2012). Cassava+ Opportunities for Africa’s Smallholder Cassava Farmers. Cassava Project Report. IFDC Kenya, Duduville. Pp 6. Kadere, T.T. 2002. Marketing opportunities and quality requirements for cassava starch in Kenya. In Proceedings of regional Workshop on improving the cassava sub-sector, held in Nairobi, Kenya, April 2002, 8-18, pp. 81 – 86. KARI. 1995: Cassava Research Priorities at the Kenya Agricultural Research Institute, Cassava Priority Setting Working Group. Makokha, J. and Tunje, T.K. 2000: Study of Traditional Utilization and Processing of Cassava and Cassava Products in Kenya, First interim technical and financial report, JKUAT/EARRNET. Mbwika, J.M 2002. Cassava sub-sector analysis in the Eastern and Central African region. In Proceedings of regional Workshop on improving the cassava sub-sector, held in Nairobi, Kenya, April 2002, 8-18, pp. 8-18. Ministry of Agriculture. (2011): National Cassava Development Strategy 2012-2016. Ministry of Agriculture, 70pp. Ministry of Agriculture. (2009): Ministry of Agriculture Strategic Plan 2008 – 2012. Ministry of Agriculture. (1999): Provincial Annual Reports. Nweke, F. I., D. S. C. Spencer and J. K. Lynam. 2002. Cassava transformation. International Institute of Tropical Agriculture. 273p. Scott, G. J. (1995). Methods for Evaluating the Market Potential of Processed Products. Prices, Products, and People: Analyzing Agricultural Markets in Developing Countries. G. J. Scott. London, Lynne Rienner Publishers, Inc. Wambugu, S. M. and Mungai, J. N. 2000: The potential of cassava as an industrial/commercial crop for improved food security, employment generation and poverty reduction in Kenya, KIRDI.





Chapter 19

WILD RELATIVES OF CASSAVA: CONSERVATION AND USE Márcio Lacerda Lopes Martins1,*, PhD Carlos Alberto da Silva Ledo2, PhD Paulo Cezar Lemos de Carvalho1, PhD André Márcio Amorim3,4, PhD and Dreid Cerqueira Silveira da Silva1, PhD 1

Federal University of Recôncavo of Bahia, Center of Agronomical, Environmental and Biological Science, Bahia, Brazil 2 Embrapa Cassava and Fruit, Bahia, Brazil 3 State University of Santa Cruz, Department of Biological Science, Ilhéus, Bahia, Brazil 4 Herbarium of Center of Research of Cocoa, CEPEC, Ilhéus, Bahia, Brazil

ABSTRACT The genetic improvement of cassava is directly related to the increase of productivity of culture, this has an important role in feeding in developing countries. Therefore, knowledge about the biology, distribution and conservation status of their wild relatives is essential, because it allows the harvest and conservation efforts to be directed to those unfamiliar species of which there are more severe threats. These data become even more relevant since some of their wild relatives are resistant to common diseases, such as whitefly. This chapter discusses the closest conservation of the wild relatives of cassava from the evaluation of biological collection, as well as recent collections by authors in Brazil and their cultivation in Germplasm banks. This work is part of a program of study of wild species of Manihot developed in partnership with the Federal University of Bahia Recôncavo (UFRB) and Cassava and Fruits National Research Center (CNPMF) of the Brazilian Agricultural Research Corporation (EMBRAPA) both located in Cruz das Almas, Bahia, Brazil. The program, started in 2010 aims to harvest and cultivate wild * Author for correspondence ([email protected], 55 75–3621-3176; 55 75–98127-1987).


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M. Lacerda Lopes Martins, C. A. da Silva Ledo, P. C. Lemos de Carvalho et al. species of the genus with taxonomic, conservation and agronomic purposes, especially with regard to improving the cassava (M. esculenta Crantz). Harvests were made during the first six years of the project in four Brazilian regions encompassing 14 states and over 150 municipalities mainly from the central and eastern South America region. About 60 of the 80 south American species of Manihot in various environments were seen and harvested. Thirteen species phylogenetically close to cassava were selected to discuss their conservation status based on their occupation Area (AOO), Occurrence Extension (EOO), and potential use for the improvement of this culture. According to the International Union for Conservation of Nature (IUCN) criteria, all species showed some degree of threat, two considered Critically Endangered and the other Endangered according to AOO. The EOO analysis showed different results with only three endangered species, which can indicate subsampling of natural populations of these species. In preliminary studies among the analyzed species only three presented suggest valuable features to cassava improvement as resistance to pests and diseases, such as African cassava mosaic virus, bacterial blight, anthracnose, green mite and caterpillar ‘mandarová,’ or high dry matter content and protein in roots. However, the fact that some species were not included in the analysis, because they do not appear in the same M. esculenta clade, which also presents important features for improvement, suggests that they may also be the subject of breeding programs due to the ease of hybridization verified gender. Regular expeditions of harvest of wild species of Manihot, that were conducted since 2010 have helped to increase the distribution of data and also to broaden the panorama of each species ‘in loco,’ allowing the verification of their habitat conservation status, the number of individuals of each population, etc. However, expeditions have not been made yet specifically aimed at the closest relatives of cassava, covered in this study. It is emphasized that maintaining wild relatives of cassava germplasm bank is a practice of fundamental importance for the improvement of this culture, because the programs rely on the introduction of alleles with valuable agronomic traits contained in these species to minimize the limitations found in culture as pests and diseases.

INTRODUCTION The species of Manihot Mill. are exclusively Neotropical with majority distribution in South America, but with an important diversity center in Mexico (Nassar 1978a, Rogers & Appan 1973). The wide range of variables characters within the same species hinders the precise delimitation of various taxa and the number of accepted species is variable. Taking the example of Brazil, Rogers & Appan (1973) report 80 species, Allem (2002) estimates that the number of species varies between 47 and 50, while, Cordeiro et al. (2015) reports 76. The wild species of the genus for the improvement of cassava (Manihot esculenta Crantz) is important as it is considered the 4th main source of starch in the world which makes the definition of species of Manihot a relevant issue. At the same time the natural populations of these species are under constant threat due to the expansion of the agricultural frontiers and cattle raising, and are usually eliminated from rural areas due to the presence of hydrocyanic acid (HCN) (Allem 1999, Nassar 1978b). These actions accelerate the necessity to update the knowledge of the group with regard to the identity of their species, especially in relation to their conservation.


Wild Relatives of Cassava

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CLASSIFICATION HISTORY Originally described by Bauhin (1651), from cultivated samples in Brazil, Manihot has only been validated by Miller (1754) in the Gardener’s Dictionary. Crantz (1766) presented the first valid epithet for the genus (M. esculenta) from cultivated cassava specimens. From there several names have been published for this species (e.g., M. aipi Pohl, M. dulcis (J. F. Gmel) Pax, M. utilissima Pohl) (Rogers & Appan 1973). Pohl (1827), in Plantarum Brasiliae Icones et Descriptions, provided the first monograph about Manihot. In this work 48 species were presented, almost all accompanied by descriptions and boards. The author has been in Brazil and observed the material in the field, which made his descriptions and robust circumscriptions, with many species accepted today. Throughout the nineteenth century, Steudel (1840-41) combined various species originally described in Jatropha in Manihot, expanding and redefining the genus division. The second and third monographs of Manihot were published by Müller (1866, 1874). In his first work the author has listed 43 species, further divided into eight groups, in addition he presented the first identification key for species. Some species have expanded their area in relation to Pohl’s work (1827) (e.g., M. gracilis Pohl; M. palmata Pohl; M. tripartita (Spreng) Müll. Arg.). This paper presents descriptions that include characters related to flowers and inflorescences but lacks illustrations for species recognition. In Flora Brasiliensis (Müller 1874) 71 species were included which were divided into 10 groups, with few illustrations. In all Müller (1866, 1874) described 64 taxa between species and subspecies and added important distribution records, despite this he has not done any work in the field. Pax (1910) recognized 128 species in 11 sections. The author made a comprehensive review of the bibliography of existing collections and produced the first section in Manihot and the first hypothesis about the possible phenetics relations within the group. Ule (1907, 1914) described 13 species found in Bahia, with an emphasis on producing latex for rubber manufacturing, and discussed their relationship with other species of Manihot. Croizat (1943) assembled 17 species in South America and commented on the importance of establishing criteria to consider morphological diversity displayed by most species and their geographical distribution for the elaboration of a more consistent rating for the genus. Finally, Rogers & Appan (1973) presented in Flora Neotropica the latest monographic study of the genus. Many advances to the group’s taxonomy have been proposed by the authors who provided an important compilation of knowledge about Manihot, describing 13 taxa and synonymizing others to widely verify species morphologically (e.g., M. caerulescens Pohl; M. tripartita), which reduced the number of species to 98. The authors acknowledged 19 sections based on morphological phenetics analysis, some with a single species, (e.g., Sect. Grandibracteatae Pax emend D. J. Rogers & Appan, Tripartitae D. J. Rogers & Appan) and M. pauciflora (T. S. Brandegee) D. J. Rogers & Appan was recombined in genus Manihotoides D. J. Rogers & Appan, which is probably extinct in the wild (Nassar 2002). Unlike some of his predecessors, Allem (1977, 1978, 1979abc, 1980) discussed various aspects related to division of Brazilian species (e.g., M. anomala Pohl, M. caerulescens Pohl, M. carthagenensis Müll. Arg. and M. hilariana Baill.) based on his extensive field experience. In the late 1980s, this author published four new species (Allem 1989a) and the


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M. Lacerda Lopes Martins, C. A. da Silva Ledo, P. C. Lemos de Carvalho et al.

revision of Section Quinquelobae Pax emend Rogers & Appan, based on morphological, palynological and cytogenetic (Allem 1989b). The author has also published new taxa and provided contributions to Glazioviannae Pax emend Rogers & Appan section (Allem 1999, 2001), and finally proposed a phenetic classification model, which includes about 50 species occurring in Brazil in 16 groups, and suggested probable phylogenetic relations among themselves (Allem 2002). Currently, some researchers have been devoted to genus study in South America, which has generated regional flora (Rodrigues 2007, Sátiro & Roque 2008, Mendoza 2010, CarmoJr et al. 2013) and several species have been described (Martins et al. 2011, 2014, Mendoza et al. 2013, Silva et al. 2013, Martins & Ledo 2015, Silva 2016).

MORPHOLOGICAL CHARACTERS The Manihot genus can usually be recognized by lobed leaves with purplish hues and inflorescences racemose or paniculate with two basal pistillate flowers, accompanied by bracts and bracteoles usually evident (Rogers & Appan 1973). Furthermore, the formation of hydrocyanic acid (HCN) is common when the tissues suffer some injury (Dunstan et al. 1906). These characters, however, should be viewed with caution for the distinction of its kind (Allem 1977). For Léotard et al. (2009) Differentiation of the Manihot species based solely on morphological characters may lead to errors since some characteristics are highly variable due to environmental plasticity or developmental. Habit variation is observed for most species and seems to be directly related to the environment they occupy (Duputié et al. 2011). In general, the cerrado species have become shrubby or subshrubs, while species of the semiarid region tend to be woody and forest vinelike (Allem 1999; Nassar et al. 2008). The habit change according to the environment occurs with some species and can generate taxonomic doubts if the analysis is restricted to the herbarium materials with inaccurate notes (Allem 1999). According to Allem (1979b) the external morphology of the vegetative organs, especially leaves, is presented as a consistent characteristic for differentiation of the species closely related to Manihot, however, this proves to be fragile in related species. The author’s view, where the species have an extensive list of character states for certain structures (leaves, habit, pubescence, etc.) is supported in results found by Duputié et al. (2011). For these authors, the recent genus origin makes it difficult the species lines which are definitely isolated, so the delimitation of species and publication of new taxa should be surrounded by caution (Duputié pers. comm.). Pohl (1827) uses reproductive organs features to define the characters “essential” and “natural” within Manihot, however, in their diagnoses refers only to vegetative characters. In Manihot, the variation of the shape of the leaves is common, and one species may provide leaves 3, 4, 5, 6, 7, and 9-lobed, in addition several species are associated with whole leaves inflorescences (Allem 1979bc). This variation cannot generally be observed in herbarium materials and exclusive analysis of these materials may have contributed to the increase in the number of species of the genus recorded in Pax (1910). Some strains, such as M. caerulescens, M. pentaphylla Pohl and M. tripartita, are full of synonyms because of naming to the various forms that have their leaves (Rogers & Appan 1973). Another feature that



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should be noted is the nature of the leaves. Allem (1999) reports four species with leaves composed for Manihot, among them three from the Amazon. For Rogers & Appan (1973), these species have a strong constriction between leaf lobes of some species of the genus that resembles the leaflets, but its leaves are simple. The morphology of the stipules is important for the diagnosis of some taxa in Manihot (e.g., M. pusilla Pohl and M. stipularis Pax; Pax 1910), but they are usually caducous, and are used little in the delimitation of species of the genus (Rogers & Appan 1973). The inclusion of traits related to reproductive organs in the delimitation of Manihot species, as a kind of inflorescence size and margins of floral bracts and the coating of the fruits were introduced by Müller (1866, 1874). The shape of the bracts and bracteoles and inflorescence pattern are presented differentially which is useful in species distinction (Allem 1984). Some typically have bracts foliaceous (e.g., M. caerulescens, M. jacobinensis Müll. Arg. and M. tripartita), other setaceous (e.g., M. carthagenensis), while a few have variation in its form (e.g., M. anomala, Allem 1979b). The format of the bracts tends to remain stable in the same individual and the same population. The opposite is verified for the type of inflorescence (Allem 1977). Racemose inflorescences may occur solitary or in groups and some species may have panicles and racemes in the same individual (e.g., M. carthagenensis) (Allem 1979c). Nevertheless, these characteristics were used for the distinction of species of various sections which contributed to the inconsistency of the current rating. Rogers & Appan (1973) considered the shape of the flower bud staminate as a key character for the distinction of Manihot species, leaving aspects of fruit morphology in a lower plane. Flower buds, bi-fusiform, oval and orbicularis are diagnostic for species and may have subtle variations between pistillate and staminate flowers (Rogers & Appan 1973, Allem 1989a, 2001). Croizat (1943) highlights the importance of fruits for the genus. The fruits of Manihot are commonly found as capsules, but bacaceous fruit can be found in a small number of some related species (Allem 1999, Duputié et al. 2011). Barroso et al. (1999) includes the fruits bacaceous and drupe between the fruits of Euphorbiaceae, although some authors prefer to use the term indehiscent capsule (e.g., Oliveira & Oliveira 2009). Webster (1958) relates the kind of fruit to the size of the Phyllantaceae species. The same has not been tested in Euphorbiaceae but there is evidence that this relation does not exist in this group (Allem 1999). The indehiscence fruit in Manihot species apparently is related to the type of environment that they occupy which is directly linked to the type of dispersion presented by some species. The morphological diversity of Manihot fruit involves differences in their overall shape, size, and shape in the apex of the presence or absence of ribs on the septum. This last character has to be variable in certain species, in which the fruits can be smooth or ribbed, through several intermediate stages (e.g., M. caerulescens) (Allem 2001). Morphological variation in leaves, bracts, staminate buds, and fruits is shown in Figure 1. Unlike fruit, little taxonomic importance is given to the morphology of the seeds in Manihot. The species of the genus usually have oval seeds, ash brown, with dark spots, on the forehead, as well as usually have well-developed caruncles. Within Euphorbioideae, the morphology of the seed, especially the thickening of the integument and the presence of aryl, proved widely diverse (Tokuoka & Tobe 2002). Webster (1994) points out that caruncles presents considerable taxonomic and evolutionary interest within the Euphorbiaceae.


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Figure 1. Morphologic diversity in Manihot species. (a)Leaves and stipules (note: entire and lobed leaves, peltate or not, setaceous and foliaceus stipules); (b)Staminate buds and bracts (note: bifusiform and ovoid buds, semifoliaceus and foliaceus bracts). (c)Fruits (note: the variation in the shape, colour and the presence of ribs) (Photo by authors).

The morphology of the pollen-grains presents homogenous Manihot (Allem 1993), though useful in differentiating some species of genera of Euphorbiaceae (Cruz-Barros et al. 2006, Cooke et al. 2010), within the subfamily Crotonoideae the-pollen-grains are typically inaperturates with exine formed by triangular elements connected to a network ‘muri’ with short columellae (Nowicke 1994), and those having exine periporate are considered “standard Manihot” (Punt 1962). Unlike macroscopic characters, the use of anatomical characters for Manihot species distinction is restricted, and most of the work has focused on cultivated species (GracianoRibeiro et al. 2008, 2009, Bomfim et al. 2011.). Hybrids tetraploid M. esculenta with M. oligantha Pax & K. Hoffm. showed a higher number of vessel elements and absence of growth rings in comparison with diploid hybrid, indicating a greater adaptation to xeric environments (Graciano-Ribeiro et al. 2008). The adaptation to this type of environment is one of the main characteristics of the species Manihot and, accordingly, the allotetraploid origin of the group may have been presented as of great adaptive value (Nassar 2000a). White latex and laticifers are commonly articulated in Manihot and Hevea Aubl., unlike the rest of Crotonoideae subfamily in which latex of different colors and unarticulated laticifers are more common (Rudall 1994). Few species of Manihot, however, have cream or yellow latex (Allem 1979b). Differences in the organization of tissues in the pericarp of fruits of M. caerulescens and M. tripartita are evidence of the importance of the morphology of fruits for their systematic, and that the use of these characters can prove useful (Oliveira & Oliveira 2009).



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Figure 2. Cross section of the mesophyll of the Manihot species of Chapada Diamantina, Bahia, Brasil, (Note: Epidermis variably papilose. (LP) – lacunose parenchyma, (PP) – palisade parenchyma, (st) – stomata. Scale bars: a, c, f = 60 μm; b, d, e, g = 30 μm)(Photo by I. Cunha-Neto and F. Martins, in Cunha-Neto et al. 2016, subm.).

The most comprehensive studies on the anatomy of wild species of the genus were developed by Allem (1984) evaluating the anatomy of the petiole, the type of venation, the ornamentation of the cuticle and the morphology of the epidermal cells. Epidermal waxes presented various forms, some even have been used to support the description of new species (e.g., M. xavantinensis D. J. Rogers & Appan) but have not enough stability for use with taxonomic purposes (Allem 1989b). The morphology of the leaf epidermal cells, however, proved to be an important character to be considered, especially in their abaxial surface (Allem 1984). Four groups were differentiated in the Quinquelobae section based on the absence of ornamentation on the leaf surface, or the presence thereof in the form of ridges, papillae or reticulated (Allem 1989b). Cunha-Neto et al. (2014) discuss the use of leaf anatomy in the differentiation of species of M. violacea Pohl complex group showing important characters as the cross section of the petiole, the shape of vascular bundles and the presence of epidermal papillae (Figure 2).

GENETIC AND MOLECULAR CHARACTERS Some Euphorbiaceae groups have great stability in the number and morphology of chromosomes, while others show significant variation and may contribute to their taxonomy (Hassall 1976). Only the genus Euphorbia a diploid nucleus may have between 12 (Euphorbia


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retusa Forssk) and 200 chromosomes (E. ferox Marloth) (Hans 1973; Hayirlioglu-Ayaz et al. 2002). The base chromosome number within the family is variable with the main values x = 7 and x = 13 and generally trend to reduce the size of the chromosomes as their number increases (Hans 1973). Among the genus near Manihot, several species of Cnidoscolus Pohl and Hevea have 2n = 36 which suggests that genus are cytologically uniform (Majumder 1964, Miller & Webster 1966, Leicth et al. 1998). A different situation was recorded for Jatropha L. presenting 2n = 20 or 22 (Hans 1973, Sasikala & Paramathma 2010). Jennings (1963) suggests that Manihot is an allotetraploid derivative of the basic number x = 9. The chromosome number found in the group is invariably 2n = 36, and their chromosomes are small, metacentric or submetacentric (Carvalho & Guerra 2002). The high frequency of regular meiotic pairing and large pollen viability observed in interspecific hybrids (Nassar & Freitas 1997) may be a result of this karyotype similarity, both in number and in size and shape (Carvalho & Guerra 2002). However, there are records of low pollen viability and deficiencies in the pairing of chromosomes (Nassar 2000a) as well as structural differences in the chromosomes and variable pollen viability in F1 generations originated from interspecific hybrids of Manihot (Bai et al. 1993). Nassar (2000b) believes that allopolyploidization is directly related to the rapid appearance of species lineages of Manihot, which led to weak reproductive barriers. Various reports of hybrids produced between each other wild species and the cultivated species confirm the absence of effective reproductive barriers for some groups (Nassar 1985, 2003, 2006, Nassar et al. 2008). In relation to the molecular data, regions that provide good results for the phylogeny of other groups, such as the spacer trnL-F useful in phylogenetic analyzes of Croton L., Macaranga Thouars and Mallotus Lour. (Berry et al. 2005, Kulju et al. 2007) does not exhibit phylogenetic signals that allow the distinction of most Manihot species (Chacon et al. 2008). This apparently is due to the fact that the DNA sequences being very well preserved in the Manihot species, thanks to its recent origin, and therefore uninformative (Leotard et al. 2009, 2011 Duputié et al.). Nevertheless, the results of these studies support the monophyly of the genus, which can be divided into the Central American and South American lineage, and the close relationship between biogeographic and the main lineages, and the need of infrageneric group taxonomic review. The definition of informative regions will allow them to be used as markers for introgression and classification of germplasm banks (Roa et al. 1997). Regions G3pdh nuclear gene has shown to be useful in phylogenetic and taxonomic analyzes involving the Amazon species M. esculenta subsp. flabellifolia (Pohl) Ciferi x M. surinamensis D. J. Rogers & Appan, and M. aff. quinquepartita Huber ex D. J. Rogers & Appan x M. brachyloba Müll. Arg. (Leotard et al. 2009), as well as most of the wild species of the genus (Chacon et al. 2008, Duputié et al. 2011). The relation between M. esculenta and their wild relatives, as well as the definition of its center of origin constitute the most common approaches inferred using molecular markers (Olsen & Schaal 1999, Allem 2002, Olsen 2002, Leotard et al. 2009). This species have been over investigated from the point of view of the genome which is actually a ‘flagship species’ in many evolutionary studies on larger scales (Daniell et al. 2008). And RAPD markers and AFLP have been effective in this matter, particularly in defining the positioning M. flabellifolia Pohl and M. peruviana Müll. Arg. (Roa et al. 1997, Colombo et al. 2000). These species were distinct and belonging to different sections by Rogers & Appan (1973), they had



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their situation redefined as subspecies of M. esculenta (Allem 2002), but apparently are synonymous (Colombo et al. 2000). The genetic affinity between these wild species and M. esculenta was used for determination of gene pools within Manihot. Allem et al. (2001) consider as the primary gene pool subspecies of M. esculenta (M. esculenta subsp. esculenta, M. esculenta subsp. flabelifolia, M. esculenta subsp. peruviana) and M. pruinosa Pohl, and as pool other secondary gene 13 species from morphological evidence and reproduction tests. Other studies based on seed proteins proved useful for the evaluation of the similarity of 19 species of the genus, and showed the greatest similarity between geographically related species (Grattapaglia et al. 1987).

REPRODUCTIVE BIOLOGY Manihot species are characterized by monoecious with pistillate and staminate flowers on the same inflorescence, except for some dioecious species of Stipularis Pax emend D. J. Rogers & Appan section (Rogers & Appan 1973). Its inflorescences are protogynous, so that the staminate flowers located at the top of inflorescence do not become anthesis when the pistillate have been fertilized or aborted in a range of approximately 20 days (Halsey et al. 2008). The selfing may occur as pistillate and staminate flowers of different branches can open simultaneously (Jennings & Iglesias 2002). Reproductive barriers are weak among the species of the genus (Jennings 1963). Cruz (1968) highlights that the Manihot species can interbreed causing natural hybrids as evidence in the cytogenetic group. Several interspecific hybrids between wild species and accessions of cultivated species were obtained, especially when the latter acts as a recipient of pollen grains (Nassar 1980) and even among wild species the process of hybridization seems to find great obstacles (Bolhuis 1953, Jennings 1959, Magoon et al. 1970, Nassar 1980). There are reports of natural hybrids between M. alutacea D. J. Rogers & Appan and M. reptans Pax, and between M. caerulescens and M. tripartita favored by low barriers and overlapping habitats (Nassar 1984, Nassar et al. 2008). Olsen & Schaal (2001) suggest the occurrence of inbreeding in natural populations of Manihot evidenced particularly by the low heterozygous rate, which may be due to the lack of genetic self-incompatibility systems within the genus and the seed dispersal mechanism (dehiscence explosive) that as a rule, does not reach great distances. Moreover, apomixis can influence this process. Nassar et al. (2008) showed that the polyploidy can offer the heterozygosity necessary for initiating the process of speciation, and apomixes could allow hybrid showing reproductive disorders which prevent and maintained seed source for fertilization. The apomixis rates in Manihot are variable and are related to the occurrence of apospory (development of embryo sacks for ovule cell mitosis), the main source apomixes mechanism in angiosperm (Nassar 2000b). Allem et al. (2001) evaluating M. dichotoma Ule and M. glaziovii Müll. Arg. concluded that the crossing is possible but gene transfer is difficult with the F1 tendency to be sterile, as well as chromosomes presenting weak pairing or being univalent. This scenario is shown different from that in Jatropha L. were the species presents variably isolated with different floral arrangements and phylogenetic relationships which may


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inferred with from the reproductive success rates (Dehgann 1984). Some species of this genus occurring in the bush, however, have overlap in flowering period and aggregate distribution with predominantly autochoric dispersion, factors that favor the formation of natural hybrid (Neves et al. 2010). Phenological studies in Manihot are scarce. Data are directed generally to the study of M. esculenta (Reich et al. 2004, Rós et al. 2011) or, as in wild species, vegetative characters such as loss of leaves in caatinga environments with few data on the formation of flowers and fruits (Machado et al. 1997, Tannus et al. 2006).

BIOGEOGRAPHY The distribution of Manihot is restricted to the Neotropics. Its species form two groups geographically isolated in Central America and South America, with only M. brachyloba and M. carthagenensis occurring in both regions (Rogers & Appan 1973, Allem 1979c). The monophyly of these two groups has been supported on molecular studies and apparently the disjunct distribution of these species was the result of human introduction (Rogers & Appan 1973, Chacon et al. 2008, Duputié et al. 2011). Croizat (1943) highlighted the important role of geographical isolation in the divergence of characters between populations of Manihot, this is essential in the process of speciation. This work may have influenced the review of Rogers & Appan (1973), which unlike their predecessors began their work based on geography, gender separating the groups of North/Central America and South America. Currently there are four recognized centers of diversity for the genus, distributed in descending order of number of species in central Brazil, Mexico, northeast Brazil and southern Mato Grosso do Sul and Bolivia (Nassar 1978a, 2000bc). Several microcenters of diversity can be recognized and its origin is probably related to frequent hybridization and the rugged topography of the environments where these species occur, which contributes to the isolation of small gene pools and consequent speciation (Nassar 1978ac, 1979ab, 1982). The cerrado is the richest ecosystem in the Manihot species and its origin seems to be corresponding with the largest group of diversification period (Duputié et al. 2011). Other environments such as caatinga, rain forest and dunes are less representative in number of species, but new records have been made (Allem 1989b, Martins et al. 2011). The Manihot species tend to be restricted or endemic to small areas (Rogers & Appan 1973). This pattern is observed for several species of central Bahia, in Chapada Diamantina and Chapada dos Veadeiros, that harbor together over three dozen species, some of which are recently described (Rogers & Appan 1973, Martins et al. 2014, Mendoza et al. 2015, Silva et al. 2015). Among the species to accepted in Brazil less than 20% have more than one distribution biome (Rogers & Appan 1973). Among these, there is M. caerulescens, considered the only species of Manihot recorded in the cerrado, caatinga, and Amazon rain forest, which are the three largest Brazilian ecosystems (Allem 2001). This situation, coupled with the small phenotypic alterations mentioned, generated many synonyms for this species. The same is observed for M. anomala, M. carthagenensis and M. tripartita (Rogers & Appan 1973, Allem 1979ac, 1989a).



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CONSERVATION OF WILD RELATIVES SPECIES OF CASSAVA The Manihot species probably originated in the Mesoamericana region and subsequently distributed in South America, colonizing all types of environments (Duputié et al. 2011). The threat level that natural environments are subject to contributes to much of it being on lists of endangered species. The 1997 IUCN Red List of Threatened Plants (Walter & Gillett 1998), includes 65 taxa, between species and subspecies, under various degrees of threat. Recently, just to the northeast of Brazil, 14 species were considered threatened (Martins 2013). Still, the Red Book of Flora of Brazil (Martinelli & Moraes 2013) recognized only M. procumbens Müll. Arg. among the endangered species for the genus, as Vulnerable, highlighting the need for conservation studies for this group. Research on the closest wild relatives of cassava was increased by Duputié et al. (2011). Analysis of molecular phylogeny made from the genes Glyceraldehyde 3-phosphate (G3pdh) and Nitrate Reductase (NIA), showed a clade that includes the subspecies of M. esculenta and 12 other species, among their closest wild relatives. Much of these species needs further study related to their geographical distribution, conservation and taxonomy. Interest in the study of wild relatives of cassava is due to the characteristics of economic interest that these species may hold and can be transferred to cultivated species, this can solve serious problems considered for this culture. The gene pool of these species is threatened due to fragmentation and habitat destruction by deforestation being replaced by agriculture, extensive monoculture pastures and urbanization, and the introduction of exotic species and the influence of climate change (Oliveira 2011). Willis et al. (2007) highlighted several key conservation initiatives, including the identification of endangered species and predictions of species distribution towards future climate change. However, less than 1% of all species on the planet were evaluated to determine their conservation status, i.e., an assessment of the risk of extinction. With increasing loss of biodiversity, it is essential to carry out evaluations on the species conservation status of all groups, thus identifying which of them are at increased risk of genetic erosion, to guide conservation actions. According to Marchioretto et al. (2004), one of the priorities for conservation is obtaining and providing concrete and updated data on the geographical distribution of species. The geographical distribution of a species is a unit resulting from the interaction of factors that act at different intensities and scales as abiotic conditions, biotic interactions, regions that are accessible to the dispersion of species arising from another area and evolutionary capacity of populations to adapt to new environments (Brown 1995, Soberon & Peterson 2005). These characteristics reinforce the need for studies related to the geographical distribution of wild relatives of cassava in order to contribute to their conservation, making taxonomic decisions and direction of collection efforts. In the early twentieth century until World War II, some species were used for extraction of latex for rubber production (Ule 1907, 1914). Currently, however, the search for useful characters is related to improving resistance to pests, diseases and more severe weather conditions such as lack of water and temperature extremes. Such agronomic characteristics can be found among wild relatives of cassava and can be transferred to cultivated species, this can solve problems considered serious for this culture such as whitefly (Aleurotrachelus socialis Bondar), mandarová (Erinnyis ello L.), bacterial blight (Xanthomonas axonopodis pv.


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Manihotis), anthracnose (Colletotrichum gloeosporioides) and African mosaic virus (Fukuda et al. 1999). However, the gene pool of these species is threatened due to fragmentation and destruction of habitat by deforestation process, being replaced by agriculture, extensive monoculture pastures and urbanization, and the introduction of exotic species and the influence of climate change (Oliveira 2011). So one of the priorities for conservation is obtaining and providing concrete and updated data on the geographical distribution of species and their conservation (Marchioretto et al. 2004). Thus, it can summarize the need to develop studies aimed at assessing the status of conservation of wild relatives of cassava due to: 1. Much of the species have been assessed as threatened in unofficial and official lists; 2. Little knowledge of the geographical distribution of most species; 3. Potential use of such species in cassava improvement.

DATA COLLECTION AND ANALYSIS One way to identify the species conservation status is through analytical tools that are available to carry out such assessments. The GeoCAT tool (powered by Google® 2015) performs a geospatial analysis to facilitate the evaluation process, and taxa frame in red lists of endangered species drawn up criteria and categories defined by the IUCN (2014). Those considered the closest wild relatives of M. esculenta were selected primarily for the study of the conservation status of wild species of cassava by Duputié et al. (2011). The data on the occurrence of species distribution were compiled from: 1. Herbarium specimens The herbariums ALCB, ASE, CEN, CEPEC, CPAP, CVRD, EAC, ESA, F, FLOR, FURB, HAS, HB, HPBR, HPUC, HRB, HST, HUEFS, HUFU, HURB, HVASF, IAN, IBGE, ICN, IMA, IPA, IPB, K, MBML, MG, NY, PEUFR, R, RB, SP, SPF, UEC, UFMT, UFP, UFRN, UNB, US, VIC e VIES (Table 1) were consulted and visited ‘in loco’ ‘between 2010 and 2013 or obtained through consultations with the pages of each herbarium in the world wide web based mostly on collections indexed. 2. Harvest data carried out by Embrapa Cassava and Fruit and UFRB. In order to visit the populations referenced by the collections of herbaria and locate new populations, samples were taken in the period between March 2010 and March 2016, in the Brazilian states of Alagoas, Bahia, Espírito Santo, Goiás, Maranhão, Mato Grosso, Minas Gerais, Pará, Paraíba, Pernambuco, Piauí, Rio de Janeiro, Rio Grande do Norte, São Paulo, Sergipe and Tocantins, in areas with a predominance of caatinga, cerrado and tropical rainforest. The collected material also contained leaf samples for DNA extraction, stem segments (cuttings), seeds and seedlings for planting in Germplasm Banks of wild relatives of



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Manihot in EMBRAPA Cassava and Fruit (CNPMF) and Federal University of Bahia Recôncavo (UFRB) in Cruz das Almas, Bahia, Brazil. From the obtained material a pre-selection of herbarium specimens and examined materials was made, excluding those with bad location and duplicate records. Table 1. Consulted herbaria list (acronyms second Thiers 2016) Acronyms of Herbaria ALCB ASE CEN CEPEC CPAP CVRD EAC ESA F FLOR FURB HAS HB HPBR HPUC HRB HST HUEFS HUFU HURB HVASF IAN IBGE ICN IMA IPA IPB K MBML MG NY PEUFR R RB SP SPF UEC UFMT UFP UFPR UFRN UNB US VIC VIES

Nomenclature Herbário Alexandre Leal Costa Herbário da Universidade Federal de Sergipe Herbário da Embrapa Recursos Genéticos e Biotecnologia Herbário do Centro de Pesquisas do Cacau Centro de Pesquisa Agropecuária do Pantanal Companhia Vale do Rio Doce Herbário Prisco Bezerra Herbário da Escola Superior de Agricultura Luiz de Queiroz Field Museum of Natural History Flor Herbarium- Universidade Federal de Santa Catarina Herbário Dr. Roberto Miguel Klein Herbário Alarich Rudolf Holger Schultz Herbário Bradeanum Herbário Padre Balduíno Romba Herbário Pontifícia Universidade Católica de Minas Gerais Herbário Radam Brasil Herbário Sérgio Tavares Herbário da Universidade Estadual de Feira de Santana Herbário Uberlandense Herbário do Recôncavo da Bahia Herbário Vale do Rio São Francisco Herbário da Embrapa Amazônia Oriental Instituto Brasileiro de Geografia e Estatística Herbário do Instituto de Biociências, UFRS Instituto do Meio Ambiente de Alagoas Herbário Dardano de Andrade Lima Instituto Politécnico de Bragança Royal Botanic Gardens Museu de Biologia Professor Mello Leitão Museu Paraense Emilio Goeldi The New York Botanical Garden Universidade Federal de Pernambuco Museu Nacional Herbário Dimitri Sucre Benjamin Instituto de Pesquisas Jardim Botânico do Rio de Janeiro Herbário Maria Eneyda P. K. Fidalgo, Instituto de Botânica de São Paulo Herbário da Universidade de São Paulo Herbário da Universidade Estadual de Campinas Herbário da Universidade Federal de Mato Grosso Herbário da Universidade Federal de Pernambuco Herbário da Universidade Federal do Paraná Herbário da Universidade Federal do Rio Grande do Norte Herbário da Universidade de Brasília Herbário da Universidade de Sevilla Herbário da Universidade Federal de Viçosa Herbário da Universidade Federal do Espírito Santo

We opted for the non-adoption of infraspecific taxa, as this preposition depends on phenotypic studies and population genotypic, which are in early stages of development. The


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only subspecies accepted were those of M. esculenta (M. esculenta subsp. flabellifolia (Pohl) Ciferi and M. esculenta subsp. peruviana (Müll. Arg.) Allem). The primary distribution of 13 species are assessed in Table 2. The georeferencing was assigned by Google Earth 7 tool for herbarium specimens that did not have geographic coordinates to the collection site. Using a checkered mesh 0.5° × 0.5° longitude and latitude and the geographical distribution has been designed in the Neotropics which was divided into 6,818 cells. The ‘status’ of conservation of each species was evaluated from its occurrence Extension (EOO) and Occupation Area (AOO), understanding how EOO area contained within the shortest continuous boundary which can be drawn to encompass all points known, inferred or projected for the actual presence of a taxon, excluding cases of wandering and visitors and as AOO area or the sum of the areas occupied by a taxon within its extent of occurrence (IUCN 2014). Therefore, the distribution data were analyzed by GEOCAT tool (Geospatial Conservation Assessment Tool http://geocat.kew.org/?_ga=1.21973752.216021207. 1461090982) that provides distribution maps with the total area of occurrence and Extension occupation, and automatic categorizing according to the criteria of the International Union for Conservation of Nature (IUCN 2014). The species showed a predominantly central distribution in South America, mainly occupying areas of cerrado and the Amazon rainforest, the Brazilian Central Plateau and Amazon, respectively. Only M. pilosa Pohl showed a concentration in the southeastern region of Brazil, in areas occupied in mostly by deciduous or semideciduous forests and rainforests coastal forests (Figure 10). Conservation status of the species analyzed vary according to the criteria used. The criterion Occupation area (AOO) was less selective in the inclusion of the species most worrying threat levels. Eleven of the 13 analyzed species were considered as Endangered (EN) according to this criterion, with lower occurrence area of 500 km2. Two species (M. marajoara Chermonte de Miranda apud Huber and M. zehntneri Ule) were classified as Critically Endangered (CR) (Table 3). Table 2. Wild relatives of cassava included in the assessment of the conservation status and geographical distribution Espécies M. brachyloba Müll. Arg. M. esculenta subsp. flabellifolia (Pohl) Ciferri M. esculenta subsp. peruviana Müll. Arg. M. flemingiana D. J. Rogers & Appan M. fruticulosa (Pax) D. J. Rogers & Appan M. guaranitica Chodat & Hassl. M. marajoara Chermonte de Miranda apud Huber M. pilosa Pohl M. pruinosa Pohl M. pusilla Pohl M. surinamensis D. J. Rogers &Appan M. tristis Müll. Arg. M. zehntnery Ule

Distribuição Brasil (AC, AM, PA); Caribe Brasil (AC, AM, GO, MA, MT, TO) Brasil (MT, RO); Peru Brasil (AC, GO, MT, RO, TO) Brasil (DF, GO, MG, SP) Brasil (MT); Argentina; Bolívia; Paraguai Brasil (AP, PA) Brasil (ES, MG, RJ, SP) Brasil (GO, MS, MT, TO) Brasil (DF, GO) Guiana; Suriname; Venezuela Brasil (GO, MT, MG, RO, TO); Guiana; Suriname; Venezuela Brasil (BA)


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Table 3. Evaluation of the ‘status’ of current conservation of the species based on the data of this study and comparison with other lists of threatened species (Critically Endangered (E typically five or fewer occurrences or 1,000 or fewer individuals); Danger (typically V- six to twenty occurrences or 1000-3000 individuals); Vulnerable (R-rare, typically 21-100 occurrences or 3,000 to 10,000 people); undetermined (undetermined I-); not in the list of endangered species (S) in Danger. (CR) Critically Endangered; (EN), Vulnerable (VU); Least Concern (LC). AOO (Occupation Area), EOO (Occurrence Extension) Species

IUCN (1997) Status Manihot brachyloba Müll. Arg. S Manihot esculenta subsp. flabellifolia (Pohl) Ciferri S Manihot esculenta subsp. peruviana Müll. Arg. R Manihot flemingiana D. J. Rogers & Appan E Manihot fruticulosa (Pax) D. J. Rogers & Appan V Manihot guaranitica Chodat & Hassl. R* Manihot marajoara Chermonte de Miranda apud Huber R Manihot pilosa Pohl S Manihot pruinosa Pohl S Manihot pusilla Pohl E Manihot surinamensis D. J. Rogers & Appan R Manihot tristis Müll. Arg. E**/R*** Manihot zehntneri Ule E *Manihot guaranitica subsp. boliviana (Pax & K. Hoffm.) D. J. Rogers & Appan. **Manihot tristis subsp. surumuensis (Ule) D. J. Rogers & Appan. ***Manihot tristis subsp. tristis Müll. Arg.

Status AOO EN EN EN EN EN EN CR EN EN EN EN EN CR

Status EOO LC LC LC LC LC LC CR LC LC EN LC LC CR

1. Manihot brachyloba Müll. Arg., Fl. Bras. 11(2): 451. 1874. Common name: Manioc bicha, maniva brava, maniva de veado, sacharumo, yuca cimarrona, yuca de indio, yuca silvestre. Manihot brachyloba is a species predominantly in the Amazon, occurring at the edge of the forest. It Presents an upright shrubby habit or more commonly vine-like, long roots, but not tuberous. There are few records of its occurrence in Central America (Costa Rica and Dominican Republic) that if proven may change their conservation status. Regarded as LC due to the large EOO and EN regarding the AOO, M. brachyloba had not yet been included in any list of endangered species (Figure 3).


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Figure 3. Manihot brachyloba Müll. Arg.: Distribution and Conservation Status according to Extent of Occurrence and Area of Occupancy (Image from Geocat, powered by Google ® 2015).

Regarding criterion Extension Occurrence (EOO), 11 species were considered as LC, M. pusilla EN and the same two species (M. marajoara and M. zehntneri) CR. Unlike the results obtained by each of the criteria it took place probably because of the wide distribution of the species, together with the few records, increasing the potential area of occurrence and consequently its EOO, keeping low, however, the AOO values. Notable species considered Critically Endangered in both criteria, M. marajoara and M. zehntneri, which have complex taxonomic situation, which may have influenced the distribution of records and consequently their categorization front of the conservation status. 2. Manihot esculenta subsp. flabellifolia (Pohl) Ciferri, Arch. Bot. (Forlì) 18: 31. 1942. Common name: Mandioca-brava, mandioca-braba. Manihot esculenta subsp. flabellifolia occurs in the Amazon, in edges of forests and roads with tree vegetation. It has an upright shrubby habit or less rarely vine-like and tuberous roots. It offers potential for use in breeding programs with characteristics related to whitefly resistance, virus African mosaic, bacterial blight, anthracnose and mandarová, besides presenting high content of dry matter and protein (Carabali et al. 2010a, Akinbo et al. 2012). Regarded as LC due to the large EOO and EN regarding the AOO, M. esculenta subsp. flabellifolia has not yet been included in any list of endangered species (Figure 4). 3. Manihot esculenta subsp. peruviana (Müll. Arg.) Allem, Gen. Res. Cap. Ev. 41: 146. 1994. Common Name: Yuquilla. Manihot esculenta subsp. peruviana occurs in the Amazon region, in the northwest portion of South America, on edges of forests and roads with tree vegetation. It has vine-like habit and tuberous roots.



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Regarded as LC due to the large EOO and EN regarding AOO (Figure 5). It was included in the IUCN Red List (1997) as Vulnerable (R).

Figure 4. Manihot esculenta subsp. flabellifolia (Pohl) Ciferri: Distribution and Conservation Status according to Extent of Occurrence and Area of Occupancy (Image from Geocat, powered by Google ® 2015).

Figure 5. Manihot esculenta subsp. peruviana (Müll. Arg.) Allem: Distribution and Conservation Status according to Extent of Occurrence and Area of Occupancy (Image from Geocat, powered by Google® 2015).

4. Manihot flemingiana D. J. Rogers & Appan, Fl. Neotrop. Monogr. 13: 143 1973. Manihot flemingiana occurs in open shrub cerrado areas in the Midwest region of Brazil and in neighboring areas of the Amazon rainforest. It has shrubby habit subshrub and there is no information about its root morphology. Regarded as LC due to the large EOO and EN regarding the AOO (Figure 6). It appears as EN in the IUCN Red List (Walter & Gillet 1998).


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5. Manihot fruticulosa (Pax) D. J. Rogers & Appan, Fl. Neotrop. Monogr. 13: 149. 1973. Manihot fruticulosa occurs open shrub cerrado areas in the central-eastern region of Brazil. It presents subshrub habit, short roots and is not tuberous, but it is edible according to Nassar et al. (2008). Regarded as LC due to the large EOO and EN regarding the AOO (Figure 7). It appears as Endangered (VU) on the IUCN Red List (Walter & Gillet 1998) and as ‘Medium’ risk of extinction second Nassar et al. (2008).

Figure 6. Manihot flemingiana D. J. Rogers & Appan: Distribution and Conservation Status according to Extent of Occurrence and Area of Occupancy (Image from Geocat, powered by Google ® 2015).

Figure 7. Manihot fruticulosa (Pax) D. J. Rogers & Appan: Distribution and Conservation Status according to Extent of Occurrence and Area of Occupancy (Image from Geocat, powered by Google ® 2015).



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6. Manihot guaranitica Chodat & Hassl., Bull. Herb. Boissier II, 5: 671 1905. Common name: Higuerilla, Higuerita. Manihot guaranitica occurs in areas of open cerrado and shrub Chaco South-Central region of South America in Argentina, Bolivia, Brazil and Paraguay. It presents shrubby habit, short roots and it is not tuberous.

Figure 8. Manihot guaranitica Chodat & Hassl.: Distribution and Conservation Status according to Extent of Occurrence and Area of Occupancy (Image from Geocat, powered by Google ® 2015).

The IUCN Red List (Walter & Gillet 1998) includes M. guaranitica subsp. boliviana (Pax & K. Hoffman) D. J. Rogers & Appan as Vulnerable (R). The taxonomic status of this species and its subspecies is undefined and only after revision can its conservation status be evaluated with greater accuracy. At the time, it was decided not to consider the subspecies proposed by Rogers & Appan (1973). Thus, M. guaranitica was considered LC due to the large EOO and EN regarding the AOO (Figure 8). 7. Manihot marajoara Chermonte de Miranda apud Huber, Bol. Mus. Paraense Hist. Nat. 5: 120. 1908. Common name: Mandioca dos Índios, Maniva do Campo. Manihot marajoara occurs in the open areas of northern South America, and in the Brazilian states of Amapá and Pará. It features subshrub habit, short roots and has little tuberous. The 1997 IUCN Red List (Walter & Gillet 1998) includes M. marajoara as Vulnerable (R), however, limited occurrence records could support their inclusion as Critically Endangered (CR) (Figure 9). Gradually records are combined with the fact that their populations are few in number which highlights even more risks. Nevertheless, it is important to say that M. marajoara is closely related to M. surinamensis, with morphological characteristics that may lead to their synonymization, which would alter the status defined here.


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Allem (1980) points out the difficulty of distinguishing M. marajoara and M. surinamensis, which has wider distribution, from Venezuela to Suriname. For the author the differences pointed out by Rogers & Appan (1973) are subtle and weak and may lead them to synonymization. If this occurs, the EOO M. marajoara (older binomial) will be extended by changing their classification.

Figure 9. Manihot marajoara Chermonte de Miranda apud Huber: Distribution and Conservation Status according to Extent of Occurrence and Area of Occupancy (Image from Geocat, powered by Google ® 2015).

8. Manihot pilosa Pohl, PI. Bras. Ic. et Descr. 1: 55. 1827. Common name: Mandioca Brava, Mandioca Braba, Maniva de Veado. Manihot pilosa is distinguished from other species belonging to the same cassava’s clade by having their distribution concentrated in the southeastern region of Brazil, in semideciduous and deciduous forests fragments. It presents shrubby habit tree, extended and tuberous roots like cassava, but more fibrous. Manihot pilosa was considered LC due to the large EOO and EN by AOO (Figure 10). However, it was Considered EN by Nassar et al. (2008). 9. Manihot pruinosa Pohl, PI. Bras. Ic. et Descr. 1: 28. t. 22. 1827. Nome vulgar: Mandioca Braba. Manihot pruinosa has concentrated distribution in the central region of South America, the Midwest of Brazil, and in areas of the woody cerrado. It presents shrubby habit scandent, tuberous roots like cassava, but more fibrous. It was considered by Allem (2002) as one of the closest species of cassava, the so-called ‘primary gene pool’ (GP1) (Figure 1) and therefore one of the most promising in interspecific crosses with cassava. Occurrence Extension data indicate LC while the AOO include it as EN (Figure 11). It can contribute in cassava breeding programs, increasing the nutritional value due to the high protein content that its roots have (Asiedu et al. 1994 Ojulong et al. 2008, Carabali et al. 2010b).



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Figure 10. Manihot pilosa Pohl: Distribution and Conservation Status according to Extent of Occurrence and Area of Occupancy (Image from Geocat, powered by Google ® 2015).

Figure 11. Manihot pruinosa Pohl: Distribution and Conservation Status according to Extent of Occurrence and Area of Occupancy (Image from Geocat, powered by Google ® 2015).

10. Manihot pusilla Pohl, PI. Bras. Ic. et Descr. 1: 36. t. 26. 1827. Manihot pusilla has concentrated distribution in central Brazil, in areas of open shrub Cerrado in Goiás and the Federal District. It is among the smallest species of the genus, with about 30 cm. It has tuberous roots like cassava, but more fibrous. Manihot pusilla was considered EN in both criteria. According to the IUCN Red List (Walter & Gillet 1998) is among the species CR (Figure 12).


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Figure 12. Manihot pusilla Pohl: Distribution and Conservation Status according to Extent of Occurrence and Area of Occupancy (Image from Geocat, powered by Google ® 2015).

11. Manihot surinamensis D.J. Rogers & Appan, Fl. Neotrop. Monogr. 13: 80 1973. Manihot surinamensis is distributed in northern South America, Guyana, Suriname and Venezuela. It is an undergrowth species whose roots have not been investigated. Manihot surinamensis was considered LC due to the large EOO and EN regarding the AOO (Figure 13). According to the IUCN Red List (Walter & Gillet 1998) it was considered VU, but its status may change if synonymized to M. marajoara (see topic on the species). It is likely that the continuation of collecting expeditions in the northern region of South America can contribute to the discovery of more recorded occurrences of this species, contributing to raise the AOO values and consequently changing their conservation status.

Figure 13. Manihot surinamensis D. J. Rogers & Appan. Distribution and Conservation Status according to Extent of Occurrence and Area of Occupancy (Image from Geocat, powered by Google ® 2015).



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12. Manihot tristis Mueller von Argau in Martius, Fl. Bras. 11(2): 449. 1874. Popular name: Boesi-ingi-kasabu, Maynoc, Wilde Cassava, Yuquilla. Manihot tristis has wide distribution in the north central region of South America. It is traditional distributed only to the north of the South American continent (Rogers & Appan 1973), but there are many records for the state of Goiás, and also to Mato Grosso, Minas Gerais, Rondônia and Tocantins, coming from herbarium material identifications made by Antonio Costa Allem, a specialist in the group taxonomy, therefore they were included in the sample. Manihot tristis is a species with complex taxonomy, with great morphological proximity to M. esculenta subsp. flabellifolia and M. leptopoda (Müll. Arg.) D. J. Rogers & Appan, including proposals synonymization the latter species (Allem 1978). It is a shrubby species whose roots have not been investigated. Was considered LC due to the large EOO and EN regarding the AOO (Figure 14). Manihot tristis subsp. surumuensis (Ule) D. J. Rogers & Appan and M. tristis subsp. tristis Müll. Arg. were included in the CR and EN categories respectively in the Red List of IUCN (Walter & Gillet 1998). It declined to consider these subspecies for categorizing effect on the conservation status because of the precariousness of distribution studies and taxonomy of this species. It has whitefly resistance source, the green mite and contains high content of dry matter (Asiedu et al. 1994, Ojulong et al. 2008, Carabali et al. 2010b). Bolhuis (1953) relates to its use as a protein source. These characteristics reinforce its importance in breeding programs, but it is important that it be accompanied by taxonomic studies.

Figure 14. Manihot tristis Müll. Arg. Distribution and Conservation Status according to Extent of Occurrence and Area of Occupancy (Image from Geocat, powered by Google ® 2015).

13. Manihot zehntnery Ule, Bot. Jahrb. Syst. 114: 10. 1914. Manihot zehntneri Ule, referred to the state of Bahia (Rogers & Appan 1973, Nassar et al. 2008, Lamb et al. 2013) was not found in the field, or at least in herbarium collections, with the only record being the holotype. Collected by Zehntner in 1912 (Zehntner 598) in Riacho


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de Santana, Bahia, described by Ule (1914), this species has similarities with the cultivated species M. esculenta Crantz. Rogers & Appan (1973), the holotype photo analysis pointed out this similarity but approximated the species of Glazioviannae Pax emend Rogers & Appan section due to the arboreal habit and its use for rubber extraction, common in the early XX century (Ule 1914). During an expedition held in the city of Riacho do Santana and region there were recorded only individual trees known as “Mandioca de Sete Anos” (Tree Cassava) (Araújo et al. 2001). The characteristics of this material fall on those described by Ule for M. zehntneri and the development of further studies can confirm its relationship to this species and indicate their synonymization M. esculenta. It was regarded as CR in both the analytical approach which supports the categorization of the IUCN Red List (Walter & Gillet 1998) (Figure 15).

Figure 15. Manihot zehntneri Ule. Distribution and Conservation Status according to Extent of Occurrence and Area of Occupancy (Image from Geocat, powered by Google® 2015).

CONCLUSION Only three among the analyzed species presented preliminary studies that suggests valuable features to cassava improvement. They are all strains closely related to M. esculenta, according to latest phylogeny of the genus as M. esculenta subsp. flabellifolia, M. tristis and M. pruinosa, which tends to facilitate the crossing and, consequently, the share of those characteristics with the cultivated species. These characteristics are related to resistance to pests and diseases such as whitefly, African mosaic virus, bacterial blight, anthracnose, green mite and caterpillar ‘mandarová,’ as observed in M. esculenta subsp. flabellifolia and M. tristis. These species are still high dry matter content and the three mentioned species have high protein content in their roots. Some species not included in the analysis do not appear in the same clade M. esculenta also had important features to improve. According to Asiedu et al. (1994), Ojulong et al. (2008), Carabali et al. (2010b) M. reptans Pax has a high protein content, as well as M.



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alutacea D. J. Rogers & Appan, M. falcata D. J. Rogers & Appan, M. paviaefolia Pohl, and M. pentaphylla Pohl (Nassar 1978c). Other species also have potential use as M. glaziovii Müll. Arg. that is resistant to the virus African mosaic, bacterial blight resistance and drought tolerance (Hahn et al. 1980a, 1980b, Ambang et al. 2007, Nassar et al. 2010), M. tripartita (Spreng) Müll. Arg., drought tolerance (Nassar 1978a), M. oligantha Pax, rich in starch, protein and lutein and is resistant to drought, aluminum and cold (Nassar 1978a, 1986) and high content of essential amino acids such as methionine, lysine and tryptophan (Nassar & Sousa 2007), and further, M. dichotoma Ule, which shows high production of roots (Nassar et al. 2004). This fact suggests that these species can also be the subject of breeding programs due to the ease of hybridization seen in the genre. Regarding the conservation status of these species and the discrepancy observed between the occurrence Extension analysis (EOO) and Occupation Area (AOO) has probably given to the precariousness of the data. Regular expeditions of collection of wild species of Manihot, held since 2010 have helped to increase the distribution of data and also to broaden the outlook of each species ‘in loco,’ allowing the verification of their habitat conservation status, the number of individuals of each population, etc. However, expeditions have not yet been made expeditions specifically aimed at the closest relatives of cassava, addressed in this study. Associated with this, it is understood that the increase in studies on the taxonomy of these species can positively affect the categorization regarding the conservation status. Nevertheless, the data measured in this study contributes significantly to the Endangered Species List in Brazil, which so far includes only M. procumbens Müll. Arg., as inconsistent with the timely distribution presented by most species of Manihot and the level of degradation of their ecosystems. It is emphasized that maintaining wild relatives of cassava germplasm bank is a practice of fundamental importance for the improvement of this culture, because the programs rely on the introduction of alleles with valuable agronomic traits contained in these species to minimize the limitations found in culture as pests and diseases.

REFERENCES Akinbo, O., Labuschagne, M. and Fregene, M. (2012). Introgression of whitefly (Aleurotrachelus socialis) resistance gene from F1 inter-specific hybrids into commercial cassava. Euphytica, 183(1): 19-26. Allem, A. C. (1977). Notas taxonômicas e novos sinônimos em espécies de Manihot - I (Euphorbiaceae). Revista Brasileira de Biologia, 37(4): 825–835. [Taxonomical and new notes synonyms in species Manihot - I (Euphorbiaceae). Brazilian Journal of Biology, 37 (4): 825-835.]. Allem, A. C. (1978). Notas taxonômicas e novos sinônimos em espécies de Manihot - II (Euphorbiaceae). Revista Brasileira de Biologia, 38(3): 721–726. [Taxonomical and new notes synonyms in species Manihot - II (Euphorbiaceae). Brazilian Journal of Biology, 38(3): 721–726.].


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Allem, A. C. (1979a). Notas taxonômicas e novos sinônimos em espécies de Manihot - III (Euphorbiaceae). Revista Brasileira de Biologia, 39(3): 545–550. [Taxonomical and new notes synonyms in species Manihot - III (Euphorbiaceae). Brazilian Journal of Biology, 39(3): 545–550.]. Allem, A. C. (1979b). Notas taxonômicas e novos sinônimos em espécies de Manihot - IV (Euphorbiaceae). Revista Brasileira de Biologia, 39(4): 735–738. [Taxonomical and new notes synonyms in species Manihot - IV (Euphorbiaceae). Brazilian Journal of Biology, 39(4): 735–738.]. Allem, A. C. (1979c). Notas taxonômicas e novos sinônimos em espécies de Manihot - V (Euphorbiaceae). Revista Brasileira de Biologia, 39(4): 891–896. [Taxonomical and new notes synonyms in species Manihot - V (Euphorbiaceae). Brazilian Journal of Biology, 39(4): 891–896.]. Allem, A. C. (1980). Notas taxonômicas e novos sinônimos em espécies de Manihot - VI (Euphorbiaceae). Boletim do Museu Botânico Municipal. 40: 1–14. [Taxonomical and new notes synonyms in species Manihot - VI (Euphorbiaceae). Bulletin Municipal Botanical Museum, 40: 1–14.]. Allem, A. C. (1989a). Four new species of Manihot (Euphorbiaceae) from Brazil. Revista Brasileira de Biologia, 49(3): 649–662. Allem, A. C. (1989b). A Revision of Manihot section Quinquelobae (Euphorbiaceae). Revista Brasileira de Biologia, 49(1):1–26. Allem, A. C. (1999). A new species of Manihot (Euphorbiaceae) from the Brazilian Amazon. International Journal of Plant Sciences, 160: 181–187. Allem, A. C. (2001). Three New Infraspecific Taxa of Manihot (Euphorbiaceae) from the Brazilian Neotropics. Novon, 11(2): 157-165. Allem, A. C. (2002). Cassava: biology, product and utilization. In The origins and taxonomy of Cassava (Hillocks, R. J.; Thresh, J. M. and Bellotti, A. C., eds.). Natural Resources Institute, Greenwich. p. 1–16. Allem, A. C. (1999). The closest wild relatives of cassava (Manihot esculenta Crantz). Euphytica 107: 123–133. Asiedu, R., Hahn, S. K., Vijaya Bai, K. and Dixon, A. G. O. (1994). Interspecific hybridization in the genus Manihot-progress and prospects. Acta Horticulturae, 380: 110–113. Bai, K. V., Asiedu, R. and Dixon, A. G. O. (1993). Cytogenetics of Manihot Species and Interspecific Hybrids. In: W.M. Roca & A.M. Thro (Eds.), Proc First Intl Sci Meet 19 Cassava Biotechn Netw, pp. 51–55. Cartagena, Colombia, 25–28 August 1992. Centro Internacional de Agricultura Tropical, Cali, Colombia, 1993. CIAT Working Document n.123. Barroso, G. M., Amorim, M. P., Peixoto, A. L. and Ichaso, C. L. F. (1999). Frutos e sementes. Morfologia aplicada à sistemática de dicotiledôneas. Editora UFV, Universidade Federal de Viçosa. 443p. [Fruits and seeds. Morphology applied to the system of dicots. UFV, Viçosa Federal University. 443p.]. Bauhin, J. (1651). Historia plantarum universalis. 2: 794. Berry, P. E., Hipp, A. L., Wurdack, K. J., Van Ee, B. and Riina, R. (2005). Molecular phylogenetics of the giant genus Croton and tribe Crotoneae (Euphorbiaceae sensu stricto) using ITS and trnL-trnF DNA sequence data. American Journal of Botany. 92: 1520–1534.



399

Bolhuis, G. G. (1953). A survey of some attempts to breed cassava varieties with a high content of protein in the roots. Euphytica. 20: 107–112. Bomfim, N. N., Graciano-Ribeiro D. and Nassar N. M. (2011). Genetic diversity of root anatomy in wild and cultivated Manihot species. Genetic and Molecular Research. 10(2): 544–51. Carabalí, A., Bellotti, A. C., Montoya-Lerma, J. and Fregene, M. (2010a). Manihot flabellifolia Pohl, wild source of resistance to the whitefly Aleurotrachelus socialis Bondar (Hemiptera: Aleyrodidae). Crop Protection. 29(1): 34–38. Carabalí, A., Bellotti, A. C., Montoya-Lerma, J. and Fregene, M. (2010b). Resistance to whitefly, Aleurotrachelussocialis, in wild populations of cassava, Manihot tristis. Journal of Insect Science, 10(170): 1–10. Carmo-Jr, J. E., Sodre, R. C., Silva, M. J. da & Sales, M. F. (2013). Manihot (Euphorbiaceae s.s.) no Parque Estadual da Serra Dourada, Goiás, Brasil. Rodriguésia, 64: 727–746. [Manihot (Euphorbiaceae s.s.) in Golden Hill State Park, Goiás, Brazil. Rodriguésia, 64: 727–746.]. Carvalho, R. and Guerra, M. (2002). Cytogenetics of Manihot esculenta Crantz (cassava) and eight related species. Hereditas. 136: 159–168. Chacon, J., Madriñan, S., Debouck, D., Rodriguez, F. and Tohme, J. (2008). Phylogenetic patterns in the genus Manihot (Euphorbiaceae) inferred from analyses of nuclear and chloroplast DNA regions. Molecular Phylogenetics and Evolution, 49: 260–267. Colombo, C., Second, G. and Charrier, A. (2000). Diversity within American cassava germoplasm based on RAPD markers. Genetics and Molecular Biology. 31(1): 189–199. Cordeiro, I., Secco, R., Silva, M. J. da, Sodré, R. C. and Martins, M. L. L. Manihot. Lista de Espécies da Flora do Brasil. Jardim Botânico do Rio de Janeiro. 2014 [Manihot. Species List of Flora of Brazil. Rio de Janeiro Botanical Garden]. (04 jul 2016). Available from URL: http://floradobrasil.jbrj.gov.br/jabot/floradobrasil/ FB17591. Corrêa, A. M. S., Barros, M. A. V. C, Silvestre-Capelato, M. F. S., Pregun, M. A., Raso, P. G. and Cordeiro, I. (2010). Flora polínica da Reserva do Parque Estadual das Fontes do Ipiranga (São Paulo, Brasil). [Flora pollinic of Ipiranga Sources State Park] Hoehnea. 37(1): 53–69. Croizat, L. (1943). Preliminari per uno Studio Del genere Manihot nell' America Meridionale. Revista Argentina de Agronomia. 10(3): 213–226. [Preliminary study of genus Manihot of southern America. Argentina Journal of Agronomy. 10(3): 213–226.]. Cruz, N. D. (1968). Citologia no gênero Manihot Adans. I. Determinação do número de cromossomos em algumas espécies. Annais Academia Brasileira de Ciências. 40: 91-95. [Cytology in the genus Manihot Adans. I. Determination of the number of chromosomes in some species. Annals of Brazilian Academy of Sciences. 40: 91–95.]. Cruz-Barros, M. A. V., Corrêa, A. M. S. and Makino-Watanabe, H. (2006). Estudo polínico de Aquifoliaceae, Euphorbiaceae, Lecythidaceae, Malvaceae, Phytolaccaceae e Portulacaceae ocorrentes na restinga da Ilha do Cardoso (Cananéia, SP, Brasil). Revista Brasileira de Botânica. 29: 145-162. [Pollinic study by Aquifoliaceae, Euphorbiaceae, Lecythidaceae, Malvaceae, Phytolaccaceae and Portulacaceae occurring in the sandbank of Cardoso Island (Cananéia, SP, Brazil). Brazilian Journal of Botany. 29: 145–162.]. Cunha-Neto, I. L., Martins, F. M. Caiafa, A. N. and Martins, M. L. L. (2014). Leaf anatomy as subsidy to the taxonomy of wild Manihot species in Quinquelobae section (Euphorbiaceae). Brazilian Journal of Botany, 37: 481–494.


400


Daniell, H., Wurdack, K. J., Kanagaraj, A., Lee, S. B., Saski, C. and Jansen, R. K. (2008). The complete nucleotide sequence of the cassava (Manihot esculenta) chloroplast genome and the evolution of atpF in Malpighiales: RNA editing and multiple losses of a group II intron. Theoretical Applied Genetics. 116: 723–737. Dehgann, B. (1984). Phylogenetic significance of interspecific hybridization in Jatropha (Euphorbiaceae). Systematic Botany, 9: 467–478. Dunstan, W. R., Henry, T. A. and Auld, S. J. M. (1906). Cyanogenesis in Plants. Part V. The Occurrence of Phaseolunatin in Cassava (Manihot aipi and Manihot utilissima). Proceedings of the Royal Society of London. B. 78: 152–158. Duputié, A., Salick, J. and McKey, D. (2011). Evolutionary biogeography of Manihot (Euphorbiaceae), a rapidly radiating Neotropical genus restricted to dry environments. Journal of Biogeography. 1: 1–11. FAO. Food and Agriculture Organization of the United Nations. 2015 (06 jan 2016). Available from: URL: http://faostat3.fao.org/faostat-gateway/go/to/download/Q/QC /E. Fukuda, W. M. G., Cavalcanti, J., Fukuda, C. and Costa, I. R. S. (1999). Variabilidade genética e melhoramento da mandioca (Manihot esculenta Crantz). In: Recursos Genéticos e Melhoramento de Plantas para o Nordeste Brasileiro. 1 ed. Petrolina. 14p. [Genetic variability and improvement of cassava (Manihot esculenta Crantz). In: Genetic Resources and Plant Breeding for the Brazilian Northeast. 1 ed. Petrolina. 14p.]. Graciano-Ribeiro, D., Hashimoto, D. Y., Nogueira, L. C & Teodoro, D. (2009). Internal phloem in an interspecific hybrid of cassava, an indicator of breeding value for drought resistance. Genetic and Molecular Research. 8: 1,139-1,146. Graciano-Ribeiro, D., Nassar, N. M. A., Hashimoto, D. Y. C & Miranda, S. F. (2008). Anatomy of polyploid cassava and its interspecific hybrids. Gene Conserve. 7: 620–635. Grattapaglia, D., Nassar, N. M. A. and Dianese, J. C. (1987). Biossistemática de espécies brasileiras do gênero Manihot baseada em padrões de proteína de semente. Ciência & Cultura. 39: 294–300. [Biosystematics of species of the genus Manihot based on seed protein patterns. Science & Culture. 39: 294-300.]. Halsey, M. E., Olsen, K. M., Taylor, N. J. and Chavarriaga-Aguirre, P. (2008). Reproductive Biology of Cassava (Manihot esculenta Crantz) and Isolation of Experimental Field Trals. Crop Science, 48: 49–58. Hans A. S. (1973). Chromosomal conspectus of the Euphorbiaceae. Taxon. 22: 591–636. Hassal, D. C. (1976). Numerical and Cytotaxonomic Evidence for Generic Delimitation in Australian Euphorbieae. Australian Journal of Botany. 24: 633–40. Hayirlioglu-Ayaz, S., Huseyin, I. and Beyazoglu, O. (2002). Cytotaxonomic studies on some Euphorbia L. (Euphorbiaceae) species in Turkey. Pakistan Journal of Botany. 34(1): 27– 31. IUCN International Union for Conservation of Nature (1997). Red List of Threatened Plants. Magnoliopsida. Compiled by the World Conservation Monitoring Center. IUCN - The World Conservation Union, Gland, Switzerland and Cambridge, UK. 862pp.

IUCN International Union for Conservation of Nature. Guidelines for using the IUCN red list categories and criteria, ver. 1.1. 2014 (02 may 2016). Available from: URL: http:www.iucnredlist.org/documents/RedListGuidelines.pdf Jennings, D. L. (1959). Manihot melanobasis Müll. Arg. – A useful parent for cassava breeding. Euphytica 8: 157–162. Jennings, D. L. and Iglesias C. (2002). Breeding for crop improvement. In: Cassava biology,



401

production and utilization (Hillocks RJ, Tresh JM and Belloti AC, eds.). CAB International, Wallingford, Oxon, 149-166. Jennings, D. L. (1963). Variation in pollen and ovule fertility in varieties of cassava, and the effect of interspecific crossing on fertility. Euphytica. 12: 69–76. Kulju, K. K. M., Sierra, S. E. C. and Van Welzen, P. C. (2007). Reshaping Mallotus [Part 2]: inclusion of Neotrewia, Octospermum and Trewia in Mallotus s.s. (Euphorbiaceae s.s.). Blumea. 52: 115–136. Leitch, A. R., Lim, K.Y., Leitch, I. J., O.Neill, M., Chye, M. and Low, F. (1998). Molecular cytogenetic studies in rubber, Hevea brasiliensis Muell. Arg. (Euphorbiaceae). Genome. 41: 464–467. Léotard, G., Duputié, A., Kjellberg, F., Douzery, E., Debain, C., de Granville, J. J. and McKey, D. (2009). Phylogeography and the origin of cassava: new insights from the northern rom of the Amazonian basin. Molecular Phylogenetics and Evolution. 53: 329– 334. Machado, I. C. S., Barros, L. M. and Sampaio, E. V. S. B. (1997). Phenology of caatinga species at Serra Talhada, PE, Northeastern Brazil. Biotropica. 29: 57–68. Magoon, M. L., Krishnan, R. and Vijayabai, K. (1970). Cytogenetcs of the F. hybrid between cassava and ceara rubber and its back crosses. Genetica. 41: 3-12. Majumder, S. K. (1964). Studies on the germination pollen of Hevea brasiliensis in vitro and on artificial media. Journal of the Rubber Research Institute of Malaysia. 18: 185–193. Marchioretto, M. S, Windisch, P. G. and Siqueira, J. C de (2004). Padrões de distribuição geográfica das espécies de Froelichia Moench e Froelichiella R. E. Fries Amaranthaceae) no Brasil. Iheringia, Sér. Bot., Porto Alegre, 59(2): 149–159. Martinelli, G. and Moraes, M. A. (Orgs.). (2013). Livro Vermelho da Flora do Brasil. 1ªEd. Rio de Janeiro: Andrea Jacoksson: Instituto de Pesquisas Jardim Botânico do Rio de Janeiro. 1,100p. [Red Book of Flora of Brazil. 1ªEd. Rio de Janeiro: Andrea Jacoksson: Research Institute Botanical Garden of Rio de Janeiro. 1,100p.]. Martins, M. L. L. (2013). Avanços taxonômicos em Manihot Mill. para o Brasil. PhD Thesis, Universidade Estadual de Feira de Santana. [Taxonomic advances in Manihot Mill. to Brazil. PhD Thesis, University of Feira de Santana.]. Martins, M. L. L. and Ledo, C. A. S. (2015). Manihot cezarii (Euphorbiaceae), a new species from Central-Western of Brazil. Novon. 24: 179–181. Martins, M. L. L., Carvalho, P. C. L. and Amorim, A. M. A. (2011). A remarkable Manihot (Euphorbiaceae) from the coastal sand plains of Sergipe, Brazil. Phytotaxa. 32: 57–60. Martins, M. L. L., Carvalho, P. C. L., Ledo, C. A. S. and Amorim, A. M. A. (2014). What’s New in Manihot Mill. (Euphorbiaceae)? Systematic Botany. 39(2): 485–489. Mendoza, J. M. (2013). Manihot (Euphorbiaceae) en Bolivia, parte I: Tres especies nuevas y un nuevo registro. Brittonia. 38: 42–57. [Manihot (Euphorbiaceae) in Bolivia, Part I: Three new species and a new record. Brittonia. 38: 42-57.]. Mendoza, J. M. (2010). Los parientes silvestres del cultivo de la Yuca (casaba) en Bolivia: estado de conocimiento, grado de conservación y acciones de conservación propuestas. La Paz: Imprenta Sagitário. 142 p. [Wild relatives of cassava in Bolivia: state of knowledge, degree of conservation and proposed conservation actions. La Paz: Printing Sagittarius. 142 p.].


402


Mendoza, J. M., Simon, M. F. and Cavalcanti, T. B. (2015). Three new endemic species of Manihot (Euphorbiaceae) from the Chapada dos Veadeiros, Brazil. Arnaldoa. 22: 297– 312. Miller, K. I. and Webster, G. L. (1966). Chromosome Numbers in the Euphorbiaceae. Brittonia. 18(4): 372–379. Müller, A. (1873–1874). Euphorbiaceae. In.: Martius, C.F.P. and Eichler, A.G., Flora Brasiliensis. Monachii et Lipsiae. 11(2): 292. Müller, J. (1866). Euphorbiaceae exceto subordo Euphorbieae. In: A. P. De Candolle (ed.). Prodromus Systematics Universalis Regni Vegetabilis. 15: 189–1,286. Nassar, H. N. M. and Freitas, M. (1997). Prospects of polyploidizing cassava, Manihot esculenta Crantz, by unreduced microspores. Plant Breeding. 116: 195–197. Nassar, N. M. A. and Souza, M. (2007). Amino acid profile in cassava and its interspecific hybrid. Genetics and Molecular Research, 6: 92–197. Nassar, N. M. A. (1978a). Conservation of the genetic resources of cassava (Manihot esculenta): determination of wild species localities with emphasis on probable origin. Economic Botany. 32: 311–320. Nassar, N. M. A. (1978b). Hydrocyanic acid content in some wild Manihot (cassava) species. Canadian Journal of Plant Science. 58: 577–578. Nassar, N. M. A. (1978c). Microcenters of wild cassava Manihot spp. Diversity in Central Brazil. Turrialba. 28: 345–347. Nassar, N. M. A. (1979a). A study of the collection and maintenance of the germplasm of wild cassavas Manihot spp. Turrialba. 29: 221–221. Nassar, N. M. A. (1979b). Three Brazilian Manihot species with tolerance to stress conditions. Canadian Journal of Plant Science. 59: 533–555. Nassar, N. M. A. (1980). Attempts to hybridize wild Manihot species with cassava. Economic Botany. 34: 13–15. Nassar, N. M. A. (1982). Collecting wild cassavas in Brazil. Indian Journal of Genetic. 42: 405–411. Nassar, N. M. A. (1984). Natural hybrids between Manihot reptans Pax and M. alutacea Rogers & Appan. Canadian Journal of Plant Science. 64: 423–425. Nassar, N. M. A. (1985). Manihot neusana Nassar: a new species native to Paraná, Brazil. Canadian Journal of Plant Science. 65: 1,097–1,100. Nassar, N. M. A. (1986). Genetic variation of wild Manihot species native to Brazil and its potential for cassava improvement. Field Crops Research. 13: 177–184. Nassar, N. M. A. (2000a). Cassava, Manihot esculenta Crantz genetic resources: Their collection, evaluation, and manipulation. Advances in Agronomy. 69: 179–230. Nassar, N. M. A. (2000b). Cytogenetics and evolution of cassava (Manihot esculenta Crantz). Genetic and Molecular Biology. 23: 1,003–1,014. Nassar, N. M. A. (2000c). The transference of apomixis genes from Manihot neusana Nassar to cassava, Manihot esculenta Crantz. Hereditas 132: 167–170. Nassar, N. M. A. (2002). Keeping options alive and threat of extinction: a survey of wild cassava survival in its natural habitats. Gene Conserve. 1: 10. Nassar, N. M. A. (2003). Gene flow between cassava, Manihot esculenta Crantz, and wild relatives. Genetics Molecular Research. 4(2): 334–347.



403

Nassar, N. M. A. (2006). Mandioca: Uma opção contra a fome estudos e lições do Brasil e do mundo. Ciência Hoje, 39(231): 31–34. [Cassava: An option against hunger studies and lessons from Brazil and the world. Science Today, 39 (231): 31-34.] Nassar, N. M. A. Hashimoto, D. Y. C. and Fernandes, S. D. C. (2008). Wild Manihot species: botanical aspects, geographic distribution and economic value. Genetics and Molecular Research. 7(1): 16–28. Nassar, N. M. A., Alves, J. and Souza, E. (2004). UnB 033: An interesting interspecific cassava hybrid. Revista Ceres. 51(296): 495–499. Nassar, N. M. A., Bomfim, N., Chaib, A., Abreu, L. F. A. and Gomes, P. T. C. (2010). Compatibility of interspecific Manihot crosses presaged by protein electrophoresis. Genetics and Molecular Research. 9(1): 107–112. Neves, E. L., Funch, L. S. and Viana, B. F. (2010). Comportamento fenológico de três espécies de Jatropha (Euphorbiaceae) da Caatinga, semi-árido do Brasil. Revista Brasileira de Botânica. 33: 155–166. [Phenological behaviour of three species of Jatropha (Euphorbiaceae) Caatinga, semi-arid region of Brazil. Brazilian Journal of Botany. 33: 155–166.]. Nowicke, J. W. (1994). A palynological study of Crotonoideae (Euphorbiaceae). Annals of the Missouri Botanical Garden 81: 245–269. Ojulong, H., Labuschangne, M., Herselman, L. and Fregene, M (2008). Introgression of genes for dry matter content from wild cassava species. Euphytica. 164(1): 163–172. Oliveira, M. M. de. Diversidade genética em espécies silvestres e híbridos interespecíficos de Manihot. 2011. 86 f. MSc. Dissertation (Agricultural Sciences) – Centro de Ciências Agrárias, Ambientais e Biológicas. Universidade Federal do Recôncavo da Bahia. 2011. [Genetic diversity of wild species and interspecific hybrids of Manihot. 2011. 86 f. MSc Dissertation (Agricultural Sciences) – Centre of Agricultural Sciences, Environmental and Biological. Federal University of Reconcavo of Bahia. 2011.]. Oliveira‚ J. H. G. and Oliveira‚ D. M. T. (2009). Morphology‚ anatomy and ontogeny of the pericarp of Manihot caerulescens Pohl and M. tripartita Müll. Arg. (Euphorbiaceae). Revista Brasileira de Botânica. 32(1): 117–129. Olsen, K. M. and Schaal, B. A. (1999). Evidence on the origin of cassava: Phylogeography of Manihot esculenta. Proceedings of the National Academy of Sciences. 96: 5,586–5,591. Olsen, K. M. (2002). Population history of Manihot esculenta (Euphorbiaceae) inferred from nuclear DNA sequences. Molecular Ecology. 11: 901–911. Olsen, K. M. and Schaal. B. A. (2001). Microsatellite variation in cassava (Manihot esculenta Euphorbiaceae) and its wild relatives: further evidence for a southern Amazonian origin of domestication. American Journal of Botany, Missouri, 88(1): 131–142. Orlandini, P. and Lima, L. R. (2014). Sinopse do gênero Manihot Mill. (Euphorbiaceae) no Estado de São Paulo, Brasil. Hoehnea. 41: 51–60. Pax, F. (1910). Manihot Adans. In:Engler, Pflanzenreich IV. 147(Heft 44): 21–111. Pohl, J. (1827). Plantarum Brasiliae Icones et Descriptiones. 1: 17–56. Punt, W. (1962). Pollen morphology of the Euphorbiaceae with special reference to taxonomy. Wentia. 7: 1–116. Reich, P. B., Uhl, C., Walters, M. B., Prugh, L. and Ellsworth, D. S. (2004). Leaf demography and phenology in Amazonian rain forest: A census of 40000 leaves of 23 tree species. Ecology Monograph. 74: 3–23.


404


Roa, A. C., Maya, M. M., Duque, M. C., Tohme, J., Allem, A. C. and Bonierbale, M. W. (1997). AFLP analysis of relationships among cassava and other species. Theoretical and Applied Genetics. 95: 741–750. Rodrigues, A. S. (2007). As tribos Dalechampieae Müll. Arg. e Manihotae Melchior (Euphorbiaceae) no Distrito Federal, Brasil. Dissertation (Mestrado em Botânica), Universidade de Brasília. 104p. [The tribes Dalechampieae Müll. Arg. and Manihotae Melchior (Euphorbiaceae) in the Federal District, Brazil. Dissertation (MSc. Botany), University of Brasilia. 104p.]. Rogers, D. J. and Appan, S. G. (1973). Manihot and Manihotoides (Euphorbiaceae): A Computer Assisted Study. Flora Neotropica (Monograph No. 13). Hafner Press, New York. 272p. Rós, A. B., Hirata, A. C. S., Araújo, H. S. and Narita, N. (2011). Crescimento, fenologia e produtividade de cultivares de mandioca. Pesquisa Agropecuária Tropical. 41(4): 552– 558. [Growth, phenology and productivity of cassava cultivars. Journal of Tropical Agriculture. 41(4): 552–558.]. Rudall, P. (1994). Laticifers in Crotonoideae (Euphorbiaceae): Homology and Evolution. Annals of the Missouri Botanical Garden. 81(2): 270–282. Sasikala R. and Paramathma M. (2010). Chromosome studies in the genus Jatropha L. Electronic Journal of Plant Breeding. 1: 637–642. Satiro, L. N. and Roque, N. (2008). Levantamento da família Euphorbiaceae Juss. nas caatingas arenosas do Médio São Francisco. Acta Botanica Brasilica. 22(1): 99–118. [Family survey Euphorbiaceae Juss. in the sandy scrublands of the Middle São Francisco. Acta Botanica Brasilica. 22(1): 99–118.]. Silva, M. J. da (2016). Manihot gratiosa and M. lourdesii spp. nov. (Manihoteae, Euphorbiaceae) from the Brazilian Cerrado. Nordic Journal of Botany. 34: 66–74. Silva M., Sodré R. C. and Almeida L. C. S. (2013). A new endemic species of Manihot (Euphorbiaceae s. str.) from the Chapada dos Veadeiros, Goiás, Brazil. Phytotaxa. 131 (1): 53–57.\ Silva, M. J. (2015). Manihot appanii (Euphorbiaceae s.s.) a New Species from Brazil, and a Key to the Species with Unlobed or Very Shortly Lobed Leaves. Systematic Botany. 40: 168–173. Soberon, J. and Peterson, A. T. (2005). Interpretation of Models of fundamental ecological niches and species' distributional areas. Biodiversity Informatics. 2: 1–10. Steudel, E. T. (1840, 1841). Nomenclator Botanicus. Part I, 1,840, p. 779–800; Part II, 1,841, p. 99. Tannus, J. L. S., Assis, M. A. and Morellato, L. P. C. (2006). Fenologia reprodutiva em campo sujo e campo úmido numa área de Cerrado no sudeste do Brasil, Itirapina -SP. Biota Neotropica. 6(3): 1–27. [Phenology in dirty field and wet field in a Cerrado area in southeastern Brazil, Itirapina SP. Biota Neotropica. 6 (3): 1–27.]. Thiers, B. [continuously updated]. Index Herbariorum: A global directory of public herbaria and associated staff. New York Botanical Garden's Virtual Herbarium. Available from: URL: http://sweetgum.nybg.org/ih/. Tokuoka, T. and Tobe, H. (2002). Ovules and seeds in Euphorbioideae (Euphorbiaceae): structure and systematic implications. Journal of Plant Research. 115: 361–374. Ule, E. (1907). Vorläufi ge Mitteilung über drei noch unbeschriebene Kautschui liefernde Manihot-Arten in Bahia. Notizblatt Königl Botanischen Gartens und Museums zu Berlin-



405

Dahlem. 41: 119. [Preliminary Communication about three undescribed rubber supplying cassava species in Bahia. Notepad Royal Botanical Gardens and Museum in BerlinDahlem. 41: 119.]. Ule, E. (1914). Beitrage zur Kenntnis der brasilianischen Manihot-Arten. Beiblatt zu den Botanischen Jahrbuchern. 5: 1–12. [Contributions to the knowledge of Brazilian cassava species. Supplement to the Botanical year Bookers. 5: 1–12.]. Walter, K. S. and Gillett, H. J. 1997 IUCN Red List of Threatened Plants. Compiled by the World Conservation Monitoring Centre. IUCN - The World Conservation Union, Gland, Switzerland and Cambridge, UK. lxiv, 1998, 862p. Webster, G. L. (1958). A monographic study of the West Indian species of Phyllanthus. Journal of Arnold Arboretum. 39: 111–212. Webster, G. L. (1994). Synopsis of the genera and suprageneric taxa of Euphorbiaceae. Annals of Missouri Botanical Garden. 81: 33–144. Willis, K. J., Araujo, M. B., Bennett, K. D., Figueroa-Rangel, B., Froyd, C. A. and Myerl, N. (2007). How can a knowledge of the past help to conserve the future? Biodiversity conservation and the relevance of long-term ecological studies. Philosophicall Transactions of the Royal Society B-Biological Sciences. 362: 175–186.



INDEX # 16S rRNA gene, xiii, 231, 235

A agbelima, 321, 322, 330 amylopectin, 5, 30, 102, 118, 153, 275, 300, 303, 338, 342, 343 amylose, 5, 30, 93, 94, 118, 153, 275, 300, 302, 303, 307, 338, 342, 343 ash, xiv, xv, 15, 20, 106, 110, 154, 271, 274, 275, 281, 286, 287, 298, 299, 336, 337, 339, 343, 347, 352, 377

B bacterial universal primers, 235 bacteriocin, xiii, 231, 237, 238, 239, 241, 242 beta- glucosidase, xiii, 231 bioethanol, 3, 4, 22, 23, 24, 25, 26, 27, 28, 131, 132, 135, 136, 138, 139, 140, 141, 143, 144, 145, 146, 147, 160, 169, 173, 175, 182, 183, 184, 185, 197, 252, 260, 266, 267, 268, 285, 286, 293, 331 bio-fertilizer, 131, 134, 135, 137, 139 biofortified cassava, 108 biofuels, vii, xi, 1, 5, 6, 16, 24, 25, 28, 130, 157, 158, 160, 171, 174, 182, 183, 184, 192, 194, 195, 256, 331, 353, 355 biogas, x, 129, 131, 133, 134, 135, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 175, 179, 180, 181, 182, 186, 187, 188, 189, 190, 194, 196, 198, 199, 260 bio-hydrogen, x, 129, 131, 133, 134, 136, 137, 144 bioprocesses, xi, 149, 152, 161, 174, 186, 190, 196

bioproducts, xi, 22, 149, 150, 151, 156, 157, 158, 159, 160, 161, 171, 174, 175, 192, 197, 269, 309 biosurfactants, xii, 158, 172, 173, 174, 175, 177, 178, 192, 193, 194, 195, 196, 197 bitter cassava, 107, 108, 175, 263, 273, 298 bivariate probit model, ix, 56, 57, 60, 61, 62, 66, 70, 73, 75, 81

C calcium, vii, xi, 13, 15, 20, 29, 30, 90, 91, 106, 124, 152, 153, 171, 176, 232, 241, 248, 253, 276, 304, 306 Caldicellulosiruptor saccharolyticus, 137, 144 Caloramator boliviensis, 146, 185, 197 carbohydrate, 5, 30, 91, 97, 99, 132, 169, 175, 180, 193, 232, 252, 272, 274 carotenoids, xi, 107, 108, 149, 159, 161, 168, 169 cassava peel, xiii, xv, 114, 130, 132, 140, 143, 180, 181, 192, 231, 232, 233, 234, 236, 237, 244, 246, 247, 248, 313, 318, 322, 324, 325, 326, 327, 328, 329, 331, 332 cassava processing waste, x, 129, 131, 132, 139, 145, 153, 167, 194, 199 cassava production, viii, ix, xiv, 35, 36, 41, 42, 43, 44, 46, 55, 56, 57, 63, 72, 81, 82, 139, 152, 202, 203, 207, 209, 210, 211, 212, 213, 214, 232, 272, 294, 313, 314, 315, 317, 328, 358 cassava residue, xiv, 142, 176, 313, 324, 329 cassava wastewater, xi, xiii, 144, 152, 155, 156, 157, 158, 162, 171, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 184, 185, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 199, 231, 233, 234, 236, 243, 245, 246, 247 chipping, 280, 318, 319, 323 classification, 3, 107, 108, 175, 272, 347, 375, 376, 380, 392


408

Index

color, x, 95, 98, 100, 106, 107, 111, 116, 155, 264, 280, 281, 282, 304 composition, x, xi, xiv, 5, 6, 11, 12, 16, 18, 20, 30, 87, 88, 93, 94, 97, 100, 101, 103, 106, 109, 124, 132, 133, 138, 141, 145, 150, 152, 153, 154, 156, 157, 159, 162, 171, 172, 173, 174, 175, 176, 191, 192, 199, 259, 271, 273, 275, 280, 281, 282, 283, 284, 286, 291, 292, 293, 294, 295, 298, 324, 338, 339, 340, 342, 343, 347, 353, 354, 355 cooking conditions, 132 copper, 106, 152, 153, 166, 176, 196, 232, 246, 253, 276 culture dependent molecular method, 234 cyanogenic glycosides, 90, 107, 108, 155, 232, 233, 237, 272

323, 324, 325, 326, 327, 328, 329, 330, 331, 332, 333 fibers, 106, 116, 172, 176, 184, 254, 255, 262, 266, 267, 269, 284, 288, 304, 305, 307, 310 films, xiv, 173, 254, 255, 262, 263, 264, 265, 267, 268, 269, 279, 297, 298, 300, 301, 302, 307, 308, 309, 311, 312, 355 first and second-generation fuel ethanol, 2 foams, xiv, 297, 298, 302, 303, 304, 305, 306, 307, 308, 309, 310, 354 frying/drying/roasting, x, xvi, 34, 43, 105, 108, 109, 113, 114, 116, 118, 119, 123, 151, 162, 218, 280, 281, 300, 306, 318, 319, 320, 321, 322, 358

D

gari, xii, xiv, 130, 201, 202, 203, 204, 206, 207, 208, 209, 210, 211, 212, 220, 245, 248, 291, 293, 294, 313, 314, 320, 321, 322, 329, 360 gelatinization, 8, 12, 92, 111, 114, 118, 122, 279, 300, 305, 309, 310 genomic DNA, 234 Ghana, vi, xiv, 36, 53, 248, 292, 294, 313, 314, 315, 316, 317, 318, 319, 320, 321, 322, 328, 329, 330, 331, 332 glutamate synthase, xiii, 231, 238, 239, 241 grating, 34, 107, 111, 114, 219, 318, 319, 320, 323

diseases, viii, xvi, 30, 32, 35, 36, 40, 41, 49, 88, 104, 131, 160, 272, 294, 317, 323, 373, 383, 396, 397 DNA-binding protein, 237, 238, 243, 244

E eco-materials, 297 enzyme, 7, 9, 14, 27, 34, 36, 136, 141, 144, 147, 219, 236, 237, 241, 245, 246, 248, 258, 261, 268, 277, 323, 325, 326, 327, 331 ethanol, v, 1, 2, 3, 8, 16, 17, 20, 23, 25, 27, 28, 34, 135, 137, 139, 142, 162, 182, 244, 256, 257, 268, 285, 325, 326, 329, 330, 331, 332

F farinha d' água, 111, 112, 113, 116, 117, 118 farm size categories, 56, 61, 68, 72, 73, 203, 207, 208, 211 fat, 93, 97, 99, 100, 106, 253, 298, 299 fed-batch, 136, 139, 141, 144, 146, 158, 166, 168, 185, 325, 326, 329 fermentation, x, xiv, 7, 8, 9, 10, 11, 13, 15, 16, 17, 19, 20, 21, 24, 25, 26, 27, 28, 92, 105, 110, 112, 113, 116, 118, 119, 120, 123, 129, 131, 135, 136, 137, 139, 140, 141, 142, 143, 144, 145, 146, 151, 152, 157, 163, 167, 168, 169, 173, 175, 179, 180, 181, 182, 183, 184, 185, 186, 188, 190, 191, 192, 193, 194, 196, 197, 198, 199, 218, 229, 233, 237, 244, 245, 246, 247, 253, 257, 258, 260, 267, 268, 271, 272, 275, 277, 278, 280, 281, 285, 288, 289, 290, 291, 292, 293, 294, 295, 318, 319, 320, 321,

G

H harvesting, viii, 29, 31, 33, 34, 35, 44, 109, 110, 131, 137, 258, 265, 272, 275, 281, 314, 318, 327 hectares, 75, 157, 314 HQCF, 35, 228, 322 Hydrocyanic Acid, 107 hydroxynitrile lyase, xiii, 231, 237, 238

I improved cooking, 132 industrial cassava, 108 iron, xi, 36, 91, 106, 108, 109, 124, 135, 143, 152, 153, 171, 232, 276, 320

K kokonte, xiv, 313, 321, 322, 323, 329


409

Index

L

P

lactic acid, xii, xiv, xv, 116, 134, 163, 172, 179, 180, 187, 195, 196, 198, 232, 233, 246, 259, 271, 272, 277, 288, 289, 290, 291, 294, 295, 303, 313, 324, 327, 328, 329, 330, 331, 333, 337 Lactobacillus plantarum, xiii, 179, 180, 181, 194, 199, 231, 233, 236, 237, 238, 242, 293, 323, 328, 331, 332 linamarin, 34, 107, 114, 124, 155, 219, 237, 272, 273, 298, 323 lipid, 106, 158, 189, 193, 199, 253, 274, 284, 285 lotaustralin, 34, 107, 272, 273, 323

packaging, xiii, 93, 212, 243, 251, 254, 262, 263, 264, 266, 269, 297, 298, 303, 305, 306, 308, 337, 360 peel, 133, 152, 184, 232, 233, 236, 237, 255, 324, 326, 327, 336 peeling, xv, 107, 108, 114, 118, 119, 151, 152, 175, 273, 283, 284, 318, 320, 322, 323, 335, 337 peplication protein, 238, 243 phosphorus, vii, 29, 32, 33, 90, 91, 106, 124, 135, 145, 152, 158, 189, 199, 232, 315 plasmid DNA, xiii, 231, 235 poly-glutamic acid, xiii, 231, 248 potassium, xi, 32, 33, 91, 106, 135, 152, 156, 171, 232, 295 pretreatment step, vii, 1, 2, 8, 13, 18 profitability, ix, 15, 36, 55, 56, 57, 58, 62, 72, 73, 74, 78, 81 protein, vii, ix, xi, xiii, xiv, xv, xvii, 12, 20, 21, 22, 29, 30, 34, 35, 36, 87, 89, 90, 91, 93, 94, 97, 99, 100, 106, 124, 130, 133, 139, 152, 154, 160, 171, 176, 193, 218, 219, 229, 231, 232, 233, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 249, 253, 259, 264, 269, 271, 272, 274, 275, 276, 280, 281, 282, 284, 285, 286, 287, 289, 291, 298, 299, 303, 304, 313, 323, 324, 329, 330, 374, 388, 392, 395, 396, 397, 399, 400, 403

M magnesium, xi, 106, 152, 171, 232, 276 manganese, 91, 106, 134, 135, 232 maniçoba, 124 Manihot glaziovii, 140, 141, 143, 144, 145, 146, 147, 197, 273, 293 manipueira, xi, 115, 123, 149, 150, 151, 155, 156, 158, 165, 166, 198 Manipueira, xi, 123, 149 Maniva, 124, 391, 392 metric tonnes, 4, 314, 328, 358 microalgae, xi, 149, 150, 151, 158, 159, 160, 161, 166, 168, 169, 189, 194, 199 modern technology adoption, ix, 56, 77, 81 moisture, x, 10, 16, 30, 51, 91, 97, 99, 105, 106, 110, 111, 112, 116, 119, 121, 123, 151, 153, 156, 175, 191, 232, 250, 254, 255, 263, 266, 279, 280, 284, 285, 286, 298, 299, 301, 303, 304, 305, 306, 319, 320, 324, 359

N niacin, 106 Nigeria, v, vi, viii, ix, xi, xii, xiii, 29, 30, 31, 35, 36, 37, 38, 39, 40, 53, 55, 56, 57, 58, 59, 61, 62, 67, 68, 72, 74, 75, 78, 81, 82, 83, 84, 85, 90, 104, 106, 130, 139, 140, 146, 150, 166, 171, 186, 201, 202, 203, 207, 209, 211, 212, 213, 214, 220, 228, 229, 231, 234, 245, 247, 249, 265, 274, 281, 283, 291, 330, 359

O organic acids, xii, 152, 163, 172, 173, 175, 179, 180, 181, 182, 187, 188, 193, 198, 233, 285

R riboflavin, 106, 324 RNA chaperones, 243

S sieving, 12, 13, 151, 318, 320, 322 site-specific recombinase, 240, 242, 243 sodium, 106, 136, 167, 232 spherical granules, 121 sugarcane bagasse, vii, 1, 2, 7, 8, 11, 16, 17, 18, 19, 20, 21, 22, 24, 26, 27, 28, 145, 245, 304, 309, 310, 353 sweet cassava, 104, 107

T table cassava, 108 tannase, xiii, 231, 236, 237, 238, 245, 246, 247, 248


410

Index

tapioca, x, 34, 50, 91, 105, 108, 109, 110, 111, 112, 120, 121, 122, 123, 126, 127, 152, 162, 185, 186, 198, 202, 220, 279, 298, 309, 314, 360 tapioca starch, 108, 152, 185, 186, 198, 279, 309 Thermotoga neapolitana, 137, 144 thiamine, 106 Thioredoxin, 243 tucupi, x, 105, 106, 108, 115

V vitamin A, 36, 40, 106, 107, 127, 324 vitamin B, 106 vitamin C, 90, 106, 124 vitamins, vii, xi, 29, 30, 35, 88, 106, 149, 152, 274, 324 volatile fatty acids, xii, 172, 190

W wastewater, v, vi, x, xi, 129, 143, 144, 149, 150, 151, 152, 155, 156, 157, 158, 160, 161, 162, 163, 166, 167, 168, 169, 171, 173, 174, 175, 176, 177, 179, 180, 181, 182, 184, 185, 186, 188, 189, 190, 191, 192, 193, 194, 195, 196, 198, 199, 233, 234, 236, 245, 247, 248, 260

Z zinc, xi, 106, 108, 135, 143, 171, 196, 232, 243, 249, 276
