International Journal of Modern Chemistry, 2012, 1(1): 1-8 International Journal of Modern Chemistry

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1 International Journal of Modern Chemistry, 2012, 1(1): 1-8 International Journal of Modern Chemistry Journal homepage: IJMChem.aspx ISSN: Florida, USA Article Comparative Studies on the Preparation of Bio-ethanol from Cassava (Mannihot esculenta Crantz) and Maize (Zea mays L) 1 Ubwa, S.T., 2 Nwadinigwe, C.A, 1 Ugalahi-Igbum, G.O. and 1,* Anhwange, B.A 1 Department of Chemistry, Benue State University Makurdi, Nigeria 2 Department of Pure and Industrial Chemistry, University of Nigeria, Nsukka * Author to whom correspondence should be addressed; banhwange@yahoo.com Article history: Received 6 January 2012, Received in revised form 18 January 2012, Accepted 19 January 2012, Published 20 January Abstract: A comparative studies on production of bio-ethanol from crops like maize (Zea mays L) and Cassava (Mannihot esculenta Crantz) was determined. Maize seeds were milled while cassava tubers were peeled and grated. The milled and grated starchy materials were subjected to liquefaction and saccharification using proteolytic enzymes (Bioprotease), α-amylases (Hitempase and Fungamyl) and glucoamylase (amyloglucosidase, (AMG) and the starch in these materials converted to fermentable sugars. Fractional and simple distillation processes were employed to convert the fermented sugars to dry bio-ethanol. The results showed that bioprotease (0.32g and 0.64g) produced highest volumes 65.00cm 3 and 92.67cm 3 of bio-ethanol from cassava and maize respectively. Similarly 0.16g and 0.64g produced 90.58% and 91.46% from cassava and maize respectively. Modified route produced highest volumes, 75.17cm 3 and 113cm 3 of bio-ethanol from cassava and maize respectively. The highest purity 93.03% and 63.18% was obtained at 1.90g and 0.27g of hitempase from cassava and maize respectively. Fungamyl (1.21g and 0.11g) produced 63cm 3 and 94.33cm 3 from cassava and maize respectively. Similarly, 0.43g of fungamyl produced highest purity 90.51% and 91.51% from cassava and maize respectively. Amyloglucosidase (AMG) (0.45g) produced 72.17cm 3 and 96.67cm 3 from cassava and maize respectively. Also, (0.23g and 0.45g) produced highest purity, 90.15% and 92.13% from cassava and maize respectively. The results showed that maize is a better feedstock for production of bio-ethanol. Keywords: Cassava, Maize, Bio-protease, Hitempase, Fumgamyl, AMG. 1. Introduction It is been projected that global oil reserves will last at least 44 years. Undiscovered oil that is thought to exist might last another years. Instead of remaining at the current level, however,

2 2 global oil consumption is projected to increase significantly in the next few years. This will hasten the depletion of global oil reserves (Colin et al, 1998). The estimated oil resources of today are fast depleting because of their finite (non-renewable) nature. There is the need to look for an alternative source which will be replenishable within a short time. Besides wind and hydropower, the use of biomass has tremendous future especially bio-fuel. According to Tulloch (2011), bio-fuels are renewable, clean burning fuels, degradable and have considerably environmentally friendly potential. Bio-fuels made from crops grown in the subtropics and tropics (such as corn, cassava), show very high energy efficiency. For some bio-fuels (like ethanol made from corn) the energy balance may even be negative. Productivity of some crops such as cassava, maize and millet in developing countries like Nigeria has declined over past years because of lack of market for them. If farmers in these countries become energy-producing farmers, who sell bio-fuels on the international market, their incomes would increase substantially, in this sense, the bio-fuels opportunity offers a way to lower the indirect impacts of poverty on the people (Kulp et al 2000). Bio-ethanol is produced from a variety of renewable agricultural feedstock, including grains such as corn, wheat and tubers such as cassava, sweet potatoes and forestry residues. It is an important value-added market for farmers. The rural economies will receive a tremendous boost if necessary crop for production of bio-ethanol are produced (De Keyser et al, 2005). The use of bio-ethanol has a potential for reducing the dependency on fossil fuels whose exploration and exploitation has brought about environmental degradation resulting in increased militancy in places like Niger Delta region of Nigeria with attendant negative effects on the economy. This has necessitated the need to look for ways of substituting conventional fuels (fossil fuels) by biofuels to reduce pollution, conserve/increase foreign earnings, support sustainable agriculture and empower rural farmers (Ned, 2010). The feedstock (Agricultural products), cassava (Mannihot esculenta, Crantz) and maize (Zea mays, L) used in production of bio-ethanol are produced in large quantities in the study area but suffer a lot of loss at post harvest due to lack of market and storage facilities. This research seeks to establish which feedstock will be a better option for production of bio-ethanol using a modified route. 2. Materials and Methods 2.1 Sampling The study areas selected were Guma, Gwer West and Gboko Local Government Areas of Benue State, Nigeria.

3 3 The three Local Government Areas were designated as sampling stations and they were labeled as A m (maize), B c, and D c (cassava), (Table 1) based on the item sampled respectively. A total of three samples were collected from three biggest markets of each sampling station. The sampling was carried out between April and November during the harvest period of the crops. The samples were identified by a botanist in the Department of Biological Sciences, Benue State University Makurdi. The samples were collected in polythene bags and kept in a dry place for analysis. All enzymes, yeasts and other reagents were provided by Benue Brewery Limited (BBL), Makurdi. Table 1. Sampling Guide S/N Sampling Stations Sample No of Samples 1. Guma (A m ) Maize 3 2. Gwest West (B c ) Cassava 3 3. Gboko (D c ) Cassava 3 Total number of samples Preparation of samples Starch materials used were from cereal grains (maize) and tubers (cassava). The processing steps for the two categories of starch materials above differ at some stages. Processing of Maize Milling: The maize samples were milled and prepared for liquefaction, saccharification and fermentation. All procedures adopted for analysis were those described by BBL and Matthewson. A modified route was also used for the analysis (Mathewson, 1980). Fractional distillation: The beer was subjected to fractional distillation and bio-ethanol collected at 78 o C. Specify gravity: Specific gravity of bio-ethanol was determined according to BBL method. Drying of bio-ethanol: Drying of bio-ethanol was carried out using the method described by Coble (1981). Determination of purity of bio-ethanol: The percentage purity of the bio-ethanol was determined by comparing the specific gravity of the bio-ethanol produced with the standard values given by Helrich (1990). The same processes were repeated by changing the concentrations of the various enzymes used by halving and doubling them. 2.3 Production of bio-ethanol from maize using a modified route

4 4 Concentrations of enzymes used here were the same as in BBL method, except that for hitempase, where g and g, were used at initial and final gelatinization temperatures of maize respectively. Liquefaction, saccharification, drying and specific gravity determination were done as previously discussed. 2.4 Processing of Cassava tubers Cassava tubers were peeled, washed and grated and production of bio-ethanol for (B c and D c ) were carried out using BBL and Mathewson s methods as earlier described for maize. 3. Results and Discussions 3.1 Effect of variation of feedstock and concentration of bioprotease on bio-ethanol production volume of bio-ethanol distillate obtained Maize: Using maize (corn) as a feedstock, and a concentration of bioprotease 0.64g (2BBL value), the highest volume obtained was cm 3 and the lowest 89.67cm 3 was obtained from 0.16g. Cassava: The highest volume produced was 65cm 3 from 0.32g and the lowest volume, 60.83cm 3 at the concentration of 0.16g (Table 2). Statistical analysis showed no significant variation in volume of distillate at different bioprotease concentration Table 2. Mean Volume Distillates and Percentage Purity of Feedstock with Bioprotease Concentration of Bioprotease Feedstock BBL (0.32g) Double BBL(0.64g) Half BBL (0.16g) Volume % Purity Volume % Purity Volume % Purity Cassava Maize Percentage Purity Maize (Corn): The highest purity, 91.46% was obtained at 0.64g (2BBL value) and the lowest purity, 90.08%, at 0.16g.

5 5 Cassava produced the highest purity, 90.58% at 0.16g of bioprotease (0.5BBL value) and the lowest purity, 90.51% at 0.32g of bioprotease (Table 2). There was no significant variation in volume of distillate at different bioprotease concentrations. 3.2 Effect of variation of feedstock and concentration of hitempase on production of bioethanol volume of bio-ethanol distillate obtained Maize: The highest volume, 113cm 3 was distilled when the modified route was used and the lowest, 90.67cm 3 at 0.54g of hitempase. Cassava: The highest volume, 75.20cm 3 was distilled when the modified route was used and the lowest volume, 61.50cm 3 was obtained at the concentration of 0.27g of hitempase (Table 3). Statistical analysis showed significant variation in the volume of bio-ethanol distillate at different concentrations of hitempase. Table 3. Mean Volume Distillates and Percentage Purity of Feedstock with Hitempase Concentration of Hitempase Feedstock BBL (0.54g) Double BBL(1.09g) Half BBL (0.27g) Modified Route Volume % Purity Volume % Purity Volume % Purity Volume % Purity Cassava Maize Purity of bio-ethanol produced Maize: The highest purity, 93.18% was obtained when the concentration of hitempase was 1.09g, 0.27g and the lowest, 90.20% when 0.54g of hitempase was used. Cassava: The highest purity, 93.03% was obtained at the concentration of 1.09g of hitempase and the lowest, 90.51% at the concentration of 0.54g of hitempase and the modified route. Statistical analysis showed significant variation in the percentage purity of bio-ethanol at different concentrations of hitempase. 3.3 Effect of variation of feedstock and fungamyl concentration on production of bio-ethanol Volume of bio-ethanol distillate obtained

6 6 Maize: The highest volume, 94.33cm 3 was distilled when 0.11g of fungamyl was used. The lowest volume, 90.67cm 3 was distilled at 0.21g of fungamyl. Cassava: The highest volume, 65cm 3 was distilled at 0.21g of fungamyl and the lowest volume, 61.33cm 3 at 0.43g of fungamyl (Table 4). Statistical analysis showed no variation in the volume of bioethanol at different concentrations of fungamyl. Table 4. Mean Volume Distillates and Percentage Purity of Feedstock with Fungamyl Concentration of Fungamyl Feedstock BBL (0.21g) Double BBL(0.43g) Half BBL (0.11g) Volume % Purity Volume % Purity Volume % Purity Cassava Maize Percentage purity of bio-ethanol produced Maize: The highest purity, 91.51% was obtained at 0.43g of fungamyl and the lowest volume, 90.20% at 0.21g. Cassava: The highest purity, 93.03% was obtained at 0.43g of fungamyl and the lowest purity, 90.51% at 0.21g of fungamyl (Table 4). Statistical analysis showed no significant variation in the percentage purity at different concentrations of fungamyl. 3.4 Effect of variation of feedstock and Amyloglucosidase (AMG) concentration on production of bio-ethanol Volume by bio-ethanol distillate Maize: The highest volume, 96.67cm 3 was obtained at 0.45g of AMG and the lowest, 88cm 3 at 0.11g of AMG. Cassava: Volume distilled was highest, 72.17cm 3 at 0.45g of AMG and the lowest, 61.50cm 3 at 0.11g of AMG (Table 5). Statistical analysis showed significant variation in the volume of bio-ethanol distillate at different concentrations of AMG.

7 7 Table 5. Mean Volume Distillates and Percentage Purity of Feedstock with Amyloglucosidase (AMG) Concentration of (AMG) Feedstock BBL (0.21g) Double BBL(0.43g) Half BBL (0.11g) Volume %Purity Volume %Purity Volume %Purity Cassava Maize Percentage purity of bio-ethanol produced Maize: The highest purity, 92.13% was obtained at 0.45g of AMG and the lowest, 89.43% at 0.11g of AMG. Cassava: The highest purity, 90.51% was obtained at 0.23g of AMG and the lowest, 90.40% at 0.11g (Table 5). Statistical analysis showed a significant variation in the percentage purity of bio-ethanol produced at different concentrations of AMG. 4. Conclusion Variation in concentration of enzyme especially Hitempase and AMG affected the volume of bio-ethanol distillate and percentage purity. The bio-ethanol analysed from the maize and cassava using the modified route produced the highest volumes, though the volume and purity determined from maize were higher than those of cassava. This implies that maize is a better feedstock for production of bio-ethanol than cassava. References [1] Coble, C.G., Hiler, E.A., Sweeten, J.M., O Neal, H.P., Reidenback, V.G., Lepori, W.H., Schelling, G.T., and Kay, R.D. Small scale ethanol production from cereal feedstocks, In Cereals; A Renewable Resource (Y. Pomeranz and L. Munck, eds), American Associations of Cereal Chemists, St. Paul, MN, 1981, P [2] Colin J. Campbell and Jean H. Laherrere. The End of Cheap Oil, accessed on 2nd January, [3] De Keyser, S and Hongo, H. Farming for energy for better livelihoods in Southern African FELISA. Paper Presented at the PfA-TaDO Policy Dialogue Conference on the Role of Renewable Energy for Poverty Alleviation and Sustainable Development in Africa, Dar-es-Salaam, 22 June, Copyright 2012 by Modern Scientific Press Company, Florida, USA

8 8 [4] Helrich, K. Official methods of analysis of the Association of official Analytical Chemist. Suite 400, 2200 Wilson Boulevard Arlington, Virginia 2220, USA. 1990, Vol. 1 and 2. [5] Kulp,K and J.G. Ponte. Handbook of Cereal Science and Technology Marcel Dekker, Inc.New York, 2000, p790. [6] Mathewson, S.W. The manual for home and farm production of alcohol fuel: Ten speed press, J.A. Diaz Publication, 1980, p94. [7] Ned Haluzan, Biofuels advantages and disadvantages, html [8] Tulloch James. Raising the Next Generation, Copyright 2012 by Modern Scientific Press Company, Florida, USA