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| dc.contributor.author | Henok, Mesfin Tadesse | |
| dc.date.accessioned | 2024-09-01T10:12:50Z | |
| dc.date.available | 2024-09-01T10:12:50Z | |
| dc.date.issued | 2024-03 | |
| dc.identifier.uri | http://ir.bdu.edu.et/handle/123456789/15936 | |
| dc.description.abstract | In this research work, production of bioethanol from a mixture of lignocellulosic biomass brewers’ spent grain (BSG) and sugarcane molasses was investigated to find the optimum conditions that would enable to reduce the overall manufacturing expenses and maximize the process yield. The BSG underwent a microwave-assisted alkaline hydrogen peroxide pretreatment conducted at optimal operating conditions identified after conducting experiments designed according to central composite design, whereas the molasses, being a nonlignocellulosic sugar-rich feedstock, was not pretreated. The pretreatment was carried out with 4% v/v H2O2 solution having a pH of 11.5 at solid to liquid ratio of 0.1 or 10% w/v solid loading. The process was optimized by conducting experiments under varying operating parameters, microwave power (MW) (A, 100 – 500 Watt) and MW irradiation time (B, 2 – 10 min.) in terms of lignin removal (L, %) as a response variable and the optimal conditions were found to be 282.25 Watt and 7.27 min respectively. Optimization of the dilute phosphoric acid hydrolysis conditions was performed as well. A central composite design with response surface methodology was employed to design the experiments and optimize the process involving three independent variables; acid concentration (A, 2 – 4% v/v), hydrolysis time (B, 20 – 60 min.) and molasses mixing proportion (C, 0 –50% w/w) and the response variable, reducing sugar concentration (R, g/l), determined by Di-nitro salicylic acid (DNSA) method. The optimal conditions obtained were an acid concentration of 3.16% v/v, hydrolysis time of 42.5 min. and molasses mixing proportion of 38.1% w/w. Bioethanol was produced by applying the optimum operating conditions identified and undergoing fermentation of the resulting hydrolysate for 72 hours using Saccharomyces cerevisiae and subsequently conducting simple distillation on the fermentation liquor. The resulting product was then characterized by running FTIR spectroscopy to analyze the recorded spectra and by conducting density, viscosity and flash point tests on the product. The concentration of the produced bioethanol was determined by potassium dichromate method was 39.34% v/v. The overall yield of the conversion process of BSG was found to be 0.28 grams of bioethanol per gram of dry BSG. Key words: Bioethanol, lignocellulose, optimization, pretreatment, hydrolysis, BSG and sugarcane molasses. | en_US |
| dc.language.iso | en_US | en_US |
| dc.subject | Chemical and Food Engineering | en_US |
| dc.title | Production and optimization of bioethanol from brewers’ spent grain and sugarcane molasses mixture utilizing Saccharomyces cerevisiae | en_US |
| dc.type | Thesis | en_US |
