Production of Bioethanol from Corn Cob Hydrolysate

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Addis Ababa University


All societal activities depend up on energy services to meet the daily. The environmental issues, the growing demand for energy, increasing petroleum-based oil prices and the depletion of petroleum created the need for the development of sustainable and safe alternative energy source. Bioethanol is one of the alternative energy sources. In this study of ethanol production from corn cob dilute sulfuric acid method of hydrolysis was employed because it is easy and productive process. The samples were mixed with distilled water in a ratio of 1:10 (w/v) and pretreated using 1% dilute sulfuric acid in autoclave at temperature of 120℃ for 30 minutes. It was hydrolyzed using diluted H2SO4 of 2%, 3% and 4% at a temperature of (100 ℃, 120 ℃ and 140 ℃) for (20, 30 and 40) minutes. Sugar concentrations were determined using phenol sulfuric acid method. The maximum, medium and minimum sugar yields were 53.56536, 47.46514 and 41.64815 g/l respectively. Fermentation was conducted using the hydrolysates(sugars) obtained in previous process, inoculum level of (5, 10, 15 %v/v) and temperature of (25, 30, 35 ℃) for 72 hours. Sugar concentration and inoculum level have a statistically significant effect on ethanol yield with pvalue of 0.0021 and 0.0068 respectively. Ethanol yield was maximum at middle values of the fermentation parameters and it is negatively affected at their minimum and maximum values. From the statistical analysis maximum ethanol yield of 0.530 mL/g was found at sugar of 4.917 g, inoculum of 12.17 %v/v, and at a temperature of 29.977 ℃ with 89.8 % desirability. In FTIR, it was observed that the ethanol produced from corn cob contains O-H functional group, C-O, CH2, and CH3 groups. Finally, a good yield of ethanol was obtained. So, corn cob is a potential feedstock for ethanol production.



Bioethanol, Corn cob, saccharomyces cerevisiae, glucose equivalent, Pretreatment, Hydrolysis, Fermentation, FTIR