Production of bioethanol from cassava and sweet potato peels

Abstract

The enzymatic production of Bioethanol from cassava and sweet potato peels was examined using two groups of organisms. Gloeophyllum sepiarium and Pleurotus ostreatus were used to hydrolyse 20g, 35g and 50g of substrates at 280C for 7 days. Zymomonas mobilis and Saccharomyces cerevisiae were further used to ferment the substrates at 280C for 5 days. The fermented liquid was distilled at 780C and quantity of ethanol produced determined. When both G. sepiarium and P. ostreatus were used for hydrolysis and both Z. mobilis and S. cerevisiae were used for fermentation, 50g of cassava peel and 50g of sweet potato peel yield 11.97g/cm3 (26%) and 6.5g/ cm3 (12%) of ethanol respectively. When only Z. mobilis was used for fermentation, the mass of bioethanol produced from cassava peels and sweet potato peels were 10.6g/cm3 (23%) and 5.9g/cm3(12%) respectively and when only S. cerevisiae was used for fermentation, the mass of bioethanol produced from cassava peels and sweet potato peels were 10.36g/cm3 (22%) and 5.68 g/cm3 (12%) respectively. When 35g of substrate was used, cassava peel had a yield of 9.64g/ cm3 (20%) while sweet potatoe peel had a yield of 5.3g/cm3 (10%). When 20g of substrate was used, cassava peel had a yield of 7.8g/ cm3 (14%) while sweet potatoe peel had a yield of 4.66g/cm3 (9%). The study revealed that bioethanol can be produced from cassava and sweet potato peels with maximum yield obtained using Gloeophyllum sepiarium and Pleurotus ostreatus for hydrolysis and Zymomonas mobilis and Saccharomyces cerevisiae for fermentation.