Production of Bioethanol from Selected Lignocellulosic Agrowastes

Abstract

This study evaluated the ability of cassava peels, banana peels, orange peels and corn cobs hydrolysates to produce bioethanol. Fibre fractions analysis was carried out using standard methods. The samples were pre-treated with acid and base, followed by simultaneous saccharification and fermentation (SSF) for bioethanol production. During fermentation, pH, total titratable acidity, reducing sugar, microbial load and bioethanol yield were determined. The reducing sugar yield for Aspergillus niger and Bacillus cereus were 30.28 g and 13.35 g for corn cobs. The pH was observed to decrease during fermentation period with orange peels having the lowest pH of 2.6 after 240 hours of fermentation using A. Niger and S. cerevisiae, when B. cereus and S. Cerevisiae were used the pH was observed to be 4.10.  Total titratable acidity showed increase in all the substrates, with corn cobs having the highest when B. cereus and S. cerevisiae were used (1.62), followed by cassava peels when A. niger and S. cerevisiae were used (1.52). Highest ethanol yield following simultaneous saccharification and fermentation with A. niger and S. cerevisiae was obtained in corn cobs with 17.43 g/100 g, while orange peels gave the lowest with 8.02 g/100 g, the ethanol yield from each substrates as well as the combined substrates were significantly different at p≤ 0.05. The combined substrates (1:1:1:1) gave the highest ethanol yield of 12.44 g/100 g using A. niger and S. cerevisiae.  This study therefore revealed that A. niger had the highest bioethanol yield using corn cobs as the carbon source, therefore it could be used for mass bioethanol production.