Optimization of Chemical Pre-Treatment of Cassava Bagasse for Reducing Sugar and Bioethanol Production

Abstract

Background: The indiscriminate litter of agricultural wastes which cause environmental menace and the increased interest in alternative sources of energy have led to the exploration of agro-waste as potential low cost and efficient bioproduct raw material.

Aims: This study investigated the effect of different pre-treatment solvents in the use of cassava bagasse as feedstock for reducing sugar and ethanol production in saccharification and fermentation (SSF) processes.

Methods: Cassava tubers were peeled and processed to extract starch, with the resultant waste dried to obtain cassava bagasse (CB). The CB was subjected to various chemical treatments which include hydrothermal, Hp? H?S04' NaOH, combined C2HpH with H2S04, and combined C2HpH with NaOH. Pre-treated CB that gave the high cellulose-yield were further subjected to enzymatic saccharification using crude enzyme extract of Tricoderma viride and Aspergillus niger prior to anaerobic production of ethanol by fermentation in the presence of commercial yeast.

Results: Pre-treatment resulted in significant (p<0.05) CB weight loss and increased cellulose yield compared to the unpretreated bagasse. Amongst the pre-treatment groups, H2S04pre-treatment gave the highest cellulose yield (92.30±0.27%). Saccharification with crude enzyme of viride and A. niger co-culture released significant (p<0.05) reducing sugar from the pre-treated CB slurries after24 hours. However, fermentation of the pre-treatedCB gave significant(p<0.05) lower ethanol yield compare to the unpretreated.

Conclusion: The present study indicates the potential use of tropical isolates and local agro-waste as raw materials for bio production of reducing sugar and ethanol. Findings of this research suggest that the production of bio-products of interest determine the pre-treatment condition even with the same raw material base.