Comparative Studies on Bioethanol Production from Some Starch Based Agricultural Waste Peels

Abstract

The potential of some starch-based agricultural waste peels (cassava peels, yam peels and potato peels) for bioethanol production was investigated. They were pretreated with physico-chemical agents before being hydrolyzed using cellulase enzymes from the Trichoderma ressei micro-organism. Using co-cultures of Saccharomyces cerevisiae and Pichia stipitis fermentative yeasts, the different hydrolysates were fermented to bioethanol. The bioethanol yields of separate hydrolysis and co-fermentation (SHCF) and simultaneous saccharification and co-fermentation (SSCF) fermentative procedures were evaluated. The maximum bioethanol yields from the fermentation results for cassava peels, yam peels and potato peels were 4.87, 3.78 and 5.31 (% w/v wet biomass) respectively after 72 hours of fermentation. The SSCF method was shown to be more successful since it produced higher bioethanol yields in all of the substrates studied and was quicker. When compared to prior research using different microorganisms, the SSCF technique had a superior fermentation yield using mixed cultures of Trichoderma ressi, Saccharomyces cerevisiae and Pichia stipites.