This study investigated the production of bioethanol from unripe plantain peels in an optimized condition. Optimization of production medium maximises metabolite yield. Reliance on food crops is reduced when agricultural waste products are used to produce bioethanol. The capacity of Saccharomyces cerevisiae to ferment wort derived from unripe plantain peels, an agricultural waste, in optimized conditions to produce bioethanol, was studied. A box-behnken design of five factors (substrate weight, temperature, inoculum size, pH, incubation time) and three levels was adopted to improve production efficiency. The substrate (unripe plantain peels) was subjected to physical and biological pretreatments to obtain simple sugars. Cellulase enzyme was used to breakdown the substrate to simpler sugars. Alcoholic fermentation was done using S. cerevisiae for six days. Brix content was measured before and during the fermentation process, as well as alcohol content after fermentation. Response surface plots of the factors were plotted. The results showed that brix value ranged from 0.5 oBx to 2.0 oBx while bioethanol production ranged from 0.2g/l to 1.1g/l. At optimal conditions of pH 6, temperature of 40oC, inoculum size of 5, substrate weight of 20g and fermentation time of 75h, predicted ethanol yield will be 1.3g/l with maximum concentration of brix as 2.2 oBx. 1.3g/l of bioethanol was realized with optimization of the fermentation medium. The peel of unripe plantains is a good substrate for the synthesis of bioethanol.
Offor-Emenike et al. (Fri,) studied this question.