BRIX PRODUCTION FROM CASSAVA PEELS AND OPTIMIZATION OF BIOETHANOL SYNTHESIS USING SACCHAROMYCES CEREVISIAE

Abstract

The purpose of this paper is to produce and optimize brix from cassava peels for bioethanol production using Saccharomyces cerevisiae. The use of agricultural waste products in bioethanol production helps in decreasing reliance on food crops. Optimization of production medium is required to maximise metabolite yield. The capacity of Saccharomyces cerevisiae to ferment wort derived from cassava peels, an agricultural waste, in optimized conditions to produce bioethanol, was investigated. 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 was subjected to physical and biological pretreatments to obtain simple 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 1.7 oBx to 3.8 oBx while bioethanol production ranged from 1.01g/l to 2.29g/l. At optimal conditions of pH 8, temperature of 33oC, inoculum size of 3, substrate weight of 20g and fermentation time of 119h, predicted ethanol yield will be 3.67g/l. Cassava peel is a good substrate for bioethanol production. Higher yield of bioethanol was realised with optimization of the fermentation medium.

Keywords

• optimization
• agricultural waste products
• brix
• bioethanol
• response surface methodology