Optimization of fermentation condition for bio ethanol production from corn cobs

Abstract

Lignocellulosic biomass can be utilized to produce ethanol, a promising alternative energy Source for petroleum based fuels. The bioconversion of lignocellulosic to bio fuel from cheap non edible materials such as corn cob for renewal energy is very important. Corn cobs are abundant, inexpensive, reusable, contains sufficient amount of cellulosic material, which is the best source of fermentable sugars. In this study, corn cobs were mechanically treated followed by drying, acidic hydrolysis and alcoholic fermentation. In this paper, optimization of fermentation process by Response Surface Methodology (RSM) was performed using Box behnken design. The process here in included physical and chemical pre-treatment of biomass, which was then followed by acid hydrolysis as a potential step. The concentration of reducing sugar in the hydrolyzate thus obtained was then analyzed by Benedict solution. After fermenting the hydrolysate with Saccharomyces cerevisiae for several days, distillation was done. Analysis of hydrolysate was done by FTIR. Pre-treatment is used for lignocellulosic biomass for improving the hydrolysis of the corn cob as it contains a high amount of cellulose and removal of lignin and hemicellulose. Cellulose is converted into the reducing sugars and then to ethanol. Distillation and fermentation process were performed to acquire maximum yield of ethanol. The corn cob was pre-treated with Sulphuric acid and sodium hydroxide solutions. Different parameters of fermentation conditions were optimized. The effect of temperature, substrate concentration and PH on ethanol yield was studied. The maximum yield of ethanol was achieved at temperature of 32.718℃, substrate concentration of 125g/l, and PH of 4 with maximum ethanol yield of 42.598% at this condition