Effect of nutrient supplements on molasses fermentation by salt preconditioned cells of Saccharomyces cerevisiae

Abstract

Molasses, the major by-product of sugarcane processing industry, is an efficient and economical source for ethanol production. In the present work, the effect of yeast extract, tween-80 and ergosterol on molasses fermentation was studied using salt preconditioned Saccharomyces cerevisiae MTCC 11815 cells. Design expert 10.0 software under RSM plan was used to optimize the nutrient concentrations and four responses viz. residual brix, ethanol, glycerol and trehalose produced were recorded. Thus, with optimized nutrient concentrations, the salt preconditioned cells showed significantly better ethanol production (11.45%, v/v) as compared to controls viz. preconditioned un-supplemented cells (9.92%, v/v) and unconditioned cells (8.13%, v/v). Further, the molasses fermentation was validated at 10L scale and 11.67% (v/v) of ethanol was produced with 86.83% fermentation efficiency with 0.523% (w/v), 0.251% (v/v) and 3.8mg/100ml of yeast extract, tween-80 and ergosterol supplementation, respectively.