Effect of initial cell, yeast extract and sugar concentrations on ethanol production from molasses by thermotolerant yeast Saccharomyces cerevisiae RMU Y-10

摘要

Effect of fermentation factors, i.e., initial cell (5-15%), yeast extract (3-9 g/l) and initial sugar concentrations (120-220 g/l) on ethanol production from molasses using thermotolerant yeast Saccharomyces cerevisiae RMU Y-10 were investigated. An L9 (34) orthogonal array design was used to optimize the fermentation factors, and the fermentation experiment was carried out at 37°C using batch mode. Results showed that initial sugar concentration had a major effect on ethanol production, followed by yeast extract and initial cell concentrations, respectively. Optimum initial cell, yeast extract and initial sugar concentrations for ethanol production by thermotolerant yeast S. cerevisiae RMU Y-10 were 15% (v/v), 3 and 120 g/l. Highest ethanol concentration (56.62 g/l), ethanol yield (0.50) and ethanol productivity (1.57 g/l/h) were achieved under optimum fermentation conditions. Results also showed that ethanol concentrations obtained under the optimum conditions were 25.82, 94.04 and 64.55% greater than those in YM medium (control 1), molasses only (control 2) and molasses supplemented with YM medium (control 3) experiments, respectively with fermentation time reduced to 36 h.