Effects of surfactants on ethanol production from rice straw by simultaneous saccharification and fermentation

The effects of biosurfactant rhamnolipid and chemical surfactant Tween 80 on ethanol production from waste rice straw by simultaneous saccharification and fermentation (SSF) were investigated. The results showed that ethanol yield was increased to different extents by the two surfactants at the optimal condition. The maximum enhancements were obtained at the reaction time of 72 hours, at which time ethanol yields were 84.8% and 91.7% with presence of 1CMC (Critical Micelle Concentration) of rhamnolipid and Tween 80, and the ethanol yields were 12.2% and 21.3% higher than the control, respectively. The experiment proved that rhamnolipid and Tween 80 could improve the complex system of SSF. Ethanol concentration was also increased remarkably with two surfactants. The stimulatory effects on ethanol yield of Tween 80 were superior to that of rhamnolipid. Tween 80 did not inhibit cell growth in fermentation processes and probably improved the utilization of reducing sugar by yeast. For its complexity of reactive system, many influencing factors, more research is needed to investigate effects of surfactants on yeast.