Effect of Rice Bran as a Nitrogen and Carbohydrate Source on Fed-Batch Simultaneous Saccharification and Fermentation for the Production of Bioethanol from Rice Straw

Abstract

Rice bran contains useful components such as starch, fiber, and protein. In this study, we investigated the use of rice bran as an inexpensive nutrient supplement for the growth of yeast in simultaneous saccharification and fermentation (SSF) for bioethanol production from rice straw. We found that rice bran was as effective a nutrient as corn steep, which is the yeast nutrient typically used in SSF. The addition of rice bran during SSF also increased the sugar concentration, thus improving the initial growth rate of the yeast cells and rapidly creating a stable SSF condition as well as increasing the final ethanol concentration. In the lab-scale experiment, the final ethanol concentration reached 69.3 g/L, and the ethanol yield was 79 %. Thus, we achieved highly efficient utilization of rice bran in SSF of rice straw in the lab-scale experiments, and these findings were verified in pilot-scale SSF experiments.