Fed-batch mode optimization of SSF for cellulosic ethanol production from steam-exploded corn stover

Abstract

To achieve a desired ethanol concentration and maximize substrate concentration, the fed-batch simultaneous saccharification and fermentation (SSF) process was performed on steam-exploded corn stover using the yeast strain Saccharomyces cerevisiae Y5. The fed-batch SSF experiments were conducted with feed loading and scheduled feed time conditions that were optimized with response surface methodology (RSM). The overall ethanol yield (based on the raw material cellulose content) in 48 h was as high as 64.0%, which was achieved with a final substrate loading of 26%(w/w), enzyme loading of 7 FPU/g cellulose, and dry yeast loading weight of 2.0 g/L. No additional yeast cells or enzymes were added during solid substrate fermentation.