Ethanol production from corn stover hemicellulosic hydrolysate using immobilized recombinant yeast cells

Ethanol production from corn stover hemicellulosic hydrolysate was investigated using immobilized recombinant Saccharomyces cerevisiae yeast cells. Detoxification of hemicellulosic hydrolysate by roto-evaporation and lime neutralization was carried out to remove volatile fermentation inhibitors. All furfural and more than 50% acetic acid in the hydrolysate were removed, meanwhile the xylose concentration was enhanced to 71.8 g/L. The fermentability of the detoxified hydrolysate was significantly improved using immobilized cells of recombinant S. cerevisiae by Ca-alginate. An ethanol concentration of 31.1 g/L and the corresponding ethanol yield on fermentable sugars of 0.406 g/g were obtained within 72 h in batch fermentation of the detoxified hydrolysate with immobilized cells. In addition, repeated batch fermentation of immobilized recombinant S. cerevisiae cells was attempted for ethanol production for 5 batches. The concentration of ethanol in each batch maintained above 30.1 g/L with the ethanol yield on fermentable sugars over 0.393 g/g. These results demonstrate the viability and significance of ethanol production from corn stover hemicellulosic hydrolysate.