Genetically modified Saccharomyces cerevisiae for one-step fermentation of bioalcohol using corncob as sole carbon source

The corncob is an important biomass for bioalcohol production. However, there is a minor but complicated pretreatment process before it is used for bioalcohol fermentation. In this study, three genetically modified Saccharomyces cerevisiae Y33 strains containing endoglucanase (EG), cellobiohydrolase (CBH), and beta-glucosidase (BG) genes were constructed. A one-step fermentation process was carried out with the recombinants using corncob as the sole carbon source. In a 3-L fermentation system, the concentration of alcohol reached 2.02 g/L and the concentration of glycerine reached 0.85 g/L after 96 h. The results prove that corncob powder can be utilized effectively by genetically modified Saccharomyces cerevisiae without any chemical pretreatment. The mixed recombinant Saccharomyces cerevisiae cells show effective synergism in the one-step fermentation system. It is feasible that corncob can be used as the sole carbon source in bioalcohol production with a one-step fermentation process.