Combining sestc engineered A. niger with sestc engineered S. cerevisiae to produce rice straw ethanol via step-by-step and in situ saccharification and fermentation

The development of agricultural residue ethanol has a profound effect on the environment protection and energy supply. To increase the production efficiency of straw ethanol and reduce operation progress, the single-enzyme-system-three-cellulase gene ( sestc ) engineered Aspergillus niger and sestc engineered Saccharomyces cerevisiae were combined to produce ethanol using the pretreated rice straw as the substrate. The present results showed that both the step-by-step and in situ saccharification and fermentation can effectively produce ethanol using rice straw as the carbon substrate. The conversion rates of ethanol were 12.76 and 14.56 g per 1 kg of treated rice straw, respectively, via step-by-step and in situ processes. In situ process has higher ethanol conversion efficiency of rice straw and fewer operation processes as compared with step-by-step process. Therefore, in situ saccharification and fermentation is a more economical and effective pathway to convert rice straw into ethanol. This study provides a reference to the conversion of lignocellulosic residues into ethanol with a combination of two kinds of sestc engineered strains.