Engineered an accessory enzymatic system of cellulase for simultaneous saccharification and co-fermentation

The enhanced hydrolysis of xylan-type hemicellulose is important to maximize ethanol production yield and substrate utilization rate in lignocellulose-based simultaneous saccharification and co-fermentation system. In this study, we conduct d-integration CRISPR Cas9 to achieve multicopy chromosomal integration with high efficiency of reductase-xylitol dehydrogenase pathway in Saccharomyces cerevisiae . Subsequently, we devise a CBP-enabling S. cerevisiae consortium, in which every engineered yeast strain could secrete or display different assembly component to be adaptive assembled on the surface of scaffoldin-displaying yeast cell for synergistic catalysis and co-fermentation from steam-exploded Pennisetum purpureum . Despite the accumulation of xylitol, the maximum ethanol titer of genetic engineered yeast strain reached 12.88 g/l with the cellulose conversion of 91.21% and hemicellulose conversion of 55.25% under 30 ºC after 96 h with the addition of commercial cellulase. The elaborated cellulosomal organization toward genetic engineering of an industrially important microorganism presents a designed approach for advanced lignocellulolytic potential and improved capability of biofuel processing.