Construction of a minicellulosome-producing consolidated bioprocessing reaction system for simultaneous saccharification and co-fermentation from Pennisetum purpereum

Abstract 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, a mincellulosome attaching with hemicellulose-degrading enzymes on this xylose-utilizing recombinant yeast strain is developed for synergistic catalysis and co-fermentation from steam-exploded Pennisetum purpereum. Despite the accumulation of xylitol, the maximum ethanol titer of genetic engineered yeast strain reached 4.77 g/l with the cellulose conversion of 97.02% and hemicelluose conversion of 67.45% 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.