Stepwise transform sugarcane bagasse into xylooligosaccharides and fermentable glucose by hydrothermal-xylanase-acid-cellulase hydrolysis

Hydrothermal pretreatment can effectively degrade the hemicellulosic xylan into xylooligosaccharides; however, the low degree of polymerization (DP) oligomers are dissatisfied. Considering the significance of low DP, one approach to enhance the levels of low DP xylooligosaccharides is to utilize endo-xylanase for degrading the high DP xylooligosaccharides. Therefore, a combination method of hydrothermal and post endo-xylanase hydrolysis was employed in this study to enhance XOS yields. As a result, a maximum XOS of 54.5% with low DP was achieved from sugarcane bagasse, and the ratio of (DP2+DP3)/XOS was remarkably improved. Following the preparation of XOS, an additional acidic hydrolysis using dilute sulfuric acid was performed to enhance the saccharification efficiency of cellulose, resulting in a significant increase in yield of enzymatic hydrolysis to over 90%. Overall, biomass-derived sugar products (XOS and glucose) can be co-produced for adding the value of the sugarcane bagasse by sequential hydrothermal-endo-xylanase-acid-cellulase hydrolysis.