Composite additives enhance high-solids enzymatic hydrolysis of CuCl₂-catalyzed organosolv pretreated sugarcane bagasse

To boost the enzymatic hydrolysis of CuCl₂-catalyzed organosolv pretreated sugarcane bagasse, the single and composite additives were introduced to decrease the negative influence of residual lignin. By adding the optimal loadings of composite additives (e.g., 30 mg Tween 80, 40 mg tea saponin, 40 mg bovine serum albumin (BSA), and 0.8 mg xylanase based on per g substrate), the highest glucose yield reached 96.5% after hydrolysis for 48 h. Furthermore, the composite additives were introduced to high-solids enzymatic hydrolysis, and the partial supplement of the pretreated substrate and enzyme increased the highest glucose concentration to 194.3 g/L (including 10.8 g/L oligomer glucose), accounting for 88.8% of total fermentable sugars (218.9 g/L). This fed-batch mode along with the composite additives provided a beneficial approach for high-solids enzymatic hydrolysis, the high proportion of glucose was also convenient for commercial bioethanol production using industrial bacterial strains.