The combination of continuous-pulse feeding hydrolysates with soybean hulls induction during fed-batch fermentation of Trichoderma reesei b5 significantly elevated the cellulase production and its degradation ability on lignocellulosic biomass.

To date, the high cost of cellulase is still a major factor limiting industrial production of lignocellulose bioconversion. This study developed a novel strategy combining continuous-pulse feeding glucose with soybean hulls (SBH) induction to efficiently elevate cellulase production by Trichoderma reesei b5 and enhance hydrolysis performance of cellulase on lignocellulose. In this strategy, the sugar concentration in the fermentation system was strictly controlled to meet the sugar requirements of strain for enzyme production without inhibition. Using SBH instead of microcrystalline cellulose effectively enhanced cellulase secretion as well as improved the enzyme system compositions, causing the improvement of hydrolysis performance. Using this strategy, filter-paperase (FPase) activity in the fermentation broth was more than ten-folds higher than that in batch fermentation (6.0 U/mL vs. 75.9 U/mL), and achieved the highest β-glucosidase activity reported in the literature to date (905 U/mL). This study also confirmed the feasibility of using on-site produced enzymatic hydrolysates instead of glucose as feeding medium. It provides a feasible process for large-scale production of low-cost and efficient cellulase, which is of great significance for the construction of "sugar platforms" based on lignocellulose and industrialization of lignocellulosic bioconversion.