Cellulase production from kraft hardwood pulp by Trichoderma reesei rut C‐30

Cellulase on‐site production can occur in a supplementary unit in a kraft paper mill to create additional revenue. In this study, the production of cellulase enzyme from kraft hardwood pulp by Trichoderma reesei Rut C‐30 was investigated in a 3 L fermenter. Experiments were conducted at three pH levels, 3.5, 4.0, and 5.0, to study their impact on T. reesei Rut C‐30 growth and cellulase production. It was found that higher pH values promoted cell proliferation but not cellulase production. The highest cellulase activity and productivity were obtained at a pH level of 3.5. The solid loading effect of the substrate was also investigated over the range of 2% to 5% (w/v) to determine the maximum levels of cellulase activity obtainable. The highest titer of 7.5 FPU mL–1 was achieved at 4% (w/v) of hardwood pulp. Cellulase production in this condition yielded 246.7 FPU/g‐glucan of hardwood pulp with a productivity of 56.8 FPU L–1h–1. The higher xylanase activity in the enzyme produced in‐house resulted in higher glucan and xylan digestibility than the commercial enzyme. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd