Cellulase Production by a New Mutant Trichoderma afroharzianum MEA-12 and its Efficient Saccharification of Biomass

Considering the inhibitory effect of catabolites in most cellulase-producing strains, this study obtained a mutant of Trichoderma afroharzianum (T. afroharzianum) by exposures to N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), Ethyl Methanesulfonate (EMS), Atmospheric and Room Temperature Plasma (ARTP) and adaptive laboratory evolution (ALE) with high sugar stress. The T. afroharzianum mutant MEA-12 produced 0.60, 5.47, 0.31 and 2.17 IU/mL FPase, CMCase, pNPCase and pNPGase, respectively. These levels were 4.33, 6.37, 4.92 and 4.15 times higher than those of the parental strain, respectively. MEA-12 can tolerate the inhibition of glucose (up to 20 mM) without affecting enzyme production under inducing conditions. Interestingly, crude enzyme from MEA-12 showed high enzymatic hydrolysis efficiency against bamboo pulp, when combined with cellulase from Trichoderma reesei (T. reesei) Rut-C30. In addition, the factors that improved cellulase production by MEA-12 were clarified.