Promoting cellulase and hemicellulase production from Trichoderma orientalis EU7-22 by overexpression of transcription factors Xyr1 and Ace3.

The construction of hyper-production strains of cellulase is the prerequisite for the production of biofuels or biochemicals. Trichoderma orientalis EU7-22 with complete cellulase system shows the potential for cellulase production in industrial scale. To improve the cellulase production, two crucial transcription activators Xyr1 and Ace3 were constitutively overexpressed in EU7-22 strain. Cellulase, xylanase and protein secretion were significantly improved in the recombinant strain dxyA-8 under inducing culture, which were 2.34, 0.68 and 1.06 folds higher than those of EU7-22, respectively. Moreover, the FPase and CMCase activities were up to 2.55 IU/mL and 90.38 IU/mL with glucose as carbon source, which were 2.12 and 1.95 folds higher than those of EU7-22 under inducing condition, respectively. Reducing sugar released from pretreated spartina that hydrolyzed by crude enzyme from dxyA-8 had achieved 24% improvement. Therefore, overexpression of these transcription factors effectively promotes the production of cellulase and hemicellulase of Trichoderma orientalis EU7-22.