Efficient Isolation and Characterization of a Cellulase Hyperproducing Mutant Strain of Trichoderma reesei

A cellulase hyperproducing mutant strain, JNDY-13, was obtained using the ARTP mutation system and with RUT-C30 as the parent strain. Whole-genome sequencing of JNDY-13 confirmed that 105 of the 653 SNPs were point mutations, 336 mutations were deletions and 165 were insertions. Moreover, 99 mutations were insertions and duplications. Among all the mutations, the one that occurred in the galactokinase gene might be related to the production of cellulases in JNDY-13. Moreover, the up-regulation of cellulase and hemicellulase genes in JNDY-13 might contribute to higher cellulases production. Under optimal conditions, the highest cellulase activity by batch fermentation reached 4.35 U/ml, and the highest activity of fed-batch fermentation achieved was 5.40 U/ml.