Genome shuffling of Trichoderma viride for enhanced cellulase production

Abstract

Genome shuffling is an efficient approach for the rapid engineering of microbial strains with desirable industrial phenotypes. In this study, we used genome shuffling in an attempt to improve the cellulase production of the wild-type strain Trichoderma viride TL-124. The initial mutant populations were generated by ultraviolet (UV) irradiation, low-energy ion beam implantation and atmospheric pressure non-equilibrium discharge plasma (APNEDP). The mutants were subjected to recursive protoplast fusion. The cellulase activities of shuffled strains were assayed after solid-state fermentation using wheat straw, an economical raw material, as substrate. The shuffled strain T. viride F161, which was selected from among about 2,000 shuffled strains after two rounds of genome shuffling, exhibited a total cellulase activity of 4.17 U g-1 dry weight, which was 1.97-fold higher that of wild-type strain T. viride TL-124 (2.12 U g-1 dry weight). Analysis by random amplification of polymorphic DNA revealed genetic differences between the shuffled strains and the wild-type strain.