Trichoderma reesei: genetic approaches to improving strain efficiency

For cost-effective, economically competitive production of bioethanol from cellulosic plant matter improvements in the production of enzymes to depolymerize the plant biomass are necessary. The fungus Trichoderma reesei is a prolific producer of cellulases and hemicellulases, and intensive research efforts are ongoing to further increase strain efficiency by maximizing enzyme production levels and optimizing the produced enzyme cocktail. With the genome sequencing of T. reesei QM6a cellulase research has entered a new era. Whole-genome comparisons of hyperproducing strains provide new insights into the mechanisms relevant for cellulase gene expression. The recent discovery that this fungus is also susceptible to sexual crossing opens new possibilities for strain improvement by combining beneficial properties or crossing out deleterious ones. In this review we outline new strategies, tools and recent developments based on genomic and proteomic approaches that are now available to gain better insights into the cellulolytic enzyme machinery of T. reesei.