Monday, April 29, 2013
Exhibit Hall
Most cellulolytic enzymes used in the biomass to biofuels or bioproducts industry are derived from the filamentous fungus Trichoderma reesei. It is almost certain that this organism would be the source for such hydrolytic enzymes for this fledgling industry for the foreseeable future. In order to ensure that genetic improvements made in these enzymes are functional in T. reesei, the engineered genes need to be expressed in T. reesei and those gene products evaluated for their biochemical and enzymatic properties. We have developed expression hosts and corresponding vectors for two T. reesei strains, QM6a, a “wild-type” strain and Rut C-30, in which expression of cellulases is mostly constitutive. We have replaced the cbh1 genes in QM6a and in Rut C-30 with A. nidulans amdS and E. coli hygromycin B phosphotransferase genes, respectively, and developed expression vectors for inserting heterologous genes into these strains. These systems are being used to 1) produce chimeric cellulases that would combine the desired characteristics of enzymes from different organisms, 2) produce improved forms of cellulases by rational design or random mutagenesis, 3) examine efficacy and mode of action of native and heterologous enzymes produced in T. reesei, and 4) develop T. reesei as a direct microbial platform to convert biomass to biofuels and bioproducts.