CONSTRUCTION AND CHARACTERIZATION OF CELLULOLYTIC YEASTS.

The successful construction of cellulolytic yeast strains could lead to improvements in the traditional processes, such as brewing, distilling and wine making, and to more versatile utilization of cellulose for energy production and in novel yeast based applications. Five different cellulolytic yeast strains were constructed in this study. The genes coding for the cellobiohydrolases CBHI and CBHII, and the endoglucanases EGI and EGIII of the filamentous fungus Trichoderma reesei, as well as the beta -glucosidase gene of Aspergillus niger, were expressed in the yeast S. cerevisiae. All recombinant yeast strains were able to hydrolyse natural cellulosic substrates present in yeast culture medium showing different cellulolytic capabilities.