Improve Hydrolysis Rate by Displaying Multi-Complex of Cellulolytic Enzymes and Produce Ethanol In One-Step Process

Simultaneous saccharification and fermentation (SSF) steps have been performed in order to reduce the cost of bioethanol production process. A whole-cell biocatalyst system was developed previously in our system to directly produce ethanol from cellulose in a single step. Three types of cellulases, which were endoglucanase, cellobiohydroalse and beta-glucosidase originated from Clostridium cellulolyticum were expressed on the cell surface. Genetically engineered Escherichia coli LY01 (Dr. LO Ingram, University of Florida) was used as a host microorganism. Our previous system was shown that the hydrolysis rate was 83 % and the theoretical ethanol yield was 87 % from amorphous cellulose. Attempts to improve the saccharification efficiency, we construct multi-complex of cellulases on the surface of microorganism.