(86b) One Step Cellulosic Ethanol Production

A whole-cell biocatalyst system was developed in our research to directly produce ethanol from amorphous cellulose (Phosphoric acid swollen cellulose, PASC) in a single step. This whole cell biocatalyst was constructed with LY01, which is one of the most developed ethanologenic Escherichia coli strains, as a host cell. The cellulase genes, celCCA, celCCE and beta-glucosidase, were prepared from the mesophilic strain Clostridium cellulolyticum. To enhance the stability and activity of the cellulosic enzymes, these enzymes were co-displayed with the anchor protein PgsA on the surface of the host cell. For inducing the synergism of enzymes, this recombinant cellulolytic microorganism co-expressed endoglucanase, cellobiohydrolase, and beta-glucosidase simultaneously. The saccharification product, monosaccharides, can be uptaken immediately by the host cell and produce ethanol so that the inhibition of the catalytic activity of enzymes can be efficiently prohibited. In this research, we also applied the whole-cell biocatalyst system in bioethanol production process with the lignocellulosic biomass as a substrate.