(560b) Discovery and Characterization of Cellulolytic Enzymes From the Wood Wasp Symbiont Streptomyces Sp. ActE

One of the major hurdles for producing cost effective biofuels is the enzymatic conversion of lignocellulosic biomass into fermentable sugars. The US Department of Energy has issued the challenge of discovering and designing enzymes with novel biomass-deconstruction capabilities. This study focuses on the discovery of better enzymes and accessory proteins for biomass deconstruction from a novel bacterial species. Streptomyces sp. ActE, an isolate from wood-boring wasps of the genus Sirex. Its genomic sequence has been determined and initial physiological studies suggested high cellulolytic potential. We analyzed the genome-wide gene expression of ActE grown on insoluble substrates such as cellulose, xylan, chitin and others as the sole carbon source in the culture medium, and compared these expression profiles with glucose-grown control ActE cells. The secretomes obtained from growth on different substrates were analyzed by shotgun LC-MS/MS and enzymatic assays. From the combination of the genomic, transcriptomic, and secretomic analyses, we discovered ~200 genes that have carbon source-specific regulation of gene expression or protein secretion. This work provides the first extensive systems biology characterization of the capabilities of the genus Streptomyces for wide variety of polysaccharide utilization.

This work was funded by the DOE Great Lakes Bioenergy Research Center (DOE BER Office of Science DE-FC02-07ER64494).