10-01: Enzymatic synergy examined using an engineered complex of cellulosomal enzymes from Clostridium thermocellum

The bacterium Clostridium thermocellum produces a formidable array of enzymes to break down lignocellulosic biomass.  Many of these enzymes are organized into structures anchored to the cell surface known as cellulosomes.  Organization of cellulosomal enzymes into complexes increases their efficacy both in the cellulosome and in engineered two- and three-enzyme complexes.  We have created an assembly based on a chaperonin from the hyperthermophilic organism Sulfolobus shibatae that binds up to eighteen cellulosomal enzymes on the ends of a nine-member double ring.  We have characterized the activity of combinations of two, three or four cellulytic enzymes attached to this structure and begun to explore activity on natural biomass substrates using combinations of enzymes including those that degrade hemicellulose.  These experiments have yielded new insights into the synergy between cellulosomal enzymes that act on distinct sites on a single substrate and those that act on distinct substrates in within biomass.