Sunday, April 29, 2007

Development of a chimeric glycosyl hydrolase for conversion of biomass for production of biofuels and bioproducts

Kurt Wagschal1, Charles C. Lee1, George H. Robertson1, Dominic W.S. Wong1, and Ling Yuan2. (1) USDA Western Regional Research Center, 800 Buchanan Street, Albany, CA 94710, (2) Department of Plant and Soil Sciences, KTRDC, University of Kentucky, Cooper & University Drives, Lexington, KY 40546

The complete hydrolysis of arabinoxylans requires a suite of glycosyl hydrolase (GH) enzymes that includes endo-xylanases and β-xylosidases which act on the xylan main chain, as well as enzymes which remove various side chains and break cross links between xylan and other plant cell-wall polymers.  Producing the requisite enzymes as chimeras is an attractive approach since it lowers the number of  proteins that must be expressed, either by an organism dedicated to enzyme production or in-planta. Also, this strategy affords the opportunity to investigate the synergetic potential of physically coupled enzymes. A fusion protein between a GH family 39 β-xylosidase and a GH family 51 arabinofuranosidase was generated, and the separate enzyme activities as well as combined activities characterized. This dual-function xylosidase/arabinofuranosidase fusion will be used as a single enzyme in directed evolution experiments for further improvement of both enzyme activities.