EVOLUTIONARY ENZYMES AND SEPARATION PROCESSES FOR IMPROVED BIOREFINING OF CROPS AND RESIDUES
Location: Bioproduct Chemistry and Engineering Research
Title: Metagenomic gene discovery and enzyme engineering for biomass conversion
Submitted to: American Chemical Society Western Regional Meeting
Publication Type: Abstract Only
Publication Acceptance Date: July 31, 2008
Publication Date: September 23, 2008
Citation: Wong, D., Lee, C.C., Wagschal, K.C., Smith, M.R., Robertson, G.H., Orts, W.J. Metagenomic gene discovery and enzyme engineering for biomass conversion. American Chemical Society Western Regional Meeting. American Chemical Society Symposium: New Developments in Biofuels Research. Abstract 204.
Enzymes that can be harnessed for high-efficiency breakdown of agricultural crops and crop residues have become increasingly important because of their pivotal role in the conversion of these renewable biomass materials to biofuel and other high-value products. Microbial deconstruction of plant cell wall polymers employs combined and synergistic actions of a complex array of enzymes. Research at the Western Regional Research Center (WRRC) in Albany, CA, uses an approach of metagenomic gene discovery and engineering key biomass enzymes that uniquely harness the collective genomic resource ¡§locked up¡¨ in unculturable microbes. The focus is on new genes, new enzymes, and new mechanisms to break down the complex interlinkages among cellulose, hemicellulose, pectin, and lignin, and to achieve improved rates and extent of degradation. WRRC possesses more than four dozen new genes mostly for hemicellulases and pectinases. These include endo-xylanases, ƒÒ-xylosidases, ƒÑ-L-arabinofuranosidases, acetylxylan esterases, feruloyl esterases, ƒÑ-glucuronidases, arabinanases, xyloglucanases, and rhamnogalacturonanases. More than half of the genes have been cloned and expressed in E. coli, and particular enzymes purified, characterized, evaluated, and further targeted for improvement by directed evolution. Enzyme systems consisting of various enzyme combinations are further integrated into yeast for hydrolysis and fermentation in consolidated bioprocessing.