Title: EVOLUTIONARY ENZYME DESIGN FOR IMPROVED BIOREFINING OF CROPS AND RESIDUES Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 25, 2006
Publication Date: August 16, 2006
Citation: Wong, D., Lee, C.C., Wagschal, K.C., Smith, M.R., Robertson, G.H., Orts, W.J. 2006. Evolutionary enzyme design for improved biorefining of crops and residues. Technical Program (abstract). P8. Technical Abstract: The biorefining of grains (starch) and crop residues (fibers) to fermentable substrates for the production of biofuels and high-value chemicals represents an important renewable source of energy. The enzyme group at the Western Regional Research Center has focused on the development of enzymes and enzyme systems for cold hydrolysis of starch granules and for the complete breakdown of hemicellulosic materials. We have made use of combinatorial chemistry and molecular biology techniques to discover, express, and evolve these enzymes for targeted structures and functions. We screen DNA libraries to isolate or discover genes by sequence and functional selections, cloning them into E. coli and yeast for expression; we then purify and characterize the enzymes for specific biochemical properties. Selected clones are targeted for directed evolution studies for improvement, and further evaluated using combinatorial approaches. The following groups of enzymes are currently at various stages of development: α-amylase, glucoamylase, endo-β1,4-xylanase, β-xylosidase, α-L-arabinofuranosidase, acetylxylan esterase, and feruloyl esterase. Enzyme systems consisting of various combinations of individual enzymes are being tested and evaluated.