Monday, May 5, 2008 - 3:30 PM
6-04

Developing high performance enzymes for biomass saccharification by de novo cocktail design and DirectEvolution™ enzyme optimization

Alexander Varvak, John Poland, Mark Dycaico, Chris Lyon, Chad Scharlach, Shaun Healey, David Weiner, Kevin Gray, and Justin Stege. Verenium Corporation, 4955 Directors Place, San Diego, CA 92121

Effective enzymatic saccharification of pretreated biomass requires simultaneous synergistic action of multiple exo- and endo-acting cellulases and, in some cases, hemicellulase enzymes. Significant improvement in enzyme performance is needed in order to survive harsh process conditions and lower the cost contribution of enzymes to biomass saccharification applications.  Verenium has leveraged its large collection of cellulase and hemicellulase enzymes to develop custom-made de novo cocktails optimized for specific biomass feedstocks, pre-treatment, and other process conditions. Verenium’s DirectEvolution™ technology is uniquely suited to further improve cellulolytic performance and process compatibility of individual enzymes. Reduction of enzyme dose while maintaining the efficiency and extent of biomass conversion is a key property that can be improved by DirectEvolution™.  In addition, improvements of specific enzyme properties can make enzymes compatible with harsh process conditions, such as high temperature, extreme pH, or high product concentrations. Novel assays have been developed that permit screening of cellulases in the presence of accessory enzymes on desized and pretreated lignocellulosic and cellulosic substrates under relevant process conditions in a high-throughput manner. Using application-derived biomass as substrate for evolution screening allows rapid improvement of the most commercially relevant properties. In this manner, we have successfully evolved a GH family 11 xylanase for superior thermotolerance by applying GSSM™ technology to identify best individual thermostabilizing mutations, followed by combinatorial blending of single mutants to produce an improved variant with Tm 25 ºC higher than the parent enzyme.


Web Page: www.verenium.com