Thursday, July 30, 2009 - 4:30 PM
S167

Improving the composition of microbial cellulase mixtures for increased lignocellulosic biomass hydrolysis at lower protein loadings

Matt Sweeney, Protein Chemistry, Novozymes, Inc., 1445 Drew Avenue, Davis, CA 95618

            A major barrier in the delivery of a cost-effective process for the production ethanol from lignocellulosic biomass is the quantity of enzyme required for hydrolysis of substrate to fermentable sugar.   While some strategies rely largely on reducing the cost of this enzyme component, significant gains can also be made by improving the composition of the enzyme mixture- resulting in equivalent biomass hydrolysis at decreased enzyme loadings.   Improvements in the composition of enzymes mixtures can be made both by the addition of new enzymatic activities, or by the replacement of certain enzyme classes by members of the same class with higher activities on a given substrate.   Rational screening, the addition or replacement of certain enzyme classes, is one approach to finding improved components.  Another approach is the fractionation and screening proteins produced by wild-type microbes.   Both approaches have been successfully used to identify new components which substantially improve the performance of our enzyme mixtures in lignocellulosic biomass hydrolysis.  The strengths and limitations of each approach will be discussed.