Project Number: 5325-41000-041-00
Project Type: Appropriated

Start Date: May 01, 2003
End Date: Dec 31, 2004

Objective:
Develop, by use of directed molecular evolution (DME), a set of improved specific enzymes to convert (1) starch-rich substrates directly into fermentable sugars and (2) cellulose and hemicellulose to glucose and specialty chemicals. Apply these enzymes to improve grain-to-ethanol (biofuels) fermentation conversion, as well as to create conversion processses that are effective at lower temperatures, thus minimizing the huge energy input required during typical ethanol production. Develop, by use of directed molecular evolution techniques, alpha-amylase and glucoamylase enzymes that can function optimally under the same reaction conditions. Alpha-amylase will be engineered for cold hydrolysis. Glucoamylase will be engineered to operate at a higher pH. This research will be coordinated with other research contributing to the ARS Bioenergy and Energy Alternatives National Program (NP 307).

Approach:
Create and test novel biocatalysts for the ability to (1) convert cold ungelantinized starch to glucose (i.e. alpha-amylases) and (2) convert agriculturally derived lignocellulosics to glucose and other platforms (i.e. cellulases). These enzymes will reduce the need for pre-processing starch and cellulose via harsh thermnal or chemical treatments during grain-to-ethanol fermenntation. New enzymes are created through Directed Molecular Evolution (DME), in which a large library of yeast variants are created by varying the gene encoding for enzyme production. This library is screened for particular activity, such as the ability to convert cold wheat starch into glucose, or the ability to specifically modify cellulose. After screening, selected mutants are used to generate a new library of active strains. This cycle is repeated until the desired biocatalyst is obtained. DME will also be applied to psychrophillic organisms. Target substrates will be wheat starch, wheat fiber (middlings), corn starch, agriculturally derived fibers, and other grain-derived biopolymers. FY02 Program Increase. Add 2 SYs. FY03 Program Increase $178,830. Replacing 5325-4100-035-00D (06/03).