Badal C. Saha and Rodney J. Bothast

Fermentation Biochemistry Research Unit, National Center
for Agricultural Utilization Research, Agricultural Research Service,
U. S. Department of Agriculture, 1815 North University Street,
Peoria, TL 61604

Advances in enzymes and lignocellulosic biomass processing are necessary to lower the cost of fuels and chemicals production from biomass. Recent developments in lignocellulosic biomass conversion enzymology and process technology are reviewed. Current problems of these multi-enzymes based complex processes, economic assessment, regulatory issues, strategies for development of improved enzymes and processes, and directions of future research are discussed. Results of our endeavor to develop novel enzymes for biomass conversion are presented.

Currently, more than one billion gallons of ethanol are produced annually in the United States, with approximately 95% derived from fermentation of com starch (7). Enzymes play an important part in the conversion of com starch to glucose that is then fermented to ethanol by yeast. In fact, application of amylases in starch conversion is a great example of the successful use of enzymes in biotechnology. With increased attention to clean air and oxygenates for fuels, opportunities exist for rapid expansion of the fuel ethanol industry. Various lignocellulosic biomass such as agricultural residues, wood, municipal solid wastes and wastes from pulp and paper industry have potential to serve as low cost and abundant feedstocks for production of fuel ethanol or chemicals. Right now, the use of lignocellulosic biomass to produce fuel ethanol represents significant technical and economic challenges, and its success depends largely on the development of highly efficient and cost-effective biocatalysts for conversion of pretreated biomass to fermentable sugars. In this article, we describe briefly current knowledge on the application of enzymes in various lignocellulosic biomass conversion.