(76b) Effects of Enzyme Loading and β-Glucosidase On Enzymatic Hydrolysis of Switchgrass Processed by Leading Pretreatment Technologies

Pallapolu, V. R. - Presenter, Auburn University
Lee, Y. Y. - Presenter, Auburn University
Kothari, U. D. - Presenter, Auburn University
Wyman, C. E. - Presenter, University of California, Riverside
Dale, B. - Presenter, Michigan State University
Elander, R. T. - Presenter, National Renewable Energy Laboratory
Warner, R. E. - Presenter, Genencor, A Danisco Division

Switchgrass samples pretreated by CAFI team have widely different physical characteristics and chemical composition. They were used as substrates in a study of fundamental aspects of the enzymatic hydrolysis reaction. Presence of different carbohydrates in the substrate and multitude of enzyme components in cellulase enzyme system make the hydrolysis reaction extremely complex. In an effort to better understand the reaction, the effects of cellulase enzyme loading and supplementation of external β-Glucosidase were studied. For this purpose, the time course profiles of the hydrolysis reaction products were experimentally determined applying various levels of enzyme loading with and without supplementation of β-Glucosidase. The measured reaction products include glucose, xylose, cellobiose, oligomers of glucose and xylose. All of the feedstocks generated by CAFI methods as well as pure cellulosic substrates of Avicel and chemical grade xylan were used in these experiments. The results were analyzed to assess the effectiveness of each pretreatment, correlation between the yield and enzyme loading, the isolated effect of β-glucosidase, and how the composition affect the reaction pattern and the terminal yield.