Structural Studies of Enzymatic Hydrolysis of Cellulose by Neutron Scattering and Reflectivity

Abstract

Improving the efficiency of enzymatic hydrolysis of cellulose is a key technological hurdle in reducing the cost of producing ethanol from lignocellulosic material. Typically, enzymatic hydrolysis proceeds to only a limited extent, high solution-to-solids ratios are required, and the rate of enzymatic hydrolysis typically decreases with time. A range of mechanisms have been proposed to explain these phenomena including product inhibition, denaturation of enzymes, nonproductive binding, and many others. We are studying the interaction of enzymes with cellulose to help unravel these mechanisms. Our studies include UV absorption and circular dichroism of enzymes in solution, small angle neutron and X-ray scattering (SANS, SAXS) of cellulose during hydrolysis, and neutron reflectivity (NR) of enzymes interacting with model cellulose surfaces. Insight from these studies should aid the development of more efficient enzyme systems and pretreatments.