(284f) Interactions of Cellulolytic Proteins With a Non-Native, Polysaccharide Allomorph Formed During Pretreatment of Lignocellulosic Biomass

Interactions of cellulolytic proteins with a non-native, polysaccharide allomorph formed during pretreatment of lignocellulosic biomass

Shishir Chundawat^1,2,3, Leonardo Sousa^2,3, Venkatesh Balan^2,3, Bruce Dale^2,3, Brian Fox^1,3

1. Department of Biochemistry, University of Wisconsin, Madison

2. Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing

3. DOE Great Lakes Bioenergy Research Center (GLBRC)

Cellulose III is a non-native, crystalline, cellulosic allomorph produced during a novel ammonia pretreatment process developed recently at the GLBRC. This allomorph has reduced intra-sheet hydrogen bonding but increased inter-sheet hydrogen bonding between cellulose chains compared to native cellulose I. These ultra-structural modifications have been shown to increase cellulose surface hydration and are predicted to enhance cellulose chain extraction rate from the fibril surface. We have found that despite enhanced saccharification rates for cellulose III by certain cellulase mixtures, there is a significant reduction in effective cellulase affinity for the substrate. Here, we explore the interactions of various cellulolytic enzymes and their individual domains with cellulose III to gain insight into the various factors that impact crystalline cellulose deconstruction to fermentable sugars.