Understanding the Molecular Basis for Cellulose Recalcitrance with Atomistic Simulation

Friday, November 12, 2010: 9:10 AM
255 A Room (Salt Palace Convention Center)
Gregg T. Beckham1, James F. Matthews2, William S. Adney2, Michael E. Himmel2 and Michael F. Crowley2, (1)National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, (2)Biosciences Center, National Renewable Energy Laboratory, Golden, CO

Cellulose-degrading organisms in the biosphere have evolved a complex cocktail of enzymes for overcoming biomass recalcitrance. Most enzyme cocktails contain both processive and non-processive cellulases, which are able to de-crystallize single cellulose strands and hydrolyze the glycosidic linkages along a cellulose chain. A ubiquitous step that both processive and non-processive cellulases must accomplish is cellulose de-crystallization, for which there is an inherent thermodynamic penalty. Here, we measure the thermodynamic cost for cellulose de-crystallization as a function of cellulose morphology and polymorph at the atomic scale with molecular simulation. Our results indicate how enzymes may have evolved to degrade biomass in the biosphere at the molecular-level and suggest directions for increasing the enzymatic accessibility for cellulose digestion in biofuels applications.

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