16-02: Multiscale modeling of biomass and its degradation

Challenges encountered during the conversion of biomass to ethanol are critically linked to the uncertainties of the physical properties of the feedstock. In particular, a better understanding of lignocellulose and its biodegradation will allow one to address the factors preventing an efficient fuel economy based on cellulosic biomass conversion. One of the major challenges is the intimate association of cellulose with lignin, a recalcitrant structural component of the plant cell wall. Our Quantum mechanical study has now revealed details on how lignin can be attacked and cleaved. Also, we make predictions on dissociation energies of different linkages. This provides insights into the selection and design on the types of lignin structures that could lead to optimal delignification. Another challenge is how cellulose, an assembly of polymers of glucose, can be effectively isolated and disassembled to its basic building block, glucose. The underlying stability of cellulose comes from the dense hydrogen bonding (H-bond) network constructed among the crystalline-ordered polysaccharide chains. We have performed computations both at atomistic and coarse-grained level to investigate the thermal responses of various H-bonding networks of cellulose. Here we describe the results from computations of H-bonding in cellulose I-β, the main form of cellulose found in plants. Importantly, it provides useful clues on rational procedure for the efficient degradation. Finally, we will discuss a rule-based model for enzymatic degradation cellulose that can provide a handle on optimal enzymatic coverage and maximizing synergy on enzymatic cocktails. Research done in collaboration with ORNL, USDA, UNM and GLBRC.