NERSC Initiative for Scientific Exploration (NISE) 2010 Awards

Molecular Mechanisms of the Enzymatic Decomposition of Cellulose Microfibrils

Jhih-Wei Chu, University of California, Berkeley

Associated NERSC Project: Molecular Simulation of the Intra- and Inter-molecular Communications through Protein Matrix (m787), Principal Investigator: Jhih-Wei Chu

To develop viable technologies for the enzymatic decomposition of cellulosic materials, mechanistic knowledge of elementary steps is indispensable. To establish such knowledge, we propose to model and simulate in silico (a) the structural deformation of a cellulose microfibril by mechanical and thermophysical means, (b) the cleavage of 1,4-glycosidic bonds on the surfaces of a microfibril by cellulases, and (c) the detachment of broken glucose chains from the microfibril into solution. For (a) and (c), we will perform simulations in aqueous solutions and in solutions of selected ionic liquids (IL). In particular, we will focus on imidazolium ILs with chloride and acetate anions. The objective is to quantify the interactions between the chemical moieties of IL molecules and the microfibril and how IL molecules modulate the free-energy barriers of deconstruction. Such analyses will be conducted in aqueous solutions as well as in water/IL mixtures to develop the molecular basis for designing better pretreatment solvents, as well as develop fundamental knowledge to facilitate the conversion of biomass into biofuels.