Wednesday, May 2, 2012: 8:30 AM
Napoleon Ballroom A and B, 3rd fl (Sheraton New Orleans)
Fundamental insights into the macromolecular structure and properties of biomass provided by microscopy techniques in tandem with new analytical methods will enable strategies for the production of advanced fuels and chemicals from biomass. Here we introduce and demonstrate the application of methodology to discern the 3D nanoscale architecture of cellulose microfibrils within thermochemically pretreated biomass by fitting parametric space curves to subvolumes of transmission electron tomographic datasets. The resulting mathematical approximation of the nanoscale geometry is combined with the crystal structure of cellulose 1β to propose atomistic models that reflect the macromolecular architecture of the microfibrils in the sample volume. The curvature exhibited by the microfibril models may be calculated directly from the fitted parametric equations, and we further propose a method to infer the twist of the individual fibrils from the macromolecular geometry by orienting the structures such that the majority of the bending of the fibril is accommodated its most flexible dimension. These atomistic models of cellulose microfibrils are the first to incorporate 3D macromolecular geometry obtained directly from electron microscopy, and this methodology will remain fluid and current by the revising the physical and mathematical criteria by which the molecular models are constructed as the knowledgebase is expanded by the scientific community.