6-06: Real-time imaging of plant cell wall structure at nanometer scale, with respect to cellulase accessibility and degradation kinetics

Cost-effective production of lignocellulosic biofuels is contingent upon deeper understanding of the structure and chemistry of plant cell walls, as well as of the molecular basis of the conversion processes such as chemical pretreatment and enzymatic saccharification. Label-free and real-time imaging approaches, such as coherent Raman scattering and single molecule tracking, are employed for the first time to investigate plant cell wall structure at nanometer scale, spatial distribution of chemical constituents of the cell wall, and kinetics of degradation by fungal “free” cellulase and bacterial cellulosome systems in situ.  Specific objectives of these studies are to determine (1) structures and spatial arrangements of microfibrils in plant cell walls, and how they affect accessibility to cellulases and ultimate digestibility, (2) differences in the relationships of cellulose and lignin in different types of plant cell walls, and the ways in which these differences affect the efficiency of pretreatment and enzyme hydrolysis, and (3) the locations at which  cellulases bind to the cell wall, in relation to the manner in which individual microfibrils are hydrolyzed. Preliminary (published and unpublished) results will be presented and discussed.