11-03: Comparative glycomics of plant biomass and insights into cell wall components that affect recalcitrance

Cell walls are the principal component of plant biomass. However, the cell walls from these plants have different structures and compositions and thus may require different processing during biofuel production.  Thus, a major goal of lignocellulosic bioenergy research is to obtain in-depth knowledge of cell wall structure and processing characteristics of biomass obtained from diverse energy crops.  High-throughput comparative Glycome Profiling of biomass is a powerful approach to develop such an understanding.  This technology may also be used to identify cell wall components that affect biomass recalcitrance.  Such information is required to target and modify plant genes that contribute to recalcitrance.  Here we describe comparative glycome profiling of plant biomass using enzyme-linked immunosorbent assays (ELISA) in combination with a diverse collection of cell wall glycan-directed monoclonal antibodies that can monitor most major plant polysaccharides.  Glycome profiling of biomass from 15 different grasses revealed an abundance of xylan epitopes and much lower amounts of pectic epitopes.  Much of the pectic, pectic arabinogalactan and xylan components are integrated into the wall through interactions and/or associations with lignin.  Glycome profiling of cell walls from cell wall-modified transgenic plants and of chemically/enzymatically modified and pretreated poplar and switchgrass biomass was also used to identify key wall components that affect recalcitrance. Our studies suggest that xylans have a critical role in governing recalcitrance in grasses, whereas lignin has a major role in poplar biomass recalcitrance.