Graduate Student Michigan State University East Lansing, Michigan
Body of Abstract: Plant cell walls, as the majority of lignocellulosic biomass, have been a promising renewable resource of biomaterials and biofuel. The biopolymer networks of cell walls consist of rigid scaffolds of cellulose microfibrils embedded in hemicellulose and lignin in the secondary cell walls. Solution NMR and chromatography require isolation, chemical modification, and solubilization procedures, which compromise the physical properties and chemical structures of biomacromolecules. Multidimensional solid-state NMR (ssNMR) spectroscopy has emerged as a useful technique for investigating whole plant cells in their native environment. First, the method was used to investigate the nanoscale assembly of lignocellulosic components in the stems of grass (maize), hardwood (eucalyptus and poplar), and softwood (spruce). Using intact plant cells, we obtained information on the polymorphic structure, dynamical and hydration profile, and physical packing of polysaccharides and lignin. Lignin was found to preferentially bind the non-flat domains of xylan in most plants, but also bind cellulose and the flat-ribbon domain of xylan in woody stems. Secondly, our ongoing study used ssNMR to monitor the lignification process in Arabidopsis. The results showed the lignification process is related to the heights of the stems and the positions of the cut on the stem (basal, middle, and apical). These studies will guide the development of more digestible crops and cost-effective conversion technology for biofuel production and the development of plant-based biomaterials.