New Approaches for Visualizing Biomass Degradation
Biomass recalcitrance is the resistance of inedible plant fiber materials, mainly comprised of lignin and cellulose, to enzymatic breakdown into fermentable sugars for conversion into renewable biofuels. Researchers at the DOE BioEnergy Science Center (BESC) have applied novel imaging tools to achieve a deeper understanding of the chemical and structural architectures of plant cell walls, an important step towards overcoming recalcitrance. Coherent Anti-Stokes Raman Scattering (CARS) microscopy was used to measure the vibration patterns of individual plant cell wall molecules; these patterns were then translated into high spatial resolution chemical images of lignin within the cell wall material. Key advantages of this imaging method include the ability to study plant cell walls without chemical pretreatment to remove interfering background signals from fluorescent pigments (e.g. chlorophyll), thus minimizing damage to the native structure of the cell walls, and the ability to monitor almost simultaneously different cell wall locations. CARS was able to distinguish significant differences in lignin from normal plants versus plants engineered for low-lignin content, demonstrating its potential as a promising tool to monitor increased efficiency of chemical pretreatment and enzymatic breakdown during the biomass conversion process. The research was carried out by a team of BESC scientists at the National Renewable Energy Laboratory, Oak Ridge National Laboratory and the Samuel Roberts Noble Foundation in collaboration with Harvard University.
Yining Zeng & Brian G. Saar & Marcel G. Friedrich & Fang Chen & Yu-San Liu & Richard A. Dixon & Michael E. Himmel & X. Sunney Xie & Shi-You Ding, “Imaging Lignin-Downregulated Alfalfa Using Coherent Anti-Stokes Raman Scattering Microscopy” Bioenerg. Res. DOI 10.1007/s12155-010-9079-1