Understanding Thermal Pretreatment of Lignocellulosic Biomass
Plants contain substantial amounts of cellulose, hemicellulose, and lignins. Much research is being devoted to developing ways to convert these materials (commonly called ‘lignocellulose’) into fuels. The first step, breaking down the biomass into these three constituents, is particularly difficult to study due to the complexity of ways in which they are entangled in biomass. A new approach has been developed that combines x-ray and neutron beam studies with advanced computational modeling to visualize the breakdown of biomass in wood chips from aspen trees. The research, led by scientists at Oak Ridge National Laboratory, studied the wood chips as they were exposed to a variety of treatments, including steam explosion pretreatment, dilute acid pretreatment, and ammonia fiber expansion. The experiments visualized the structural changes in the biomass during the processing, showing for example how porosity of the cell walls and extent of hydration of the different biomass components changes as treatments proceed. The key mechanisms responsible for structural changes are the dehydration of cellulose fibers and lignin-hemicellulose phase separation. These fundamental insights will guide the development of more efficient pretreatments. The research was featured on the January 2014 cover of Green Chemistry.
Langan, P., L. Petridis, H. M. O’Neill, S. Venkatesh Pingali, M. Foston, Y. Nishiyama, R. Schulz, B. Lindner, B. L. Hanson, S. Harton, W. T. Heller, V. Urban, B. R. Evans, S. Gnanakaran, A. J. Ragauskas, J. C. Smith, and B. H. Davison. 2014. “Common Processes Drive the Thermochemical Pretreatment of Lignocellulosic Biomass,” Green Chemistry 16, 63–68. DOI:10.1039/C3GC41962B.