(714d) Incremental Disassembling of Woody Biomass and Production of Biochemicals
Woody biomass is a reliable renewable source of raw materials for energy and chemicals. Woody biomass is structurally composed of cellulose, lignin, hemicelluloses and other minor components. The compositions vary from species to species. The complexity / heterogeneity of woody biomass presents challenges to conversion technologies, which is perceived as recalcitrance. Pretreatment and detoxification have been two unfavorable but widely discussed processes todate. At SUNY ESF, a strategy of incremental disassembling of woody biomass is adopted in which hemicelluloses and extractives are separated first through hot-water extraction, cellulose and lignin are next. Hot-water extraction uses water as solvent without any other added chemicals. Acetyl groups in the woody biomass dissolve into the liquor and serves as catalyst. In each step of the separation, high value applications are examined. For example, hemicelluloses are hydrolyzed and fractionated via membrane for xylo-oligomers, xylose, acetic acid, methanol, and aromatics, etc. The residual solid mass containing mostly cellulose and lignin has wide applications: fiber board, wood fuel pellet, pulp and paper, and sugars / aromatics. Incremental disassembling is emphasized for value preservation of various components. A clever integration of the processes makes the conventional pretreatment and detoxification processes obsolete. The sugar stream produced at SUNY ESF has been successfully fermented to ethanol, butanol, lactic acid, and PHA. There is no deliberate detoxification that generates waste byproducts.