(374t) Ethanol Production From Glucose and Xylose Sugars Produced Via a Biochemical Route From Ionic Liquid Pretreated Lignocellulosic Biomass

Lignocellulosic biomass is primarily composed of three macromolecular components; cellulose, hemicellulose and lignin. These components are chemically bonded by non-covalent forces and by covalent cross linkages. Enzymes can be used to break down these macromolecules and hydrolyze the polysaccharides into simple sugars. Yeast and other micro-organisms can ferment these sugars to ethanol fuel. The enzymatic hydrolyzability is hindered by the recalcitrance of biomass largely due to the high crystallinity of cellulose. The crystallinity of cellulose is mitigated by ionic liquid (IL) pretreatment. IL pretreatment results in amorphous cellulose while retaining significant amounts of hemicellulose and lignin, making the lignocellulosic biomass amenable to hydrolysis and fermentation. In the present study, structural changes of cellulose dissolution in IL and recrystallization have been examined by X-ray diffraction and Raman spectroscopy studies. IL pretreated hydrolyzates can be fermented to ethanol by priming Pichia stipitis with xylose rich streams followed by cellulase enzyme supplementation. Strategies in sequential or hybrid saccharification and fermentation of IL pretreated substrates can mitigate end product inhibition in saccharification and reduce required enzyme loading.