(535d) Exploration of the Effect of Ionic Liquid Pretreatment Temperature On Biomass Composition, Structure, and Enzymatic Digestibility

Deconstruction of lignocellulosic biomass into simple sugars constitutes a core barrier for producing value added products from the sugar platform.  Lignocellulosic biomass is primarily comprised of cellulose (a glucose polymer), hemicellulose (a xylose polymer), and lignin.  Enzymatic hydrolysis of cellulosic and hemicellulosic portions of biomass is one of the crucial steps in biochemical conversion of terrestrial biomass into monomeric sugars.  The native cellulosic portion of biomass has a crystalline and oriented fibrillar structure in the cellulose I crystal form.  However, cellulose I can be a major impediment for enzyme-assisted hydrolysis to monomeric sugars which can be used as a feedstock for conversion to fuel or other value added chemicals.  Ionic Liquid (IL) pretreatment can disorder the crystalline cellulosic component to an amorphous material or result in structural changes in the cellulose fibers to other crystal forms, such as cellulose II with an improvement in susceptibility to hydrolysis.  In these studies, the effects of IL pretreatment temperature on various sources of lignocellulosic biomass were examined using X-ray powder and fiber diffraction, compositional analysis and comparative enzymatic hydrolysis.  Polysaccharide digestibility was related to the observed structural and compositional changes in biomass.  The improvement in hydrolysis is hypothesized to be primarily due to structural changes in the cellulose constituent.