Tuesday, May 3, 2011
A better understanding of the physiochemical properties of bioenergy feedstock will help improve the utilization of these crops for fuels and chemicals. Accounting for roughly 20% of the composition of bioenergy-destined feedstock, hemicellulose not only presents a barrier to accessing cellulose during enzymatic hydrolysis, but also contains sugars that can be utilized for fermentation. Better understanding of the composition and characteristics of hemicellulose could help to maximize solublizing of the material while minimizing production of inhibitory byproducts during pretreatment. This work focused on characterizing alkaline-extracted hemicellulose from Panicum virgatum (switchgrass), cultivar Alamo, harvested at pre- and post-frost. The alkaline-extracted hemicellulose was analyzed for monosaccharide components, linkage positions, and static and dynamic properties. The alkaline-extracted hemicellulose was then subjected to dilute acid pretreatment for investigation into the degradation kinetics. Preliminary results reveal that the hemicellulose is predominantly an arabinoxylan with β-(1-4)-linked xylose units comprising the backbone. Dilute acid pretreatment results yielded release of monomeric xylose and arabinose, as well as degradation products such as furfural.