Monday, May 2, 2011
Grand Ballroom C-D, 2nd fl (Sheraton Seattle)
In an environmentally benign process biomass can be used as source of fuel ethanol. This is produced by enzymatic hydrolysis of the cellulose and hemicelluloses to monomeric sugars, which are then fermented to ethanol. The biomass is usually pretreated under high temperature and pressure in aqueous solution to improve enzyme accessibility and enhance the hydrolysis. The residual hydrolysis resistance is believed to be driven by the adsorption of enzymes to lignin and/or the formation of a physical barrier by lignin in respect to accessibility to cellulose.
In the present work the influence of the adsorption of enzymes to lignin is examined in model systems containing filter paper. Lignin from pretreated materials was isolated by extensive enzymatic hydrolysis, which removes practically all carbohydrates producing a cellolytic lignin (CL). Four CL samples were produced from wheat straw and corn stover, where two different pretreatment processes were applied. CL samples do adsorb enzymes but the impact of this on initial hydrolysis yield of filter paper test systems is small. Presently little attention is given to the state and chemical composition of CL which is discussed in relation to enzyme adsorption and overall hydrolysis yield.