Bioethanol production from wheat straw

Abstract
New pretreatment methods were developed for separating hemicellulose, cellulose, and lignin from biomass of wheat straw for their efficient use in the thermo-chemical conversion of each component. One method is basically a two-step process. Biomass treated in hot water at 180 °C was extracted in a flowing stream of water/ethanol mixture under 40 bar at 210 °C. Through the hot water treatment, hemicellulose in biomass was successfully recovered as saccharides, leaving lignin and cellulose as a solid. Through the sequential extraction by the water/ethanol solvent, lignin was depolymerized into the water/ ethanol-soluble compounds and the residual cellulose was partly dehydrated. Through the enzymatic hydrolysis of cellulose and fermentation of recovered glucose bioethanol was produced. The proposed methods were expected to be new routes for converting low-grade plant resources into valuable chemicals such as bioethanol and also by-products such as hemicellulose and lignin.