Pretreatment and Fractionation of Wheat Straw for Production of Fuel Ethanol and Value-added Co-products in a Biorefinery

摘要

An integrated process has been developed for a wheat straw biorefinery. In this process, wheat straw was pretreated by soaking in aqueous ammonia (SAA), which removed lignin but preserved most of the carbohydrate fractions. The pretreated material was hydrolyzed with a commercial hemicellulase to provide a solution rich in xylose and low in glucose. This solution then was used for production of value-added products. In this investigation xylitol and astaxanthin were used to demonstrate the fermentability of the xylose-rich hydrolysate. The cellulose-enriched residue obtained after the enzymatic hydrolysis of the pretreated straw was used for ethanol production in a fed-batch SSF process. In this process, a commercial cellulase was used for hydrolysis of the glucan in the residue and the yeast S. cerevisiae, which is the most efficient commercially suitable ethanol-producing organism, was used for ethanol production. Final ethanol concentration above 50 g/l was obtained.