Simultaneous saccharification and fermentation of cellulosic biomass to produce ethanol

摘要

A process for simultaneous saccharification and fermentation of a cellulosic solids fraction extracted from a lingocellulosic feedstock. The process comprises: (i) separating an extracted lingocellulosic feedstock into a cellulosic solid fraction and a liquids fraction; (ii) processing the liquids fraction to remove extracted lignins to produce a de-lignified liquids fraction; (iii) reducing the viscosity of the cellulosic solids fraction by intermixing it with the de-lignified liquids fraction; (iv) intermixing the reduced-viscosity cellulosic solids fraction with (a) a fermentative microbial culture consisting of Saccharomyces spp. and (b) a cellulosic biomass degrading enzyme preparation selected from the group consisting of cellulases, hemicellulases, beta-glucosidase, beta-xylosidase, alpha-amylase, beta-amylases and glycanases; (v) commingling the mixture of (iv) to provide a reaction mixture comprising ethanol; and (vi) separating ethanol from the reaction mixture. Alternatively, the viscosity of the solids fraction may be reduced by intermixing with a liquid carbohydrate stream comprising one or more monosaccharides. The microbial culture can be Saccharomyces cerevisiae strain Y-1528.