Fermentation of glucose with recycle of non-fermented components

摘要

A process is described for producing a fermentation product such as ethanol, in which a feedstock is formed consisting of a slurry of starch and acid combined with a recycle stream of non-fermented carbohydrate material from a fermenter. This combined feedstock at a solids content of 15 to 30% is hydrolyzed in a single continuous hydrolyzer of a high intensity type to form a hydrolyzate in fluid form containing at least 80% glucose. The hydrolyzate is fermented to form a fermentation product and the fermentation product is distilled, leaving a distillation residue containing non-fermented carbohydrate material. This distillation residue forms the recycle stream and a substantial proportion of the non-fermented material is hydrolyzed together with the starch in a single hydrolysis stage to a fermentable glucose-containing fluid.