Process for the acid hydrolysis of carbohydrate polymers and the continuous fermentation of the sugars _obtained therefrom to provide ethanol

摘要

A carbohydrate polymer such as starch and/or cellulose is converted to ethanol by a process in which an aqueous slurry of the carbohydrate polymer acid hydrolyzed to provide a sterile fermentable sugar solution is thereafter continuously converted by fermentation to dilute aqueous ethanol ("beer") in a series of agitated fermentations vessels which contain progressively more ethanol and less fermentable sugar employing at least two strains of yeast for the fermentation, one of which provides a high rate of ethanol production in a fermentation medium containing a relatively low concentration of ethanol and a relatively high concentration of fermentable sugar and the other of which provides a high rate of ethanol production in a fermentation medium containing a relatively high concentration of ethanol and a relatively low concentration of fermentable sugar.