Process for the hydrolysis of starch and the continuous fermentation of the sugars obtained therefrom to provide ethanol

US4243750A · kind A · utility

Assignee

• National Distillers and Chemical Corporation · US

Inventors

• Werner C. Muller · Harsewinkel, DE
• Franklyn D. Miller · Cincinnati, US

Key dates

• Filing date: May 29, 1979
• Grant date: Jan 6, 1981
• Expiry date: May 29, 1999

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S435/94
• WIPO field: Biotechnology
• WIPO sector: Chemistry

Abstract

Starch is converted to ethanol by a process in which an aqueous starch slurry is hydrolyzed in sequential liquefication and saccharification steps to provide sterile saccharified starch solution containing from about 60 to about 80 weight percent of fermentable sugar based on the weight of the original starch present and the fermentable sugar is thereafter continuously converted by fermentation to dilute aqueous ethanol ("beer") in a series of agitated fermentation 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.