Methods for increasing the production of ethanol from microbial fermentation

Patent · 23 October 2007

OSTI ID:941118

Gaddy, James L ^[1]; Arora, Dinesh K ^[1]; Ko, Ching-Whan ^[1]; Phillips, John Randall ^[1]; Basu, Rahul ^[2]; Wikstrom, Carl V ^[1]; Clausen, Edgar C ^[1]

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1. Fayetteville, AR
2. Bethlehem, PA

A stable continuous method for producing ethanol from the anaerobic bacterial fermentation of a gaseous substrate containing at least one reducing gas involves culturing a fermentation bioreactor anaerobic, acetogenic bacteria in a liquid nutrient medium; supplying the gaseous substrate to the bioreactor; and manipulating the bacteria in the bioreactor by reducing the redox potential, or increasing the NAD(P)H TO NAD(P) ratio, in the fermentation broth after the bacteria achieves a steady state and stable cell concentration in the bioreactor. The free acetic acid concentration in the bioreactor is maintained at less than 5 g/L free acid. This method allows ethanol to be produced in the fermentation broth in the bioreactor at a productivity greater than 10 g/L per day. Both ethanol and acetate are produced in a ratio of ethanol to acetate ranging from 1:1 to 20:1.

• Research Organization: BIOENGINEERING RESOURCES, INC.
• Sponsoring Organization: United States Department of Energy
• DOE Contract Number: FC04-94AL98770
• Assignee: Emmaus Foundation, Inc. (Fayetteville, AK)
• Patent Number(s): 7,285,402
• Application Number: 10/311,655
• OSTI ID: 941118
• Country of Publication: United States
• Language: English

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