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METHODS FOR INCREASING THE PRODUCTION OF ETHANOL FROM MICROBIAL FERMENTATION

United States Patent Application

20080213848
A1
View the Complete Application at the US Patent & Trademark Office
A stable continuous method for producing ethanol from the anaerobic bacterial fermentation of a gaseous substrate containing at least one reducing gas involves culturing in 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 of 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.
Gaddy, James L. (Fayetteville, AR), Arora, Dinesh K. (Fayetteville, AR), Ko, Ching-Whan (Fayetteville, AR), Phillips, John Randall (Fayetteville, AR), Basu, Rahul (Bethlehem, PA), Wikstrom, Carl V. (Benton, AR), Clausen, Edgar C. (Fayetteville, AR)
Emmaus Foundation, Inc. (Fayetteville AR)
11/ 876,312
October 22, 2007
[0002] This invention was made with government support under Grant Nos. DE-FC04-94AL98770, 85X-TA046V, 85X-SX613V awarded by the US Department of Energy, and under Grant No. 96-MRC-1-0077 awarded by the US Department of Agriculture. The government has certain rights in the invention.