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U.S. Department of Energy
Office of Scientific and Technical Information

By-product inhibition effects on ethanolic fermentation by Saccharomyces cerevisiae

Conference ·
OSTI ID:5749973

Inhibition by secondary fermentation products may limit the ultimate productivity of new glucose to ethanol fermentation processes. New processes are under development whereby ethanol is selectively removed from the fermenting broth to eliminate ethanol inhibition effects. These processes can concentrate minor secondary products to the point where they become toxic to the yeast. Vacuum fermentation selectively concentrates nonvolatile products in the fermentation broth. Membrane fermentation systems may concentrate large molecules which are sterically blocked from membrane transport. Extractive fermentation systems, employing nonpolar solvents may concentrate small organic acids. By-product production rates and inhibition levels in continuous fermentation with Saccharomyces cerevisiae have been determined for acetaldehyde; glycerol; formic, lactic and acetic acids; 1-propanol; 2-methyl-l-butanol; and 2,3,-butanediol; to assess the potential effects of these by-products on new fermentation processes. Mechanisms are proposed for the various inhibition effects observed.

Research Organization:
Lawrence Berkeley Lab., CA (USA)
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
5749973
Report Number(s):
LBL-13343; CONF-810813-15; ON: DE82003714
Country of Publication:
United States
Language:
English