VIEW ARTICLE    DOI: 10.1094/ASBCJ-53-0049

Control of Vicinal Diketone Production by Brewer's Yeast. I. Effects of ILV5 and ILV3 Gene Amplification on Vicinal Diketone Production and ILV Enzyme Activity. K. D. Villa and S. Lee, Coors Brewing Company, B.C. 600, Golden, CO; E. Goossens, A. Debourg, and C. A. Masschelein, Vrije Universiteit, Brussel, CERIA Service de Brasserie, Ave. E. Gryzon, 1, 1070 Brussels, Belgium. J. Am. Soc. Brew. Chem. 53(2):49-53, 1995. Accepted September 11, 1994.

The amount of vicinal diketone (VDK) precursors produced during the brewery fermentation process was minimized by increasing the flux through the isoleucine-valine (ILV) biosynthetic pathway in brewer's yeast. Plasmid amplification of the gene products of ILV5, ILV3, or tandem ILV5+ILV3 in brewer's yeast resulted in VDK decreases of 70, 40, and 60%, respectively, when compared to that of normal brewer's yeast. No other flavor or attenuation profile differences were observed. Overall, ILV5 gene amplification was a very effective strategy for decreasing total VDK production. Keywords: Diacetyl, Isoleucine-Valine (ILV), Vicinal diketone (VDK)