Formation of substituted tetrahydropyridines by species of Brettanomyces and Lactobacillus isolated from mousy wines

Abstract

Three species of Brettanomyces and two species of Lactobacillus capable of producing a mousy taint have been isolated and characterized from Australian wines for the first time. Growth of Brettanomyces yeast in a chemically defined medium, with and without lysine present, indicates that two previously identified compounds which cause a mousy taint, 2-acetyl-1,4,5,6-tetrahydropyridine and 2-acetyl-3,4,5,6-tetrahydropyridine, may be synthesized from lysine. Growth of a Lactobacillus in a grape juice/yeast extract medium demonstrated the formation of the two acetyltetrahydropyridines by bacteria, and also implicated ethanol in the formation of these two compounds. Substitution of ethanol with n -propanol resulted in the novel formation of the propionyl analogues of the two mousyacetyltetrahydropyridines.