Isolation, properties and behaviour of tyramine-producing lactic acid bacteria from wine

Wines containing high levels of biogenic amines were investigated for the p resence of tyramine-producing strains. Two different Lactobacillus brevis ( IOEB 9809 and IOEB 9901) able to produce the amine were isolated. None of t he isolated strains identified as Oenococcus oeni formed tyramine. In addit ion, other Lact. brevis and Lact. hilgardii strains from our collection (IO EB) and the American Type Culture Collection (ATCC) were strong tyramine pr oducers. Lactobacillus brevis IOEB 9809 and Lact. hilgardii IOEB 9649 were found to produce tyramine and phenylethylamine simultaneously. The conditio ns that can influence tyramine formation in wine were evaluated for three s trains of Lact. brevis (IOEB 9809 and IOEB 9901) and Lact. hilgardii (IOEB 9649). Tyrosine was the major factor affecting tyramine formation and was e nhanced by the presence of sugars, mainly glucose. Tyrosine decarboxylase ( TDC) activity greatly depended on the presence of the precursor, which sugg ested that tyrosine induced the TDC system. These results indicate that Lac tobacillus could be the lactic acid bacteria responsible for tyramine produ ction in wine.