A Metabolic Pathway Allowing the Production of Putrescine from Agmatine in Food Lactic Acid Bacteria

LUCAS, PM; BLANCATO, VS; MAGNI, C; LOLKEMA, J; LONVAUD-FUNEL, A

Bologna, Italia

Simposio; Food Micro2006; 2006

International Committee on Food Microbiology and Hygiene (ICFMH); International Union of Microbiological Societies (IUMS); University of Bologna; Società Italiana di Microbiologia Agroalimentare e Ambientale (SIMTREA)

Lactic acid bacteria present in fermented food and beverages can produce biogenic amines such as histamine, tyramine or putrescine from amino acids present in the medium. These transformations enable the bacteria to resist the acid stress and to produce metabolic energy. Putrescine is generally the most abundant biogenic amine in wine. It was recently demonstrated that it could be produced from ornithine by an ornithine decarboxylase. Ornithine itself is produced from arginine, one of the most abundant amino acids in wine, via the arginine deiminase pathway. We have previously sequenced the genes involved in the production of tyramine in a Lactobacillus brevis strain isolated from wine. During this study, we have detected the 5'-extremity of another gene coding for an enzyme related with those of the arginine deiminase pathway. Here, we continued the sequencing of Lb. brevis in the area located downstream of this gene. The complete sequence revealed a six-genes cluster that is also present in the genome sequences of Pediococcus pentosaceus, Listeria monocytogenes and Lactobacillus sakei. Two of the six enzymes were cloned, overexpressed and purified. Their enzymatic activity indicates that they are an agmatine deiminase and a membrane transporter catalysing the agmatine/putrescine exchange.  These results confirm that the six enzymes form an agmatine deiminase pathway allowing the production of putrescine from agmatine. PCR analyses suggest that this pathway is largely widespread in lactic bacteria of wine and that it is often associated with the tyramine-producing pathway.