Characterization of a <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis> Strain Able to Produce Tyramine and Partial Cloning of a Putative Tyrosine Decarboxylase Gene

The aim of this article was to analyze the ability of wine Lactobacillus plantarum strains to form tyramine. Preliminary identification of L. plantarum strains was performed by amplification of the recA gene. Primers pREV and PlanF, ParaF and PentF were used respectively as reverse and forward primers in the polymerase chain reaction tests as previously reported. Furthermore, the gene encoding for the tyrosine decarboxylase (TDC) was partially cloned from one strain identified as L. plantarum. The strain was further analyzed by 16S rDNA sequence and confirmed as belonging to L. plantarum species. The tyrosine decarboxylase activity was investigated and tyramine was determined by the high-performance liquid chromatography method. Moreover, a negative effect of sugars such as glucose and fructose and L-malic acid on tyrosine decarboxylase activity was observed. The results suggest that, occasionally, L. plantarum is able to produce tyramine in wine and this ability is apparently confined only to L. plantarum strains harboring the tdc gene.