Isolation and Characterization of β-Phenylethylamine-Producing Lactic Acid Bacteria from Dairy Products

β-phenylethylamine (PEA) is a neuroactive trace amine synthesized by the enzymatic decarboxylation of phenylalanine. PEA is involved in the improvement of mood and attention. Functional foods enriched in this compound could, therefore, be of interest to the food industry. PEA is produced by microbial activity in certain foods, but usually only in small amounts. The search for PEA-producing microorganisms with good technological properties is thus a pre-requisite if such functional foods are to be produced. This work reports the isolation of thirty-three PEA-producing bacterial strains from samples of different dairy products. They belong to the genus Enterococcus, and the species Levilactobacillus brevis. Identified strains of Enterococcus durans were then selected for technological characterization. Some of them showed properties of interest. In this species, PEA was determined to be produced via the action of tyrosine decarboxylase, encoded by the gene tdcA. This implies that, apart from PEA, a concomitant production of tyramine, a toxic biogenic amine, was observed.