Friendly Fermenters or Toxic Triggers? Metabolic mapping and phylogenetic analysis of biogenic amine-producing and degrading lactic acid bacteria

The excessive generation and accumulation of biogenic amines (BAs) in protein-rich diets have been highlighted as a major health concern due to their potential toxicity. As a result, the tendency has shifted toward using lactic acid bacteria as a safe starting culture in foods that can degrade or transform BA into a nontoxic product. However, it has been found that certain LAB strains use their own decarboxylase enzymes to convert the amino acid precursor into BA. The diversity of LAB strains with decarboxylase activity, a critical factor in the conversion of amino acids into BA, has been investigated. Furthermore, the diversity of LAB strains that break down BA into nontoxic compounds using diverse enzymes has been thoroughly investigated. The mapping of enzymes specific to the genus and species levels of the LAB strains engaged in the entire BA metabolism, from amino acid synthesis to breakdown, is also revealed. The enzymes involved in the generation and degradation of BAs from different LAB strains are closely examined in terms of evolutionary relatedness. This study has important practical implications for managing BA levels in food items by carefully selecting and employing single or mixed cultures of LAB strains as starter cultures.