Abstract
Purpose: γ-Aminobutyric acid (GABA) is recognised as a potential metabolic bioactive food ingredient with increasing evidence of its effects on the gut-brain axis and systemic metabolic health. Different lactic acid bacteria are capable of producing GABA, particularly strains of Lactobacillus brevis. In this study, we characterized a Lb. brevis isolated from traditional alpine cheese (Lb. brevis DSM 32386) for its ability to accumulate high levels of GABA in the culture medium and for other important probiotic phenotypic traits. Methods: In vitro analysis were used to study the Lb. brevis DSM 32386 probiotic traits and the gene expression involved in GABA production Result: Lactobacillus brevis DSM 32386 converted monosodium glutamate to GABA more efficiently than the type strain Lb. brevis DSM 20054, resulting in more than 200% of GABA produced. This ability seemed to be related to the higher transcriptional activation of the gene encoding for the glutamate (gad) decarboxylase antiporter (gadC) and regulator (gadR). Lactobacillus brevis DSM 32386 performed well in vitro under the stress conditions mimicking the gastro-intestinal tract, being resistant to acid pH (pH 2.5) and growing in simulated pancreatic fluid and 0.3% ox-bile. Conclusion: These preliminary studies indicate that Lb. brevis DSM 32386 holds promise as a starter for GABA-rich dairy fermented foods and possibly a promising next-generation probiotic microorganism in the context of the gut (microbiota):brain axis.