GABA (γ-aminobutyric acid) is the major inhibitory neurotransmitter in mammalian nervous system and has number of physiological functions. The glutamate decarboxylase encoded by the gadB gene converts L-glutamate to GABA. Taking into account the beneficial properties of GABA for health improvement, we have analyzed the presence of the gadB gene in Lactobacillus spp. natural isolates from LMM laboratory collection by in silico analysis; conserved CoreF/CoreR primers and a degenerate primer GAD typing methods were used as well. The results revealed that 50% of tested Lactobacillus spp. isolates harbour gadB. Among them two Lactobacillus brevis strains (BGZLS10-17 and BGZLS30-2) and Lactobacillus plantarum BGAN8 showed the best GABA production based on thin layer chromatography (TLC). Additionally, concentration of GABA was quantified by UltraPerformance Liquid Chromatography (UPLC) analysis. Production of GABA from monosodium glutamate (MSG) is by far the most potent system to resist acidic conditions in bacteria. Thus, the pH of GABA-producing strains in the presence of MSG was monitored for 48 hours. The results obtained suggest that GABA could be involved in pH regulation of lactobacilli. Finally, the probiotic potential of three selected lactobacilli was evaluated by various in vitro probiotic tests (antimicrobial activity assays, survival under simulated gastrointestinal conditions, adhesion and pathogens’ exclusion abilities). In conclusion, in vitro tests indicated that L. brevis BGZLS10-17 and BGZLS30-2 as well as L. plantarum BGAN8 are good probiotic candidates that could be eventually used in formulation of functional starter cultures for production of innovative foods.

Trabajo presentado en el 13th Congress of Nutrition (CONU), celebrado en Belgrado (Serbia) del 26 al 28 de octubre de 2016

Peer reviewed