Production efficacy of γ-aminobutyric acid (GABA) from Lactic Acid Bacteria (LAB)
using low-cost medium substrates

γ-aminobutyric acid (GABA) is a significant inhibitory neurotransmitter that plays an indispensable role in immunomodulation, cardiovascular function, the alleviation of psychotic

disorders, hypertension, etc. Given its significant therapeutic potential, there is growing interest in microbial GABA production. However, cost-effective, high-yield production methods, particularly using vegetable-based growth media, remain limited. This study has focused on the cost-effective, high yielding GABA-producing Lactic Acid Bacteria (LAB) using High-Performance Liquid Chromatography (HPLC), focusing on ten probiotic LAB. In addition to the coventional growth of LAB on MRS media, MRS broth was supplemented with varying concentrations of MSG salt (Monosodium Glutamate) at 0.5%, 1%, 1.5%, and 2%, for a comparative analysis of high-yielding GABA production. Moreover, different concentrations of MSG were also evaluated on a vegetable-based edible growth medium to explore possible alternative cost-effective methods of GABA extraction. The cultures were incubated at 37°C for 48 hours and analysis of GABA production was quantified in both media by HPLC. The vegetable-based edible medium was evaluated against MRS broth for GABA production efficiency. Results showed that MRS broth with 1% MSG significantly enhanced GABA yield compared to conventional MRS media. Two different strains of Lactiplantibacillus plantarum showed GABA production in a noticeable rate, with 169.97 mcg/mL and 246 mcg/mL, respectively. Furthermore, some results for GABA production showed promising efficacy using edible substrate media with 32.44 mcg/mL and 27.64 mcg/mL at 250ppm and 750ppm, respectively, for a strain of Lactiplantibacillus plantarum, which is a promising contribution to the cost-effective method of GABA extraction. Also, commercial yoghurt samples were collected and analyzed for GABA quantification, which resulted in a poor concentration of trace GABA. In conclusion, this study demonstrates the superior GABA producing potential of probiotic LAB compared to low-cost medium substrates and highlights the potential application of these strains for developing GABA-enriched functional food.