Production of gamma-aminobutyric acid from red kidney bean and barley grain fermentation by Lactobacillus brevis TISTR 860

The study was to investigate gamma-aminobutyric acid (GABA) production from red kidney bean and barley grain by Lactobacillus brevis TISTR 860 (LB860) and L. brevis TISTR 868 (LB868), strains isolated from traditional Thai vegetables. The results showed that LB860 produced a higher GABA yield per monosodium glutamate (MSG) content in MRS medium, comparing with LB868. GABA production by LB860 using MSG and red kidney bean as the substrate was 1.2-fold higher than that from barley grain. Various concentrations of glucose as the carbon source and peptone as the nitrogen source were assessed. After the optimization of the culture medium composition, the maximal GABA yield of 44.47 +/- 0.02 mM was produced from MRS medium containing MSG 2%, non-germinated red kidney bean milk 10%, glucose 2% and peptone 1% (w/v) by L. brevis TISTR 860 after incubation at 28 +/- 2 degrees C for 12 days in a shaking flask. In conclusion, red kidney bean was more efficient than barley grain as a substrate for GABA production by Lactobacillus brevis TISTR 860. Optimization of the culture medium enhanced GABA production. These findings may be applied in the development of cosmetic and health products.