Isolation and Production of γ-Aminobutyric Acid (GABA) from Lactic Acid Bacteria from Seredele, a Balinese Fermented Soybean

γ-Aminobutyric acid (GABA) is a major inhibitory neurotransmitter with beneficial effects on human health. Therefore, this study aimed to isolate lactic acid bacteria (LAB) from seredele, a Balinese fermented soybean, with GABA-producing potential. 16S rRNA sequencing was used to assess bacterial communities in seredele, with Providencia, Enterococcus, Vagococcus, and Bacillus identified as the predominant genera. The results showed that strains S11B and S211K produced the highest GABA levels and were identified as Limosilactobacillus fermentum and Enterococcus faecium, respectively. E. faecium S211K had maximum GABA production at 24 hours of cultivation, while L. fermentum S11B had maximal production at 48 hours. Both strains remained viable for up to 120 hours of cultivation. In conclusion, seredele serves as a source for isolating GABA-producing LAB, emphasizing the significance of local LAB with functional properties.