Screening and Identification of Gaba-Producing Bacteria from Lemea, A Traditional Fermented Food

Introduction: Gamma-aminobutyric acid (GABA) is a functional bioactive compound known for its health-promoting properties and is commonly found in fermented foods. Although numerous studies have investigated GABA production from various fermentation substrates, Lemea, a traditional fermented food from Indonesia, remains an underexplored source of GABA-producing bacteria. Objective: This study aimed to quantify GABA production by bacterial isolates obtained from Lemea and to identify the most potent GABA-producing strain through molecular characterization. Methods: Six bacterial isolates previously screened for GABA production were rejuvenated and cultured in de Man, Rogosa, and Sharpe Broth (MRSB) supplemented with glutamic acid for 36 hours. GABA concentrations in the culture supernatants were quantified using an ultra-performance liquid chromatography-photodiode array (UPLC-PDA) method (18-5-167/MU/SMM-SIG), with analyses performed in duplicate. The isolate exhibiting the highest GABA production was identified by 16S rRNA gene sequencing.Results: The results showed that GABA production among the isolates ranged from 40.09 ± 1.17 mg/L to 113.03 ± 0.15 mg/L. The highest GABA-producing isolate was molecularly identified as Staphylococcus epidermidis, exhibiting a 100% sequence similarity coefficient. Conclusion: These findings demonstrate that Lemea is a promising source of GABA-producing bacteria. The identification of Staphylococcus epidermidis as a high GABA-producing strain suggests its potential application in the development of functional fermented food products.