Optimization of culture conditions for gamma-aminobutyric acid production by newly identified <i>Pediococcus pentosaceus</i> MN12 isolated from ‘mam nem’, a fermented fish sauce

Abstract

This study was aimed to identify and optimize the culture conditions for gamma-aminobutyric acid (GABA) production by a lactic acid bacterium strain isolated from <i>mam nem</i>, a fermented fish sauce. Among the six isolates obtained from <i>mam nem</i>, the MN12 had the most potent GABA-producing capability. The strain was then identified to be <i>Pedioccocus pentosaceus</i> by employing MALDI-TOF-MS and phenylalanyl-tRNA synthase sequencing methods. The initial cell density of 5.10⁶ CFU/mL, monosodium glutamate concentration of 60 mM, initial pH of 7, temperature of 45°C and cultivation time of 72 h were found to be the optimal culture conditions for highest production of GABA, reaching 27.9 ± 0.42 mM, by this strain. The cultivation conditions for GABA production by <i>P. pentosaceus</i> MN12 have been successfully optimized, providing a foundation for the development of fermented foods enriched with GABA.