In this paper, the production ofγ-aminobutyric acid (GABA) by Streptococcussalivarius subsp, thermophilus Y-2 was investigated systemically respect to the screeningand identification of glutamate decarboxylase (GAD) [EC 4.1.1.15] producing strain,purification and characterization of novel GAD, culture conditions for GAD production,biotransformation conditions for GABA production using cells, preparation of GABA bysubmerged fermentation and the purification of GABA. Three methods, i.e., the pHindicato...