Fig. 3

Growth and GABA production of L. brevis CGMCC1306 during fermentation at different constant pH values: pH 5.2 (a) or pH 6.8 (c). The relative transcription level of gad genes during fermentation with the pH maintained at different constant pH values: 5.2 (b) or 6.8 (d). The values presented are the means of three replicate cultures; error bars representing standard deviations may be obscured by symbols