Fig. 5

Biotransformation of E. coli to produce GABA. a Determining the suitable substrate (MSG/l-Glu) and reaction environment (buffer/water) for the conversion. b Conversion rate with different concentrations of l-Glu. The operating conditions chosen were as follows: reaction temperature, 37 °C; reaction time, 1 h; and PLP concentration, 0.02 mM. Data are shown as the mean ± standard deviation (n = 3)