Fig. 6

Optimization of GABA production by E. coli BL21(DE3)/SsGAD from L-Glu. a Effect of the cell concentration on GABA yield. The reactions were performed with 7 M L-Glu in water at 37 °C for 2 h and with a cell density of OD₆₀₀ 20; b Effect of the PLP concentration on GABA yield. The reaction was carried out at 37 °C for 2 h with 4 M L-Glu and a cell density of OD₆₀₀ 20 in water. c Time course analysis of GABA formation in single-batch reactions with 1 M, 2 M, 3 M, and 4 M L-Glu. The concentrations of cells and PLP were OD₆₀₀ 20 and 0.2 mM, respectively; d Batch reactions with reused E. coli BL21(DE3)/SsGAD with a cell density of OD₆₀₀ 20