Fig. 3
Effects of different inducers on GFP production. Growth curves of E. coli BL21 (DE3) cells overexpressing GFP upon induction with IPTG (A), lactose (B), and CWP (C), at 25 °C for 48 h. Cell density (black line, OD600), specific fluorescence (red line) and concentrations of glycerol (blue line) and lactose (dotted line) are plotted as a function of growth time. The vertical dashed line indicates the addition of the inducer, the error bars indicate the standard deviation of three independent measurements. D–F GFP production by a single cell was determined by flow cytometry from whole cells taken times after induction with IPTG (D), lactose (E), and CWP (F). The mean values of three (A–C) or four (D–F) independent measurements are represented with error bars indicating standard deviations. Statistical analyses were performed using unpaired two-tailed Student’s t-test, n.s.: not significant p > 0.05, *p < 0.05, **p < 0.01, ***p < 0.001