Fig. 6

Analysis of l-proline-overproducing strains. a Flask cultivation of different C. glutamicum strains. b Simulation of the impact of increased ACONTa(b) flux on cellular metabolism for robustness analysis was investigated with increasing relative ACONTa(b) fluxes (between 1.0 and 5.0). X-axis relative ACONTa(b) flux (the ratio of the test ACONTa(b) flux to the native ACONTa(b) flux). Relative ACONTa(b) flux = 1.0 served as the control (or native GPD flux). Y-axis relative flux of the pathways (the ratio of the test flux to the native flux). Yellow represents no change, red represents upregulation, and blue represents downregulation of the flux. Descriptions of abbreviated reaction names are provided in Additional file 3. c Relative transcript expression of related genes of the analyzed C. glutamicum strains in the exponential growth phase in glucose. Significant differences in the data were determined using Student’s t test (*P < 0.05, **P < 0.01). The data were derived from experiments performed at least three times, and the error bars represent the standard deviations