Fig. 5

Time course metabolomics of in the central metabolic pathway (a) and amino acid metabolism (b). Relative abundances of metabolic intermediates in recombinant C. glutamicum strain KT01 during 3-amino-4-hydroxybenzoic acid (3,4-AHBA) production under controlled dissolved oxygen (DO) levels at 0, 2.6, and 5.3 ppm using the DO-stat program in synthetic CGX II medium containing d-glucose as the sole carbon source are shown. The X-axis indicates cultivation time (h). For the profiling experiment, strain KT01 was grown under aerobic conditions until the late log phase in brain heart infusion medium, and the culture was then inoculated to an initial OD600 of 0.2 into CGX II medium containing d-glucose as the sole carbon source (40 g/L). The cells were harvested at 24, 48, and 72 h of cultivation and subsequently subjected to metabolome analysis. Data are presented as average ± standard deviation calculated from the results of triplicate individual experiments. N.D. not determined below the detection limit