Fig. 2

Improving glutamic acid accumulation by adjusting odhA RBS strength of ΔC110 strain. a Cell growth; b glucose consumption; c glutamic acid accumulation. Parental (with penicillin induction) indicates the penicillin-triggered glutamic acid fermentation by parental C. glutamicum S9114 strain. Penicillin induction method is described in “Methods”. ΔC110 (control) indicates the MscCG C-terminal-truncated strain; ΔC110odhARBS20, ΔC110odhARBS10 and ΔC110odhARBS0.1 indicate the ΔC110 strains with different odhA RBS strength of 20 a.u., 10 a.u. and 0.1 a.u. substituted, respectively. Glutamic acid fermentations of engineered recombinants were carried out in 3-L fermentor (3BG-4, Baoxing Biotech Co., Shanghai, China) at 32 °C, 1.4 vvm of aeration and 600 rpm. No penicillin was added for induction. Mean values were presented with error bars representing the minimum and maximum values