Fig. 2: Mechanism of 2,3-BD biosynthesis supports acetate elimination. | Cell Discovery

Fig. 2: Mechanism of 2,3-BD biosynthesis supports acetate elimination.

From: 2,3-Butanediol synthesis from glucose supplies NADH for elimination of toxic acetate produced during overflow metabolism

Fig. 2

a Copy numbers of budA in E. cloacae SDM during growth in glucose and glucose supplemented with 40 mM sodium acetate at mid-log stage (n = 5). b Copy numbers of adhE in E. cloacae SDM during growth in glucose and glucose supplemented with 40 mM sodium acetate at mid-log stage (n = 5). c Relative β-galactosidase activity in E. cloacae SDM, E. cloacae SDM (ΔbudR) and E. cloacae SDM (Δfnr) containing pME6522-PbudA or pME6522-PadhE at mid-log stage. The β-galactosidase activity in E. cloacae SDM is assumed to be 1. d Ratio of NADH/NAD+ in E. cloacae SDM, E. cloacae SDM (ΔbudABC), and E. cloacae SDM (ΔadhE) at mid-log phase. e Ratio of NADH/NAD+ in E. cloacae SDM, E. cloacae SDM-pETPc-nox, and E. cloacae SDM (ΔbudC). f Yield of 13C ethanol from 13C acetate in E. cloacae SDM, E. cloacae SDM-pETPc-nox and E. cloacae SDM (ΔbudC). 13C sodium acetate at a concentration of about 10 mM was added into the culture system of these strains at 2 h. After 4 h of culture, the concentrations of 13C ethanol and 13C acetate were assayed. g Concentration of AC, 2,3-BD, ethanol, and the theoretical concentration of ethanol in E. cloacae SDM and E. cloacae SDM (ΔbudC) when cultured under anaerobic conditions. Experiments in a−f were carried out under aerobic conditions. Data shown are means ± SD. (n = 3 independent experiments). *P < 0.05 in two-tailed Student’s t-test; **P < 0.01 in two-tailed Student’s t-test; ns, no significant difference (P ≥ 0.05 in two-tailed Student’s t-test).

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