23-Butanediol synthesis from glucose supplies NADH for elimination of toxic acetate produced during overflow metabolism

摘要

a Reactions related to ethanol production and 2,3-BD biosynthesis in E. cloacae SDM. AdhE, bifunctional acetaldehyde/ethanol dehydrogenase; BudB, α-acetolactate synthase; BudA, α-acetolactate decarboxylase; BudC, 2,3-butanediol dehydrogenase; AC, acetoin; 2,3-BD, 2,3-butanediol. b Growth of E. cloacae SDM using glucose as carbon source. c Growth of E. cloacae SDM (ΔadhE) using glucose as carbon source. d Growth of E. cloacae SDM (ΔbudABC) using glucose as carbon source. e Consumption of exogenous added 13C acetate by E. cloacae SDM and its derivatives. f Production of 13C ethanol by E. cloacae SDM and its derivatives. g Yield of 13C ethanol from 13C acetate by E. cloacae SDM and its derivatives. 13C sodium acetate at a concentration about 10 mM was added into the culture system of E. cloacae SDM, E. cloacae SDM (ΔadhE), and E. cloacae SDM (ΔbudABC) at 2 h. After 4 h of culture, the concentrations of 13C ethanol and 13C acetate were assayed. Experiments were carried out under aerobic conditions. Data shown are means ± SD (n = 3 independent experiments). ***P < 0.001 in two-tailed Student’s t-test.