Fig. 3

Ethanol and electricity co-production performances of knockout strains of genes associated with NAD(P)H consumption in the TCA cycle. a Ethanol production yields of 5D, Δmae, Δmdh1, Δmdh2, Δmdh3, Δidp1, Δidp2, Δidp3, Δoye2, and Δoye3 knockout strains using glucose when run in the MFC for 24 h with an open circuit. b Ethanol production yields 5D and nine knockout strains using glucose when run in the MFC for 24 h in an external circuit. c Open-circuit potential of the original 5D strain and nine knockout strains running in the MFC for 24 h. d External-circuit potential of the original 5D strain and nine knockout strains operating in the MFC for 24 h with a 1000 Ω resistor connected externally in the MFC. e Linear scan voltammetry curves of the original 5D strain and nine knockout strains in the MFC at a sweep speed of 2 mV/s. f Power density curves of the original 5D strain and nine knockout strains in the MFC at a sweep speed of 2 mV/s. The MFC was run at 35 °C and 500 rpm. Values are shown as the mean ± s.d. (n = 3)