Fig. 4

Performances of multiple knockout strains for ethanol and electricity co-production. a Ethanol production yields of 5D, ΔdΔm, ΔdΔm1, ΔdΔm3, ΔdΔi1, ΔdΔi2, ΔdΔi3, ΔdΔo2, and ΔdΔo3 knockout strains using glucose when run in the MFC for 24 h in an open circuit. b Ethanol production yields of 5D and eight knockout strains using glucose when run in the MFC for 24 h in an external circuit. c Open-circuit potentials of the original 5D strain and eight knockout strains running in the MFC for 24 h. d External-circuit potentials of the original 5D strain and eight knockout strains operating in the MFC for 24 h with 1000 Ω resistors connected externally in the MFC. e Linear scan voltammetry curves of the original 5D strain and eight knockout strains in the MFC at a sweep speed of 2 mV/s. f Power density curves of the original 5D strain and eight knockout strains in the MFC at a sweep speed of 2 mV/s. The MFC was operated at 35 °C and 500 rpm. Values are shown as the mean ± s.d. (n = 3)