Fig. 4

Bio-electrochemical characterization of the extracellular electron transfer (EET) and electricity output capability of the four engineered S. oneidensis strains (namely XE, GE, XS, and GS) with xylose as the sole carbon source. a Voltage output of the four engineered S. oneidensis strains (XE, GE, XS, and GS) in the semi-batch xylose-fed multiple operational cycles of MFCs. Upon vanishing of electricity output and depletion of xylose at each MFC cycle, 18 mM xylose was added to maintain the multiple MFC operation cycles. b Cyclic voltammetry (CV) at the scan rate of 1 mV/s. c Polarization curves and power density output curves of the MFCs inoculated with the four recombinant S. oneidensis strains, respectively. The error bars were calculated from triplicate experiments