Isolation and evaluation of exoelectrogenic bacteria in a baffled air-cathode microbial fuel cell

Facultative tube methods were adopted for isolation from biofilm in two compartments of a baffled air-cathode microbial fuel cell (BAFMFC). The separated strains were then putted into a sterile cubic MFC individually under the same condition in order to evaluate its electrogenic characteristic. Electrochemical impedance spectrometer (EIS) was employed for the internal resistance testing. It can be found that ohmic internal resistance was around 25Ω, indicating the cell performance determined only by activity of the strain. Nineteen strains were obtained, seven of which had voltages over 200 mV under 1000Ω. The strain (A2), owned the highest electrogenic activity in compartment A, has a voltage of 328 mV with the maximum power density 165.1 mW/m². The maximum power density of 214.4 mW/m² was produced by the isolate B1 (the best exoelectrogenesis in compartment B), while the maximal voltage of 241 mV was achieved. Identification of fatty acids reveals that A2 belongs to Enterobacteriaceae, and B1 belongs to the genus Bacillus.