Electrochemical wiring of the Gram-positive bacterium Enterococcus faecalis with osmium redox polymer modified electrodes

•The second Gram-positive bacterium Enterococcus faecalis was “wired” to an electrode with an osmium redox polymer.•The bacterium is able to transfer electrons from its respiratory chain to an electrode.•d-glucose of different concentrations was used as the electron donor.

The Gram-positive bacterium Enterococcus faecalis was investigated to test its ability to electrochemically communicate with electrodes. E. faecalis cells were successfully “wired” to gold electrodes through [Os(2,2′-bipyridine)2-poly(N-vinylimidazole)10Cl]2 +/+ redox polymer. Maximum current density achieved in response to 10 mM d-glucose was 18 ± 1 μA cm− 2. Control experiments without redox polymer showed no current response. This demonstrates the efficiency of the osmium-based mediator in electron transfer between the cells having a thick cell wall and the electrode. The findings have significant importance in microbial electrochemistry for further understanding of microbe-electrode interactions.