Metamorphosis of pathogen to electrigen at the electrode/electrolyte interface: Direct electron transfer of Staphylococcus aureus leading to superior electrocatalytic activity

In this paper, we report that Staphylococcus aureus isolated from the rumen fluid can display direct electron transfer on carbon felt electrodes and exhibit enhanced microbial electrocatalysis towards the oxidation of complex substrate like cellulose. The phenomena of direct electron transfer and electrocatalysis were investigated in detail by cyclic voltammentry and chronoamperometry. The electron transfer was closer to perfect reversibility with a peak separation value of only 7 mV at a scan rate of 50 mV/s. The enhanced microbial electrocatalysis towards the oxidation of cellulose revealed the potential of the microorganism for application in microbial fuel cells. The pure cultures of S. aureus produced an electrocatalytic current density of 1.4 mA/cm2 as estimated by long-term chronoamperometry for a cellulose concentration of 20 mM. To the best of our knowledge we report for the first time the use of S. aureus for bioelectricity generation with cellulose as a sole source of electron donor.