Phenol degradation in bio-electrochemical cells

A bio-electrochemical cell (BEC) was constructed as a typical two-chamber microbial fuel cell (MFC), except that it was operated under external voltage instead of constant resistance as in an MFC. The anode chamber contained a pure culture of Cupriavidus basilensis grown in a medium containing phenol as the sole carbon source. Operating the BEC under an external voltage of 125mV led to an increase in bacterial cell growth to 0.53OD_{600 nm}, while the control (open circuit potential) BEC reached only 0.24OD. The total dry weight of the bacterial cells in the poised potential BEC was 48% higher than in the control BEC. The peak current generated in the poised potential BEC was 478mAm^-2. The level of residual phenol in the control potential BEC was between 47% and 78% higher than that in the poised potential BEC. The rate of phenol degradation as a function of 0.1OD was about 0.36mg phenoll^-1h^-1. Cyclic voltammetry examination at the end of the experiment demonstrated an oxidation peak above-0.06V. In conclusion, operating the BEC at 125mV enabled growth of a pure culture of C.basilensis, current formation, and phenol degradation even in an oxygen-limited environment.