Biodegradation of oxytetracycline and electricity generation in microbial fuel cell with in situ dual graphene modified bioelectrode.

A three-step method to prepare dual graphene modified bioelectrode (D-GM-BE) in microbial fuel cell (MFC) in previous studies. This study explored the biodegradation of oxytetracycline (OTC) and electricity generation in O-D-GM-BE MFC. The OTC removal efficiency of graphene modified biocathode and bioanode (O-GM-BC, O-GM-BA) was 95.0% and 91.8% in eight days. The maximum power density generated by O-D-GM-BE MFC was 86.6 ± 5.1 mW m-2, which was 2.1 times of that in OTC control bioelectrode (O-C-BE) MFC. The Rct of O-GM-BA and O-GM-BC were decreased significantly by 78.3% and 76.3%. OTC was biodegraded to monocyclic benzene compounds by bacteria. O-GM-BA was affected strongly by OTC, and Salmonella and Trabulsiella were accounted for 83.0%, while typical exoelectrogens (Geobacter) were still enriched after the maturity of biofilm. In O-GM-BC, bacteria related with OTC biodegradation (Comamonas, Ensifer, Sphingopyxis, Pseudomonas, Dechloromonas, etc.) were enriched, which contributed to the high removal efficiency of OTC.