Ferric-sulfuric co-enriched culture for enhanced bioelectricity generation performance coupled with efficient anaerobic phenol degradation ability

Microbial fuel cell (MFC) has been intensively investigated for the degradation of organic pollutants and electricity production. In this study, the electrochemically active mixed cultures were designated as Culture-FM (fumaric acid), Culture-F (ferric citrate), Culture-S (Na2SO4), and Culture-FS (ferric citrate with Na2SO4), according to the electron acceptors used for enrichment. The phenol degradation efficiency using these cultures exceeded 99 % (with phenol concentration less than 100 mg/L). Among them, the efficiency of phenol degradation at 150–200 mg/L by Culture-FS reached 90 %, which was slightly higher than those of the other cultures. In addition, these cultures were used as inocula to enhance MFC performance with phenol as the sole carbon source. The maximum current density of MFC using Culture-FS was 649.72 μA/cm2 with 100 mg/L phenol, which was 56.16 %, 12.09 % and 18.33 % higher than that using Culture-FM, Culture-F and Culture-S, respectively. These results demonstrate that Culture-FS exhibits superior electricity generation performance using the MFC system. Microbial community analysis indicated that Tolumonas (53.72 %) was the predominant bacterium in Culture-FS, playing the key roles in phenol degradation and electricity production. This study provides valuable insights into enhancing the electricity generation performace with coupling phenol degradation in wastewater treatment using MFC system.