Electricity generation and microbial community in long-running microbial fuel cell for high-salinity mustard tuber wastewater treatment.

High-salinity mustard tuber wastewater (MTWW) was utilized to obtain effluent treatment and recover bio-energy simultaneously in a microbial fuel cell (MFC). Since the long-term performance of MFCs in MTWW remains unclear, this study examined electricity generation and the microbial community that developed over a 195-day test. The MFC produced electricity over the entire testing period, with stable power output obtained on days 32-120. In the stable phase, a maximum power density of 12.43 W·m-3 was observed, and the internal resistance, open circuit voltage, and columbic efficiency (CE) were 148 Ω, 756 mV and 36.7 ± 1.2%, respectively. Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD) removal continuously increased to 89.0 ± 1.5% and 98.6 ± 2.0%, respectively, the maximum rates that were obtained at the end of the experiment, respectively. In addition, 16S rRNA gene sequencing analysis showed that hydrolytic/fermentative bacteria could be considered as the bioanode core microbiome, constituting 36.90% of the microbiome. Sulfate-reducing bacteria (SRB), including Dethiosulfovibrio, Thermovirga, Desulfovibrio, and Desulfuromonas, eventually outcompeted the exoelectrogens completely, causing an irreversible loss in CE. This study provides more ideas for treatment and utilization of high-salinity MTWW.