Microbial desalination using Advenella faeciporci ZF1 as a novel iron-reducing bacterium isolated from oil refinery sludge

Advenella faeciporci strain ZF1, a newly isolated iron-reducing bacterium obtained from Esfahan Oil Refining sludge, exhibited remarkable tolerance to FeCl₃ (up to 20 g/L) and pronounced electrochemical activity under both aerobic and anaerobic conditions. Phylogenetic identification and physiological characterization were performed using 16 S rRNA gene sequencing, Fourier-transform infrared (FTIR) spectroscopy, polyhydroxybutyrate (PHB) staining, and magnetotaxis assays. When integrated into a three-chamber microbial desalination cell (MDC), strain ZF1 achieved removal efficiencies of 70.6% for Na⁺, 78.6% for Ca²⁺, and 27.5% for Cl⁻ from real refinery brine over 15-days operation period. Under moderate salinity condition (9 g/L NaCl), the MDC generated a maximum voltage of 410 ± 15 mV within 48 h. The corresponding peak power density reached 92 ± 5 mW m^− 2 at an external resistance of 100 Ω with a current density of 1.80 ± 0.10 mA m^− 2. These results identify A. faeciporci ZF1 as a robust and extremotolerant exoelectrogen with significant potential for integrated desalination and bioremediation of metal-rich industrial wastewater.