Efficient enriching high-performance denitrifiers using bio-cathode of microbial fuel cells

Recent advancements in microbial fuel cells (MFC) technology have significantly contributed to the development of bio-cathode denitrification as a promising method for eco-friendly wastewater treatment. This study utilized an efficient repeated replacement method to enrich a mixed bio-cathode denitrifying culture (MBD) within a bio-cathode MFC, achieving a stable maximum output voltage of 120 ± 5 mV and a NO₃ ^--N removal efficiency of 69.99 ± 0.60%. The electrotrophic denitrification process appears to be facilitated by electron shuttles. Microbial community analysis revealed a predominance of <i>Proteobacteria</i>, with <i>Paracoccus</i> and <i>Pseudomonas</i> as functional genera. Additionally, the isolated strain Lyy (belonging to <i>Stutzerimonas</i>) from MBD demonstrated exceptional denitrification efficiencies exceeding 98% when treating wastewater with a broad range of C/N (2-12) ratios and KNO₃ concentrations (500-3000 mg/L) within 60 h. These results demonstrated the effectiveness of the repeated replacement method in enriching bio-cathode denitrifiers and advancing MFC application in sustainable wastewater management.