Effective Removal of Emerging Contaminants from Wastewater by a Novel Manganese-Oxidizing Biofilm System

The presence of antibiotics in natural waters has become a critical socioenvironmental problem due to their propensity for environmental persistence, low removal rates, and detrimental effects on both ecosystems and human health. This study introduces an innovative manganese-oxidizing biofilm system that integrates the biofilm formed by the manganese-oxidizing bacteria Pseudomonas putida MnB1 with manganese sand. Our findings demonstrate that this manganese-oxidizing biofilm can effectively remove the emerging contaminant doxycycline (DOX) from aquatic environments. The manganese-oxidizing biofilm system achieved a high average DOX removal efficiency of 82.36–93.25% across concentrations of 0.1–10 mg·L^–1 over 206 days. In addition, we revealed a strong correlation between contaminant removal and singlet oxygen (¹O₂). Microbial community analysis highlighted the significant role of Pseudomonas putida MnB1 within the microbial community. The manganese-oxidizing biofilm system proposed in this study offers a potent remediation strategy for the purification of medical wastewater contaminated with antibiotics, highlighting the promising application of biodegradation in the realm of water pollution management.