Efficient low-temperature wastewater treatment by Pseudomonas zhanjiangensis sp. nov.: a novel cold-tolerant bacterium isolated from mangrove sediment

A novel heterotrophic, cold-tolerant bacterium, designated <i>Pseudomonas zhanjiangensis</i> 25A3E^T, was isolated from mangrove sediment and demonstrated excellent efficiency in cold wastewater treatment. Phylogenetic analysis based on 16S rRNA gene sequences positioned strain 25A3E^T within the genus <i>Pseudomonas</i>, showing the highest similarity (98.7%) with <i>Pseudomonas kurunegalensis</i> LMG 32023^T. Digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values were below the species delineation thresholds (70% for dDDH, 95% for ANI), indicating that strain 25A3E^T represents a novel species. This strain demonstrated high efficiency in removing nitrogen (N) and organic pollutants under low-temperature conditions. Specifically, it achieved 72.9% removal of chemical oxygen demand (COD), 70.6% removal of ammoniacal nitrogen (NH₄ ⁺-N), and 69.1% removal of total nitrogen (TN) after 96 h at 10°C. Genomic analysis identified key genes associated with cold adaptation, nitrogen removal and organic matter degradation. These findings indicate that <i>Pseudomonas zhanjiangensis</i> 25A3E^T holds significant potential for application in cold temperature wastewater treatment, offering a promising solution for environmental remediation in regions with low ambient temperatures.