Bioaugmentation strategies for polycyclic aromatic hydrocarbons-contaminated intertidal zones: Effects and microbial community succession.

The intertidal zone is one of the natural systems most vulnerable to threats from polycyclic aromatic hydrocarbons (PAHs). However, the natural attenuation rate of PAHs within intertidal zones is low, posing challenges for the short-term recovery of contaminated environments. This study developed a contaminated intertidal zone simulation system and used a composite bacterial consortium containing Cellulosimicrobium sp. RS and Brucella sp. BZ for bioaugmented remediation. The degradation rate of PAHs (initial concentration: 5000 μg/kg) in the sediments reached 85.37 % after 120 days of restoration, which was significantly higher than the 29.93 % observed in the control group. High-throughput sequencing was used to analyze the structure and function of sediment microbial communities. The exogenous bacteria Cellulosimicrobium became dominant after remediation, whereas Brucella did not dominate but contributed to synergistic degradation. Network analysis and PICRUSt predictions confirmed that the microbial community evolved toward stronger PAHs degradation capabilities and degraded PAHs through ring cleavage, side-chain metabolism, and central metabolism in bioaugmented sediments. This study provides theoretical guidance and data support for bioaugmented remediation of intertidal zone pollution.