Microbial functional shifts in a paradigmatic petrochemical brownfield: Mechanisms of adaptation in soil and groundwater.

The long-term presence of pollutants from the petrochemical industry, including benzene, nitro compounds, and amine-based aromatics, poses a significant threat to soil and groundwater, resulting in shifts in microbial community structures. In this study, 48 soil and groundwater samples from contaminated environments were analyzed using metagenomic technology and gas chromatography-mass spectrometry to examine the metabolic strategies employed by microorganisms in response to these pollutants. The results revealed that microbial community composition was significantly influenced by varying contamination levels, primarily determined by the distance from contamination sources and the diffusion characteristics of the environmental media. In highly contaminated areas, specific bacterial genera, including Pseudomonas and Stutzerimonas, became dominant, suggesting an adaptation toward pollutant degradation. Soil and groundwater microorganisms exhibited distinct adaptive mechanisms: in soils, enhanced motility, metabolism, and toxicant transport were associated with the expression of genes such as mcp, tktA, and pleD, while in groundwater, pollutant degradation and the maintenance of cellular function were driven by genes including xylA, dmpB, nfnB, and glnA. These findings emphasise the capacity of microbes to adapt to pollutants from petrochemical industry environments, thus providing valuable insights into microbial remediation strategies for environmental pollution management.