# Microbial Diversity, Co-Occurrence Patterns, and Functional Genes of Bacteria in Aged Coking Contaminated Soils by Polycyclic Aromatic Hydrocarbons: Implications to Soil Health and Bioremediation

## TL;DR

This study explores how bacteria in PAH-contaminated soils from an old coking plant respond, focusing on their diversity, interactions, and genes involved in breaking down pollutants.

## Contribution

The study identifies specific bacteria and functional genes linked to PAH degradation in aged contaminated soils.

## Key findings

- Proteobacteria were significantly correlated with PAHs in contaminated soils.
- The phn gene cluster was highly expressed in soils from the coking production area.
- Microbial network analysis revealed key species and interactions in PAH-contaminated soils.

## Abstract

PAH contamination from coking plants have received widespread attention. However, the microbial diversity, co-occurrence patterns, and functional genes of bacteria in aged coking contaminated soils by PAHs are still not clear. In our study, we used a macro-genetic approach to detect PAH-contaminated soils from both a coking production area (CA group) and an office zone (OA group) in an abandoned coking plant, and analyzed the characteristic bacteria and function genes, microbial network interaction patterns, and soil P-cycling in long-term PAH-contaminated soils. The results revealed that Proteobacteria were significantly positively correlated with PAHs and Betaprobacteria bacterium rifcsplowo2 12 full 6514, candidatus Muproteobacteria bacterium RBG16609, and Sulfurifustis variabilis, which belong to Proteobacteria, were characteristic bacteria in PAH-contaminated soils. The phn, which is the PAH degradation gene, was abundantly expressed in the PAH-contaminated soil. The phn gene cluster genes (phnE, phnC, and phnD) were significantly expressed in the CA group of PAH-contaminated soils (p < 0.05). By integrating microbial diversity, network structure, and functional genes, it offers a comprehensive understanding of soil ecosystem response indicators to prolonged PAH stress. The results of this study will provide new ideas for constructing an assessment index system for soil health and screening biomarkers for PAH-contaminated soils.