[Degradation Process of Exogenous Naphthenic Acids and Their Effects on Microbial Community Structure in Soil]

Naphthenic acids (NAs) are a natural component of petroleum, which account for about 2% of severe ecological toxicity in addition to polycyclic aromatic hydrocarbons. With the growth in demand for energy, a large number of NAs have leaked into soil environments through oil industry processes, which have caused enormous potential threats to human health and ecosystems. However, there are few studies about the degradation process of exogenous NAs and their effects on microbial community structures in soil. This research explores the degradation process of NAs and their dynamics in microbial communities in soil by adding a high concentration of 180 mg·kg^-1 of NAs to natural, clean soil with the aid of liquid chromatography and high-throughput sequencing technologies. This study found that:① Natural clean soil has a strong capability to degrade high concentration of NAs with about 50% of the NAs degraded within 5 days, which stabilized at 80% after 30 days of the experiment; ② Pollution with NAs obviously alters the microbial community structure as the number of specific OTU increased and were mainly distributed in phylum of unidentified Proteobacteria and Bacteroidetes; ③ Under high concentrations of NAs, the content of Bacteroidetes and Acidobacteria phylum and the γ-Proteobacteria of Proteobacteria phylum all increased swiftly and were speculated to be a potential agents for NA degradation, with the relative abundance ratio of Bacteroidetes and Acidobacteria increasing from 4.2% and 2% to 20.3% and 5.5%, respectively, while a 24.8% decrease was found in Actinobacteria phylum; ④ This study revealed the degradation process of exogenous NAs and their effects on microbial community structure in soil, which provided scientific support for the ecological restoration of petroleum pollution and further study in this area.