Community pattern of potential phenanthrene (PHE) degrading bacteria in PHE contaminated soil revealed by ¹³C-DNA stable isotope probing

Quantification of polycyclic aromatic hydrocarbons (PAHs) in contaminated soil and identification of potential PAH degraders are essential for comprehending their environmental fate and conducting bioremediation. However, the microbial population responsible for the breakdown of phenanthrene (PHE) in polluted soil environments is frequently disregarded. In this study, via DNA-stable-isotope probing (DNA-SIP), we found that soil microbiota likely plays a crucial part in the PHE degradation. The PHE removal rates were 98% and 99%, in ¹³C-PHE and ¹²C-PHE microcosmic incubations, respectively. ¹³CO₂ was produced along with the degradation of ¹³C-PHE. According to the analysis of 16S rRNA gene, there was a relatively higher presence of unidentified bacteria in the ‘heavy’ DNA fractions treated with ¹³C-PHE. Genus of Enterobacteriales, Acidobacteria, Alphaproteobacteria, Paenibacillaceae, Flavobacteriia, Chloroflexi, Cyanobacteria, Caldilineae, Latescibacteria, Armatimonadetes and Blastocatellia were succseesfully labeled during the degradation of ¹³C-PHE, indicating their capacity of utilizing PHE. Co-occurrence network of ¹³C-heavy fractions exhibited greater complexity compared with that of ¹²C-heavy fractions, revealling an enhancement of bacterial interspecies interactions. Collectivley, this study eluidated the soil microbes involed in the PHE degradation and offered fresh perspectives on the community pattern of potential PHE degrading bacteria.