Microbial communities in field-scale oil-polluted soil remediation using 16S rRNA amplicon sequencing

Abstract

This investigation employed 16S rRNA amplicon sequencing to understand microbial dynamics during a 2-month field-scale oil-impacted soil remediation in the Niger Delta. Surface soil (0.0-0.5 m) had extractable total petroleum hydrocarbons (ETPH) concentrations of 6231 mg/kg and subsurface samples from 1.0 m, 1.5 m and 2.0 m depths had 4836 mg/kg, 9112 mg/kg and 7273 mg/kg, respectively. Proteobacteria dominated the bacterial community of the oil-polluted soil and comprised mainly Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria. Alpha diversity analysis revealed the presence of hydrocarbons reduced microbial diversity. Principal coordinate analysis indicated that the community structure continually changed following variations in the ETPH concentrations. Mycobacterium, Burkholderia, Methylobacterium and Bacillus were among the core operational taxonomic units (OTUs) detected during remediation. Significant variation in predicted pathway abundance, particularly pathways for fatty acid metabolism, propanoate, benzoate, polycyclic aromatic hydrocarbons, naphthalene and xenobiotics degradation, was more apparent in samples obtained during remediation than in the reference control