Microbiome and imputed metagenome study of crude and refined petroleum-oil-contaminated soils: Potential for hydrocarbon degradation and plant-growth promotion

Microbial community structure of crude petroleum oil (CP)- and refined petroleum oil (RP)-contaminated soil wasinvestigated. The taxonomical and functional diversity of such soils can be a great source of information about microbialcommunity and genes involved in petroleum hydrocarbon (PHC) degradation. In this study, microbial diversity of soilscontaminated by RP from urban biome of Pune, India, and CP from agricultural biome of Gujarat, India, were assessed by16S rRNA amplicon sequencing on Illumina MiSeq platform. Association between the soil microbial community and thephysicochemical parameters were investigated for their potential role. In RP- and CP-contaminated soils, the microbiomeanalysis showed Proteobacteria as most dominant phylum followed by Actinobacteria. Interestingly, Firmicutes were mostprevailing in a CP-contaminated sample while they were least prevailing in RP-contaminated soils. Soil moisture content,total organic carbon and organic nitrogen content influenced the taxa diversity in these soils. Species richness was more inRP as compared to CP soils. Further prediction of metagenome using PICRUSt revealed that the RP and CP soils containmicrobial communities with excellent metabolic potential for PHC degradation. Microbial community contributing to genesessential for soil health improvement and plant growth promotion was also gauged. Our analysis showed promising resultsfor future bioaugmentation assisted phytoremediation (BAP) strategies for treating such soils.