Bioremediation Potential of Microbiota Isolated from Oil-Polluted Ferruginous Soil

Background and Objective: Bioprospecting of microorganisms from hydrocarbon-impacted ecosystems provides a sustainable strategy for identifying indigenous microbial resources suitable for environmental restoration. This study investigated the culturable microbiota associated with crude oil-polluted ferrous soil from Gelegele, Ovia North-East, Edo State, Nigeria. Materials and Methods: The baseline physiochemical characteristic and microbiological diversity of rhizospheric, uncontaminated, and crude oil-contaminated soil samples were examined. The culturable microbial community was assessed for total heterotrophic bacterial and fungal counts, as well as hydrocarbon-utilizing bacterial counts using standard culture-based techniques. The hydrocarbonoclastic strains were screened for biosurfactant production, while Nitrogen-fixing (NF) and phosphate-solubilizing (PS) bacteria were assessed for biodegradation potential. Selected efficient strains were identified molecularly through 16S rRNA gene amplification and sequencing. Results: The contaminated soil recorded a total petroleum hydrocarbon concentration of 9156.57 ppm significantly higher than 105 ppm recorded in uncontaminated soil. All the biosurfactant-producing bacteria demonstrated positive emulsification activity, with indices ranging from 18.4 to 50%. Similarly, all the rhizobacteria exhibited appreciable ammonia production. However, isolate NF1 and PS2 had the highest nitrogen-fixing and phosphate solubilizing activities of 4.1 and 6.8%, respectively. Biosurfactant-producing isolates had higher crude oil degradation efficiency than the phosphate-solubilizing and Nitrogen-fixing bacteria, with petroleum biodegradation potential ranging from 0.304 to 1.834. The most efficient isolates were identified as Pseudomonas putida, Enterobacter cloacae, and Priestiaflexa, with accession numbers PV290867.1, PV290872.1, and PV290876.1, respectively. Conclusion: This study has further identified the environment as a self-sustaining and self-regulating biome. It underscores the enormous benefits in farming microbes from our indigenous communities for the ecological restoration of impacted ecosystems.