Evaluating Bacterial Population Changes and Ecological Dynamics in Oil-Impacted Soils Using 16S rRNA Amplicon Sequencing

Abstract

Improper disposal of used motor oil is a prevalent issue in developing countries, leading to a notable contribution to environmental pollution. This study was conducted using the 16S rRNA targeted metagenomic approach, to assess the changes in bacterial population diversity and abundance at an oil contamination experimental site in Botswana. To demonstrate the impact of used motor oil is on the soil ecosystem, soil samples collected at different depths before and after treatment with used motor oil were subjected to total community DNA extraction and Illumina sequencing. The taxonomic bacterial composition data revealed statistically significant differences among the treatments and controls. A notable shift from Gram-negative to Gram-positive bacterial populations was observed following treatment with used motor oil. Prevotella and Aerococcus were among the few genera within the enriched Gram-positive bacteria that could be directly linked to biodegradation of the polycyclic aromatic hydrocarbons associated with oil contamination. Agricultural and biotechnologically important, plant-associated bacterial genera; Methylobacterium-methylorumbrum, Bradyrhizobium, and, Phyllobacterium significantly declined in relative abundance, thus demonstrating the negative impact of oil contamination. The results from this study, improves our understanding of the roles of indigenous soil bacteria, and can help in guiding future strategies for the sustainable management of contaminated soils globally in countries with similar climatic and ecological conditions.