Bioremediation Potential of Indigenous Bacterial Isolates for Treating Petroleum Hydrocarbons-Induced Environmental Pollution

This study isolates oil-degrading bacteria from contaminated soil in automobile workshops, aiming to address environmental pollution from petroleum spills. Nineteen bacterial isolates were screened, with three isolates S4 (<i>Lysinibacillus macroides</i>), M8 (<i>Serratia marcescens</i>), and M9 (<i>S. marcescens</i>), showing significant oil degradation potency. In shake flask assays, S4 degraded 57.8%, M8 60.2%, and M9 58.1% of oil at a 5% concentration. Molecular identification through 16S rRNA gene sequencing confirmed these strains. Plate assays also supported the degradation potential, with growth zones of 38.4 ± 1.3 mm (S4), 39.7 ± 1.9 mm (M8), and 41.2 ± 1.7 mm (M9). Gas chromatography-mass spectrometry analysis of treated oil indicated the presence of hydrocarbons, phenolic compounds, and esters, suggesting microbial interactions, potentially involving the breakdown or transformation of complex hydrocarbons into simpler compounds by bacterial enzymes. These results highlight the potential of these bacterial strains, particularly S4, for the bioremediation of petroleum-contaminated sites.