Biosurfactant Producing Potential of Bacteria Isolated from Sediment of Crude Oil Contaminated Iko River Estuary, Nigeria

There are several physical, chemical, and biological methods to remove petroleum hydrocarbons from contaminated environments. Biological processes are considered the most exciting, cost-effective, and environmentally friendly approaches for removing petroleum hydrocarbons compared to chemical or physical processes. Biosurfactants enhance the bioavailability of hydrophobic organic compounds, making them effective agents for environmental cleanup. Hence, this study aimed to isolate biosurfactant-producing bacteria from the estuarine sediment of the crude oil-contaminated Iko River estuary capable of degrading petroleum hydrocarbons using appropriate methods. The results revealed that Pseudomonas aeruginosa, Bacillus subtilis, Micrococcus spp. and Bacillus spp. exhibited haemolytic activity. All organisms except Bacillus cereus were positive for the emulsification, drop collapse, and oil spread tests. However, Pseudomonas aeruginosa demonstrated the highest emulsification capacity, followed by Bacillus subtilis, Micrococcus spp., Bacillus spp., and Bacillus cereus, respectively. Degradation of crude oil and its components was faster when enhanced with a mixed culture of Bacillus subtilis and Pseudomonas aeruginosa than with individual bacterial isolates. Bacillus subtilis reduced the crude oil component from 257.27 mg/l to 120.42 mg/l. Pseudomonas aeruginosa reduced crude oil component 257.27 mg/l to 48.41 mg/l, whereas the mixed culture of Bacillus subtilis and Pseudomonas aeruginosa reduced crude oil components from 257.27 mg/l to 7.82 mg/l. Biosurfactant-producing bacteria with hydrocarbon-utilising capacity have the potential to enhance the biodegradation of total petroleum hydrocarbons. The key to increasing hydrocarbon degradation rates is bioaugmentation with a biosurfactant-producing bacterial consortium that can act synergistically to degrade hydrocarbons more effectively.