Profiling of Hydrocarbon Degrading Bacteria Species Isolated From Hydrocarbon-Polluted Wastewater

Oil exploration and extraction wastewater is composed of organic hydrocarbons like aromatic and aliphatic hydrocarbons such that oil spillage and contamination of water pose great risk to humans and the ecosystem. This research is aimed at profiling indigenous hydrocarbon-utilizing microorganisms isolated from hydrocarbon polluted wastewater. Microorganisms indigenous to refinery effluents were isolated using nutrient agar and kings B medium and identified by standard morphological and biochemical tests, and confirmed by molecular characterisation. The isolates were screened for hydrocarbon degradation potential using Bushnell-Haas medium incorporated with 1% crude oil. The isolates identified were species of Pseudomonas, Enterobacter, Bacillus, Corynebacterium, Proteus, Staphylococcus, Streptococcus, Achromobacter and Escherichia. Pseudomonas was the most prevalent (20.9 %) whileStreptococcus was the least (3.6%). The 16S rRNA of some of the isolates showed a percentage similarity to other species at 100%. The evolutionary distances computed were in agreement with the phylogenetic placement of the 16S rRNA of the isolates within the Proteus, Escherichia, Pseudomonas, Bacillus and Enterobacter sp. and revealed a closely relatedness to the Proteus columbae, Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus and Enterobacter mori. Of the isolates, Enterobacter sp., Bacillus sp., Pseudomonas sp., were shown to have great potential in degrading petroleum hydrocarbons when grown on Bushnell Haas medium. Compared to the other isolates, Pseudomonas sp. had the best growth in Bushnell Haas medium. These microorganisms native to the hydrocarbon polluted wastewater could be employed in the clean-up of hydrocarbon polluted wastewater.