Isolation and identification of cyclohexane degrading microorganisms from hydrocarbon contaminated soils

Grace Ngolu Nyalosaso 1, *, Grace Mukendi Mujinga 2, Thierry Musanda 1, 4, Aimé Mawisa 1 and Paul Mobinzo Kapay S 1, 3

1 Nouveaux Horizons University (UNH), Department of Food Sciences, Faculty of Food and Environmental Sciences, Lubumbashi, DR Congo.
2 Faculty of applied and computer sciences, Department of Biotechnology, Vaal University of Technology (VUT), VanderbiljPark, South Africa.
3 University of Lubumbashi (UNILU), Faculty of Veterinary Medicine, Department of Pre-Clinics, Expertise Hygiene and food technology service, Lubumbashi, DR Congo.
4 Faculty of Sciences, Université de Kikwit (UNIKIK), Kikwit, DR Congo.
Research Article
World Journal of Advanced Research and Reviews, 2024, 22(03), 2108–2120
Article DOI: 10.30574/wjarr.2024.22.3.1763
Publication history: 
Received on 02 May 2024; revised on 10 June 2024; accepted on 13 June 2024
Objective: One of the major problems the world is facing nowadays is hydrocarbons pollution due to its detrimental spillage effects on water and soil during transportation. Therefore, assessing and identifying hydrocarbon-degrading bacteria will contribute to the biodegradation of the toxic compounds.
Methods: Pure bacterial cultures were isolated from two different locations, Petrol Depot R57 and Sasol Truck Stop. The soils were excavated from cyclohexane-contaminated areas and then transported to the laboratory for biological analysis. The ability of the bacterial isolates to use cyclohexane as the sole source of carbon was used as a requirement for the identification of the above-mentioned isolates, followed by confirmation of such identity after performing several tests.
Results: Bacterial isolates from Sasol Truck Stop and Petrol Depot R57 were assessed for cyclohexane biodegradation. Bacterial growth was observed at 6% cyclohexane for the Sasol sample but not the Petrol sample due to its toxicity. Both locations required biostimulation at lower concentrations. Morphological and Gram staining differentiated the isolates as followed: Petrol samples had varied bacterial types, while Sasol samples had bacteria only constituted of Gram-positive cocci. Biochemical tests identified varied oxidase, catalase, citrate, indole, lactose fermentation, and motility results. DNA analysis showed contamination during extraction, but effective 16S rRNA amplification and sequencing identified Staphylococcus warneri and Bacillus subtilis, indicating promising bioremediation applications.
Staphylococcus warneri and Bacillus subtilis showcased the potential to degrade cyclohexane as they were able to grow in the highest concentrations.
Conclusion: Identifying bacteria capable of degrading hydrocarbons, like Staphylococcus warneri and Bacillus subtilis, can significantly contribute to bioremediation efforts in reducing hydrocarbons pollution in affected environments.
Bacillus subtilis; Bioremediation; Cyclohexane; Hydrocarbons; Pollution; Staphylococcus warneri
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