Petroleum-Contaminated Soil Isolates: A Comparative Study of Naphthalene Biodegradation Kinetics and Metabolic Pathways

• Published in: International Journal of Environmental Research 2025-02, Vol.19 (1), Article 40
• Main Authors: Sumathi, K, Manian, Rameshpathy
• Format: Article
• Language: English
• Subjects: Earth and Environmental Science; Environment; Environmental Engineering/Biotechnology; Environmental Management; Geoecology/Natural Processes; Landscape/Regional and Urban Planning; Natural Hazards; Research Paper
• ISSN: 1735-6865; 2008-2304
• DOI: 10.1007/s41742-024-00701-7

In contrast to physical and chemical methods, removal of PAHs like naphthalene through the action of microorganisms offers a safe, affordable, and environmentally beneficial method of remediation. The most popular eradication technique is bioremediation as it is a long-term strategy that completely mineralises naphthalene. Thus, three strains of Citrobacter freundii (VITRPS1), Alcaligenes ammonioxydans (VITRPS2), and Enterobacter cloacae (VITRPS3) isolated from petroleum-contaminated soil carried out the biodegradation of naphthalene in this investigation. The strain VITRPS2 exhibited highest degradation efficiency up to 70.8% for naphthalene and strain VITRPS3 exhibited the lowest with only 14.05%. The degradation rate constant, following first-order kinetics, was determined to be 0.1028 day⁻ 1 , resulting in a half-life of 6.14 days across different naphthalene concentrations. To study the inhibition kinetics of naphthalene, the non-linear Andrew-Haldane model was employed, revealing Vmax, K i , and Kₘ values of 1712/day, 0.005597 mg/mL, and 11,380 mg/mL, respectively, for the strain A. ammonioxydans (VITRPS2). Using Gas chromatography˗mass spectrometry (GC˗MS), this study seeks to determine the specific metabolic pathway of Naphthalene degradation by identifying and analyzing the intermediate metabolites formed during the process, which included salicylic acid, catechol, and several derivatives of phthalic acid. This strain has promising potential and could be useful in the bioremediation of naphthalene-contaminated locations. Highlights Bacteria have been identified from petroleum-contaminated soil. Bacteria are isolated, purified, described, and evaluated for degradation studies. The degrading process will explain the isolate's kinetic mechanism. The Andrew-Haldane model describes first and second order kinetics. Salicylate pathway followed by meta cleavage of catechol.