Competitive metabolism of naphthalene, methylnaphthalenes, and fluorene by phenanthrene-degrading pseudomonads

• Published in: Applied and Environmental Microbiology 1995-01, Vol.61 (1), p.357-362
• Main Authors: Stringfellow, W.T. (University of California, Berkeley, CA.), Aitken, M.D
• Format: Article
• Language: English
• Subjects: Bacteria; Binding, Competitive; BIODEGRADACION; BIODEGRADATION; Biodegradation, Environmental; Biological and medical sciences; Biology; Biology of microorganisms of confirmed or potential industrial interest; Biotechnology; CONTROL DE LA CONTAMINACION; DESINFECTANT; DESINFECTANTES; Enzymes; Fluorenes - metabolism; Fundamental and applied biological sciences. Psychology; HIDROCARBUROS; HIDROCARBUROS AROMATICOS; Hydrocarbons; HYDROCARBURE; HYDROCARBURE AROMATIQUE; LUTTE ANTIPOLLUTION; METABOLISME; METABOLISMO; MINERALISATION; MINERALIZACION; Mission oriented research; Naphthalenes - metabolism; Phenanthrenes - metabolism; Physiology and metabolism; Pollution; POLLUTION DU SOL; POLUCION DEL SUELO; PSEUDOMONAS; Pseudomonas - growth & development; Pseudomonas - metabolism; Pseudomonas stutzeri; SOL ANTHROPOGENE; Spectrophotometry; TIPOS ANTROPOGENICOS DE SUELOS
• ISSN: 0099-2240; 1098-5336
• DOI: 10.1128/aem.61.1.357-362.1995

Polynuclear aromatic hydrocarbons (PAHs) typically exist as complex mixtures in contaminated soils, yet little is known about the biodegradation of PAHs in mixtures. We have isolated two physiologically diverse bacteria, Pseudomonas stutzeri P-16 and P. saccharophila P-15, from a creosote-contaminated soil by enrichment on phenanthrene as the sole carbon source and studied their ability to metabolize several other two- and three-ring PAHs. Naphthalene, 1-methylnaphthalene, and 2-methylnaphthalene served as growth substrates for both organisms, while fluorene was only cometabolized. We also studied the effects of these compounds on initial rates of phenanthrene uptake in binary mixtures. Lineweaver-Burk analysis of kinetic measurements was used to demonstrate competitive inhibition of phenanthrene uptake by all four compounds, suggesting that multiple PAHs are being transformed by a common enzyme pathway in whole cells. Estimates of the inhibition coefficient, Ki, are reported for each compound. The occurrence of competitive metabolic processes in physiologically diverse organisms suggests that competitive metabolism may be a common phenomenon among PAH-degrading organisms