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(16-29) Degradation of three-ring azaarenes by Sphingomonas sp. LH128. de Graaf, Chris1, van Herwijnen, Rene1, Parsons, John*,1, 1 IBED-Environmental and Toxicological Chemistry, Amsterdam, The Netherlands ABSTRACT- Although azaarenes, a group of N-heterocyclic PAHs, are widely distributed in the environment, little is know about their microbial degradation. In this study we have investigated the degradation of three-ring azaarenes by the phenanthrene-degrading soil bacterium Sphingomonas sp. LH128. All five compounds studied (acridine, 9-methylacridine, benzo[f]quinoline, benzo[h]quinoline, phenanthridine) were degraded rapidly by this strain, although the strain did not grow on the compounds. There was evidence that the degradation of acridine and benzo[h]quinoline was inhibited at the highest concentrations used. Michaelis-Menten kinetic parameters were estimated for all five compounds and compared to the scarce literature data. At low substrate concentrations, pseudo-first order half lives were estimated to be between 1 and 50 days. In addition, the metabolites formed during degradation were identified using GC-MS analysis. Key words: Biodegradation, Azaarenes, Kinetics, PAHs |
