Application of high-performance liquid chromatography/high resolution mass spectrometry for investigation of biodegradation and transformation of phenanthrene by a plasmid bearing rhizosphere bacteria Pseudomonas aureofaciens
T15N2
A.M. Zyakun, V.V. Kochetkov, V.N. Zakharchenko, B.P. Baskunov, V.P. Peshenko,
K.S. Laurinavichius, T.V. Siunova, T.O. Anokhina, A.M. Boronin
Mass spectrometry was applied to identify metabolites and estimate efficiency of phenanthrene biodegradation and transformation by rhizosphere bacteria Pseudomonas aureofaciens BS1393. The strains P. aureofaciens BS1393(pOV17) and P. aureofaciens BS1393(NPL-41) bearing various naphthalene biodegradation plasmids were used in the work. The strain BS1393(pOV17) contains the pOV17 wild type naphthalene biodegradation plasmid that determine oxidation of naphthalene to Krebs cycle metabolites. The strain BS1393(NPL-41) contains the mutant plasmid NPL-41 governing the initial stages of naphthalene oxidation into salicylic acid. The limiting stages of phenanthrene biodegradation in bacteria with various plasmids have been identified according to intermediates accumulation. When bacteria was grown on phenanthrene, the main metabolites were as follows: (a) 2-hydroxy-2H-benzo[h]chromene-2-carboxylic acid/trans-4-(1-hydroxynaph-2-yl)-2-oxobut-3-enoic acid, (b) 1-hydroxy-2-naphthoic acid and (c) salicylic acid. In strain BS1393(pOV17) metabolite (а) was observed during 1–14 days of cultivation. Unlike it, in strain BS1393(NPL-41) an insignificant amount of this metabolite was found after only 14 days. Availability of metabolite (b) during the growth of both strains is an evidence of limited rate of its further decarboxylation. Metabolite (c) as a final product was found during growth of strain BS1393(NPL-41). Contrastingly, in strain BS1393(pOV17) this metabolite was absent, which indicates the complete oxidation of phenanthrene.
