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Degradation of phenanthrene and anthracene by Nocardia otitidiscaviarum strain TSH1, a moderately thermophilic bacterium
Author(s) -
Zeinali M.,
Vossoughi M.,
Ardestani S.K.
Publication year - 2008
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2008.03753.x
Subject(s) - phenanthrene , nocardia , anthracene , strain (injury) , bacteria , thermophile , microbiology and biotechnology , degradation (telecommunications) , biodegradation , chemistry , actinomycetales , biology , streptomyces , environmental chemistry , organic chemistry , telecommunications , anatomy , computer science , genetics
Aims: The metabolism of phenanthrene and anthracene by a moderate thermophilic Nocardia otitidiscaviarum strain TSH1 was examined. Methods and Results: When strain TSH1 was grown in the presence of anthracene, four metabolites were identified as 1,2‐dihydroxy‐1,2‐dihydroanthracene, 3‐(2‐carboxyvinyl)naphthalene‐2‐carboxylic acid, 2,3‐dihydroxynaphthalene and benzoic acid using gas chromatography‐mass spectrometry (GC‐MS), reverse phase‐high performance liquid chromatography (RP‐HPLC) and thin‐layer chromatography (TLC). Degradation studies with phenanthrene revealed 2,2′‐diphenic acid, phthalic acid, 4‐hydroxyphenylacetic acid, o ‐hydroxyphenylacetic acid, benzoic acid, a phenanthrene dihydrodiol, 4‐[1‐hydroxy(2‐naphthyl)]‐2‐oxobut‐3‐enoic acid and 1‐hydroxy‐2‐naphthoic acid (1H2NA), as detectable metabolites. Conclusions: Strain TSH1 initiates phenanthrene degradation via dioxygenation at the C‐3 and C‐4 or at C‐9 and C‐10 ring positions. Ortho ‐cleavage of the 9,10‐diol leads to formation of 2,2′‐diphenic acid. The 3,4‐diol ring is cleaved to form 1H2NA which can subsequently be degraded through o ‐phthalic acid pathway. Benzoate does not fit in the previously published pathways from mesophiles. Anthracene metabolism seems to start with a dioxygenation at the 1 and 2 positions and ortho ‐cleavage of the resulting diol. The pathway proceeds probably through 2,3‐dicarboxynaphthalene and 2,3‐dihydroxynaphthalene. Degradation of 2,3‐dihydroxynaphthalene to benzoate and transformation of the later to catechol is a possible route for the further degradation of anthracene. Significance and Impact of the Study: For the first time, metabolism of phenanthrene and anthracene in a thermophilic Nocardia strain was investigated.