Degradation of phenanthrene and anthracene by cell suspensions of Mycobacterium sp strain PYR-1

Cultures of Mycobacterium sp. strain PYR-1 were dosed with anthracene or ph enanthrene and after 14 days of incubation had degraded 92 and 90% of the a dded anthracene and phenanthrene, respectively. The metabolites were extrac ted and identified by UV-visible light absorption, high-pressure liquid chr omatography retention times, mass spectrometry, H-1 and C-13 nuclear magnet ic resonance spectrometry, and comparison to authentic compounds and litera ture data. Neutral-pH ethyl acetate extracts from anthracene-incubated cell s showed four metabolites, identified as cis-1,2-dihydroxy-1,2-dihydroanthr acene, 6,7-benzocoumarin, 1-methoxy-2-hydroxyanthracene, and 9,10-anthraqui none. A novel anthracene ring fission product was isolated from acidified c ulture media and was identified as 3-(2-carboxyvinyl)naphthalene-2-carboxyl ic acid. 6,7-Benzocoumarin was also found in that extract. When Mycobacteri um sp. strain PYR-1 was grown in the presence of phenanthrene, three neutra l metabolites were identified as cis- and trans-9,10-dihydroxy-9,10-dihydro phenanthrene and cis-3,4-dihydroxy-3,4 dihydrophenanthrene. Phenanthrene ri ng fission products, isolated from acid extracts, were identified as 2,2'-d iphenie acid, 1-hydroxynaphthoic acid, and phthalic acid. The data point to the existence, next to already known routes for both gram-negative and gra m-positive bacteria, of alternative pathways that might be due to the prese nce of different dioxygenases or to a relaxed specificity of the same dioxy genase for initial attack on polycyclic aromatic hydrocarbons.