title: Microbial metabolism of polycyclic aromatic hydrocarbons: isolation and characterization of a pyrene-degrading bacterium.
abstract: Microbiological analyses of sediments located near a point source for petrogenic chemicals resulted in the isolation of a pyrene-mineralizing bacterium. This isolate was identified as a Mycobacterium sp. on the basis of its cellular and colony morphology, gram-positive and strong acid-fast reactions, diagnostic biochemical tests, 66.6% G + C content of the DNA, and high-molecular-weight mycolic acids (C58 to C64). The mycobacterium mineralized pyrene when grown in a mineral salts medium supplemented with nutrients but was unable to utilize pyrene as a sole source of carbon and energy. The mycobacterium grew well at 24 and 30 degrees C and minimally at 35 degrees C. No growth was observed at 5 or 42 degrees C. The mycobacterium grew well at salt concentrations up to 4%. Pyrene-induced Mycobacterium cultures mineralized 5% of the pyrene after 6 h and reached a maximum of 48% mineralization within 72 h. Treatment of induced and noninduced cultures with chloramphenicol showed that pyrene-degrading enzymes were inducible in this Mycobacterium sp. This bacterium could also mineralize other polycyclic aromatic hydrocarbons and alkyl- and nitro-substituted polycyclic aromatic hydrocarbons including naphthalene, phenanthrene, fluoranthene, 3-methylcholanthrene, 1-nitropyrene, and 6-nitrochrysene. This is the first report of a bacterium able to extensively mineralize pyrene and other polycyclic aromatic hydrocarbons containing four aromatic rings.
authors.affiliation: National Center for Toxicological Research, Food and Drug Administration, Jefferson, Arkansas 72079.
authors.forename: M A
authors.initials: MA
authors.lastname: Heitkamp
authors.forename: W
authors.initials: W
authors.lastname: Franklin
authors.forename: C E
authors.initials: CE
authors.lastname: Cerniglia
mesh_terms: D001673:Biodegradation, Environmental; D002855:Chromatography, Thin Layer; D008854:Microscopy, Electron; D009161:Mycobacterium / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure; D011083:Polycyclic Compounds / Q000378:metabolism*; D011721:Pyrenes / Q000378:metabolism*; D014871:Water Microbiology
chemical_list: D011083:Polycyclic Compounds; D011721:Pyrenes