A soil bacterium capable of utilizing fluoranthene as the sole source of carbon and energy for growth was purified from a seven-member bacterial community previously isolated from a creosote waste site for its ability to degrade polycyclic aromatic hydrocarbons. By standard bacteriological methods, this bacterium was characterized taxonomically as a strain of Pseudomonas paucimobilis and was designated strain EPA505. Utilization of fluoranthene by strain EPA505 was demonstrated by increase in bacterial biomass, decrease in aqueous fluoranthene concentration, and transient formation of transformation products in liquid cultures where fluoranthene was supplied as the sole carbon source. Resting cells grown in complex medium showed activity toward anthraquinone, benzo[b]fluorene, biphenyl, chrysene, and pyrene as demonstrated by the disappearance of parent compounds or changes in their UV absorption spectra. Fluoranthene-grown resting cells were active against these compounds as well as 2,3-dimethylnaphthalene, anthracene, fluoranthene, fluorene, naphthalene, and phenanthrene. These studies demonstrate that organic compounds not previously reported to serve as growth substrates can be utilized by axenic cultures of microorganisms. Such organisms may possess novel degradative systems that are active toward other compounds whose biological degradation has been limited because of inherent structural considerations or because of low aqueous solubility.

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An anaerobic bacterial coculture which dechlorinated 3-chlorobenzoate (3CB) to benzoate was obtained by single-colony isolation from an anaerobic bacterial consortium which completely degraded 3CB in defined medium. Of 29 additional halogenated aromatic compounds tested, the coculture removed the meta halogen from 2,3-and 2,5-dichlorobenzoate, 3-bromobenzoate (3BB), 5-chlorovanillate (5CV), and 3-chloro-4-hydroxybenzoate. Dechlorinating activity in the coculture required the presence of pyruvate. 5CV was also O-demethoxylated. The coculture contained two cell types: a short, straight gram-negative rod and a long, thin, curved gram-positive rod. The short rod, Desulfomicrobium escambiense, was recently isolated and identified as a new sulfate-reducing bacterial species (