ACTIONS OF A VERSATILE FLUORENE-DEGRADING BACTERIAL ISOLATE ON POLYCYCLIC AROMATIC-COMPOUNDS

Pseudomonas cepacia F297 grew with fluorene as a sole source of carbon and energy; its growth yield corresponded to an assimilation of about 40% of fluorene carbon. The accumulation of a ring meta-cleavage prod uct during growth and the identification of 1-indanone in growth media and washed-cell suspensions suggest that strain E297 metabolizes fluo rene by mechanisms analogous to those of naphthalene degradation. In a ddition to fluorene, strain F297 utilized for growth a wide variety of polycyclic aromatic compounds (PACs), including naphthalene, 2,3-dime thylnaphthalene, phenanthrene, anthracene, and dibenzothiophene. Fluor ene-induced cells of the strain also transformed 2,6-dimethylnaphthale ne, biphenyl, dibenzofuran, acenaphthene, and acenaphthylene. The iden tification of products formed from those substrates (by gas chromatogr aphy-mass spectrometry) in washed-cell suspensions indicates that P. c epacia F297 carries out the following reactions: (i) aromatic ring oxi dation and cleavage, apparently using the pyruvate released for growth , (ii) methyl group oxidations, (iii) methylenic oxidations, and (iv) S oxidations of aromatic sulfur heterocycles. Strain F297 grew with a creosote-PAC mixture, producing an almost complete removal of all arom atic compounds containing 2 to 3 rings in 14 days, as demonstrated by gas chromatography analysis of the remaining PACs recovered from cultu res. The identification of key chemicals confirmed that not only are c ertain compounds depleted but also the anticipated reaction products a re found.