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Characterization of phenol metabolization byP. stutzeriN2 was proposed based on the identification of relevant metabolites and enzyme activities of catechol 1,2-oxygenase and catechol 2,3-dioxygenase.P. stutzeriN2 started to grow on 400 mg l−1phenol with no obvious lag phase, and then phenol decomposition was rapidly completed within 32 h. Results of enzyme activities, UV spectrums of cultures, and the mass spectrum identification of cis, cis-muconic and 2-HMS, which showed that catechol C12O and C23O were acting simultaneously on the fission of the phenol ring. The existence of P-hydroxybenzoic acid and straight-chain saturated dicarboxylic acids in the culture medium showed that carboxylation and hydrogenation were involved during the phenol degradation. Metabolites containing five or four carbons indicated that catechol and its immediate ring-cleavage intermediates could be furthermore metabolized byP. StutzeriN2. Therefore,P. stutzeriN2 which could degrade phenol with high efficiency and diverse pathways could have potential applications in the treatment of wastewater containing phenol. [ABSTRACT FROM AUTHOR]

A new polycyclic aromatic hydrocarbon (PAH)-degrading Gram-negative bacteriumAeromonas salmonicidasubsp.achromogenesstrain NY4 was isolated from coking wastewater sludge. Strain NY4 could not grow on1-hydroxy-2-naphthoic acid, hexadecane or hexanol as sole carbon source but phenanthrene. This strain was able to utilize several known microbial metabolites of PAHs, including catechol, protocatechuic acid, salicylic acid, and phenol as sole carbon source. The mixture of the acidic and neutral fraction, acidic fraction alone and neutral fraction alone of phenanthrene metabolites were prepared and analyzed by GC-MS. A total of at least 27 metabolites were identified as the degradation products of phenanthrene by strain NY4. Among them, 1-hydroxy-α-oxo-2-naphthaleneacetic acid, 2-hydroxy-α-oxo-1-naphthaleneacetic acid, 2-hydroxy-1-(1-hydroxy-2-naphthalenyl)-ethanone, 1,2-dihydro naphtha [2,1-b] furan-2-ol and 2,3-dihydro naphtha [1,2-b] furan-2-ol have not been reported as the metabolites of phenanthrenes so far. The accumulation patterns of phenanthrene metabolite accumulation by strain NY4 depended on the incubation time, inoculum size and concentration of phenanthrene. Based on the degradation metabolites of phenanthrene by strain NY4, degradation pathways are proposed. This is the first report of PAH degradation inAeromonas salmonicida, which lay the foundation for recognition and further characterization of PAH degradation metabolites and pathways inAeromonas salmonicidastrains. [ABSTRACT FROM PUBLISHER]