Polaromonas naphthalenivorans sp. nov., a naphthalene-degrading bacterium from naphthalene-contaminated sediment

Department of Microbiology, Cornell University, Ithaca, NY 14853-8101, USA Correspondence Eugene L. Madsen elm3{at}cornell.edu Strain CJ2 T , capable of growth on naphthalene as a sole carbon and energy source, was isolated from coal-tar-contaminated freshwater sediment. The Gram reaction of strain CJ2 T was negative. The cells were non-spore-forming, non-motile cocci (without flagella). The isolate was found to be an aerobic heterotroph capable of utilizing glucose and other simple sugars. Growth was observed between 4 and 25 °C (optimum, 20 °C) and between pH 6·0 and 9·0 (optimum, pH 7·0–7·5). The G+C content of the genomic DNA was 61·5 mol% and the major quinone was ubiquinone-8. The peptidoglycan of strain CJ2 T was determined as belonging to type A1- , meso -diaminopimelic acid. The major fatty acids of strain CJ2 T were 16 : 1 7 c (67·0 %), 16 : 0 (19·6 %), 18 : 1 7 c ( 7·9 %) and 10 : 0 3-OH ( 2·5 %). The polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. Mycolic acid and glycolipids could not be detected. Comparative 16S rDNA analysis indicated that strain CJ2 T is related to the family Comamonadaceae and that the nearest phylogenetic relative was Polaromonas vacuolata 34-P T (97·1 % similarity). On the basis of the physiological and molecular properties, the naphthalene-degrading isolate was designated Polaromonas naphthalenivorans sp. nov. The type strain is CJ2 T (=ATCC BAA-779 T =DSM 15660 T ). Abbreviations: MSB agar, minimal salts base agar; PAH, polycyclic aromatic hydrocarbon; PHA, poly- -hydroxyalkanoic acid Published online ahead of print on 18 July 2003 as DOI 10.1099/ijs.0.02636-0. The GenBank accession number for the 16S rDNA sequence of strain CJ2 T is AY166684 . Micrographs of strain CJ2 T , growth curves in various media and details of aromatic hydrocarbon metabolism are available as supplementary material in IJSEM Online.