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

Strain CJ2(T), capable of growth on naphthalene as a sole carbon and energy source, was T 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 degreesC (optimum, 20 degreesC) 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-gamma meso-diaminopimelic acid. The major fatty acids of strain CJ2(T) were 16:1omega7c (67.0%), 16:0 (19.6%), 18:1 omega7c (similar to7.9%) and 10:0 3-OH (similar to 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)).