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

Abstract

Strain CJ2T, 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 CJ2Twas 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 CJ2Twas determined as belonging to type A1-γ,meso-diaminopimelic acid. The major fatty acids of strain CJ2Twere 16 : 1ω7c(67·0 %), 16 : 0 (19·6 %), 18 : 1ω7c(∼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 CJ2Tis related to the familyComamonadaceaeand that the nearest phylogenetic relative wasPolaromonas vacuolata34-PT(97·1 % similarity). On the basis of the physiological and molecular properties, the naphthalene-degrading isolate was designatedPolaromonas naphthalenivoranssp. nov. The type strain is CJ2T(=ATCC BAA-779T=DSM 15660T).