Sphingomonas oligoaromativorans sp. nov., an oligotrophic bacterium isolated from a forest soil

A halo- and organo-sensitive oligotrophic bacterium, designated strain SY-6T, was isolated from humus forest soil at Gyeryong mountain in Korea. Cells of the strain were Gram-negative, strictly aerobic, non-motile rods and the strain formed yellow-pigmented colonies on 100-fold-diluted nutrient broth. Strain SY-6T grew at pH 6.0-7.0 (optimal growth at pH 7.0), at 10-37 °C (optimal growth at 28 °C) and at salinities of 0-0.5% (w/v) NaCl, growing optimally at 0.01% (w/v) NaCl. On the basis of 16S rRNA gene sequence analysis, strain SY-6T was shown to belong to the genus Sphingomonas and showed the closest phylogenetic similarity to Sphingomonas polyaromaticivorans B2-7T (96.7%). The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine and sphingoglycolipid. The predominant ubiquinone and polyamine were Q-10 and sym-homospermidine, respectively. The major fatty acids were C18:1ω7c and C16:0. The DNA G+C content of the novel isolate was 65.3 mol%. On the basis of the evidence from this polyphasic study, strain SY-6T represents a novel species of the genus Sphingomonas, for which the name Sphingomonas oligoaromativorans sp. nov. is proposed. The type strain is SY-6T (=KACC 12948T=NBRC 105508T).