Novosphingobium naphthae sp. nov., from oil-contaminated soil

During the study of hydrocarbon-degrading bacteria in the oil-contaminated soil of Gunsan, North Jeolla Province, South Korea, a light-grey-pigmented, Gram-staining-negative, aerobic, non-motile and rod-shaped bacterium, designated strain D39T, was isolated. This strain was non-sporulating, catalase-negative and oxidase-positive. It was able to grow at 12-42 °C, pH 5.5-8.5 and with 0-1 % (w/v) NaCl. This strain was characterized taxonomically by a polyphasic approach. Based on the results of 16S rRNA gene sequence analysis, strain D39T belongs to the genus Novosphingobium and is closely related to 'Novosphingobium ginsenosidimutans' FW-6 (97.30 % sequence similarity), Novosphingobium mathurense SM117T (97.17 % sequence similarity) and Novosphingobium aquiterrae E-II-3T (97.01 % sequence similarity). The only respiratory quinone was ubiquinone-10 and the major polyamine was spermidine. The polar lipid profile revealed the presence of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, sphingoglycolipid and phosphatidyl-N-methylethanolamine. The predominant fatty acids of strain D39T were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C17 : 1ω6c and C14 : 0 2-OH. The genomic DNA G+C content of this novel strain was 66.7 mol%. The DNA-DNA relatedness between strain D39T and 'N. ginsenosidimutans' KACC 16615, N. mathurense KACC 14598T, N. aquiterrae KACC 17599T and Novosphingobium kunmingense DSM 25975T were 33.7 %, 29.0 %, 22.3 % and 18.3 %, respectively. The morphological, physiological, chemotaxonomic and phylogenetic analyses clearly distinguished this strain from its closest phylogenetic neighbours. Thus, strain D39T represents a novel species of the genus Novosphingobium, for which the name Novosphingobium naphthae sp. nov. is proposed. The type strain is D39T (=KEMB 9005-346T=KACC 18593T=JCM 31158T).