Sphingomonas naphthae sp. nov., isolated from oil-contaminated soil

Abstract

During the study of hydrocarbon-degrading bacteria in the oil-contaminated soil of Gunsan, North Jeolla Province, South Korea, a yellow, Gram-stain-negative, aerobic, motile, rod-shaped bacterium, designated strain DKC-5-1T, was isolated. This strain was non-sporulating, catalase-negative and oxidase-positive. It was able to grow at 10-33 °C, pH 6.0-8.5 and at an NaCl concentration of 0-1.5 % (w/v). This strain was characterized taxonomically using a polyphasic approach. Based on 16S rRNA gene sequence analysis, strain DKC-5-1T belongs to the genus Sphingomonas and is closely related to Sphingomonas laterariae LNB2T (96.65 % sequence similarity), Sphingomonas haloaromaticamans A175T (96.63 % sequence similarity), Sphingomonas histidinilytica UM2T (96.63 % sequence similarity), and Sphingomonas wittichii RW1T (96.43 % sequence similarity). The only respiratory quinone was ubiquinone-10 and the major polyamine was homospermidine. The polar lipid profile revealed the presence of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, sphingoglycolipid and phosphatidyldimethylethanolamine. The predominant fatty acids of strain DKC-5-1T were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), C16 : 0, C14 : 0 2-OH, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C17 : 1ω6c and C14 : 0. The genomic DNA G+C content of this novel strain was 65.9 mol%. Morphological, physiological, chemotaxonomic and phylogenetic analyses clearly distinguished this strain from its closest phylogenetic neighbours. Thus, strain DKC-5-1T represents a novel species of the genus Sphingomonas, for which the name Sphingomonasnaphthae sp. nov. is proposed. The type strain is DKC-5-1T (=KEMB 9005-380T=KACC 18716T=JCM 31294T).