Sphingomonas kyungheensis sp. nov., a bacterium with ginsenoside-converting activity isolated from soil of a ginseng field

A bacterial strain THG-B283^T, which has β-glucosidase activity, was isolated from soil of a ginseng field. Cells were Gram-reaction-negative, oxidase- and catalase-positive, aerobic, motile with one polar flagellum and rod-shaped. The strain was subjected to a polyphasic taxonomic study. Strain THG-B283^T grew optimally at around pH 7.0, at 25-28 °C and in the absence of NaCl on R2A agar. 16S rRNA gene sequence analysis revealed that strain THG-B283^T belongs to the family Sphingomonadaceae and is closely related to Sphingomonas melonis DAPP-PG 224^T (98.2 %), S. aquatilis JSS7^T (98.1 %), S. insulae DS-28^T (97.6 %), S. mali IFO 15500^T (97.1 %) and S. pruni IFO 15498^T (97.0 %). Strain THG-B283^T contained Q-10 as the predominant ubiquinone. The major fatty acids included summed feature 3 (comprising C_{16: 1}ω7c and/or C_{16: 1}ω6c), C_{18: 1}ω7c, C_{14: 0} 2-OH and C_{16: 0}. The DNA G+C content was 72.2 mol%. The major component in the polyamine pattern was sym-homospermidine. The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, phosphatidyldimethylethanolamine, phosphatidylcholine, sphingoglycolipid, diphosphatidylglycerol, an unidentified glycolipid, unidentified aminolipids, an unidentified phospholipid and unidentified lipids. Genomic and chemotaxonomic data supported the affiliation of strain THG-B283^T to the genus Sphingomonas. DNA-DNA relatedness between strain THG-B283^T and its closest phylogenetic neighbours was below 23 %. On the basis of phenotypic, phylogenetic and genetic data, strain THG-B283^T represents a novel species of genus Sphingomonas, for which the name Sphingomonas kyungheensis sp. nov. is proposed. The type strain is THG-B283^T (=KACC 16224^T=LMG 26582^T).