Sphingomicrobium lutaoense gen. nov., sp. nov., isolated from a coastal hot spring

Abstract

A yellowish pigmented, Gram-negative, rod-shaped, non-spore-forming bacterium (strain CC-TBT-3(T)), was isolated on marine agar 2216 from a coastal hot spring of Green Island (Lutao), located off Taituang, Taiwan. 16S rRNA gene sequence analysis of strain CC-TBT-3(T) showed a relatively low similarity (<95.5 %) to representatives of the genera Novosphingobium, Sphingosinicella and Sphingomonas of the Sphingomonadaceae, with the most related strain being the type strain of Novosphingobium soli. In addition to the relatively low 16S rRNA gene sequence similarity to members of established species, the isolate also showed some unique chemotaxonomic features, including the presence of some glycolipids with unusual chromatographic behaviour. The major components of the polar lipid profile were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, sphingoglycolipid and three unidentified glycolipids. The major respiratory quinone was ubiquinone Q-10. The polyamine pattern was characterized by the triamine sym-homospermidine as a major component. Although the predominant fatty acids were C(18:1)ω7c and summed feature 3 (C(16:1)ω7c and/or iso-C(15:0) 2-OH), the isolate did not show the typical hydroxyl fatty acids, such as C(14:0) 2-OH, C(15:0) 2-OH and C(16:0) 2-OH, found in members of the genera Novosphingobium, Sphingomonas and Sphingosinicella, but showed instead high amounts of C(18:1) 2-OH (12.0 %). The DNA G+C content of strain CC-TBT-3(T) was 63.4 mol%. 16S rRNA gene sequence, chemotaxonomic and physiological analyses revealed that strain CC-TBT-3(T) represents a novel species in a new genus in the family Sphingomonadaceae for which the name Sphingomicrobium lutaoense gen. nov., sp. nov. is proposed; the type strain is of the type species S. lutoaense, CC-TBT-3(T) ( = DSM 24194(T) = CCM 7794(T)).