Hyphobacterium indicum sp. nov., isolated from deep seawater, and emended description of the genus Hyphobacterium

A novel aerobic, Gram-stain-negative bacterium, designated strain 2ED5(T), was isolated from a deep seawater sample in the north-west Indian Ocean. Cells of the strain were oval- to rod-shaped, and motile by a polar flagellum or sessile by a prostheca. The strain formed creamy white colonies on 2216E marine agar plates. It grew at 10-40 degrees C (optimum 28 degrees C) and pH 5.0-8.0 (optimum pH 6.0-7.0). The strain required 1-6 % (w/v) NaCl for growth and grew optimally in the presence of 2-3 % NaCl. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain 2ED5(T) was affiliated with the genus Hyphobacterium in the family Hyphomonadaceae of the class Alphaproteobacteria, sharing 95.1 % similarity at the 16S rRNA gene sequence level with the type strain of Hyphobacterium vulgare, the only species in the genus Hyphobacterium. The major fatty acids of the strain were C-18:1 omega 7c and iso-C-17:1 omega 9c, and the polar lipids included monoglycosyl diglyceride, sulfoquinovosyl diacylglycerol, glucuronopyranosyl diglyceride, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and an unidentified glycolipid. The strain contained ubiquinone Q-10 as the predominant respiratory quinone. The G+C content of the genomic DNA of the strain was 60.9 mol%. Based on the results of this polyphasic analysis, strain 2ED5(T) represents a novel species in the genus Hyphobacterium, for which the name Hyphobacterium indicum sp. nov. is proposed. The type strain is 2ED5(T) (=CGMCC 1.16466(T)=JCM 32612(T)).