Corynebacterium hadale sp. nov. isolated from hadopelagic water of the New Britain Trench.

A novel heterotrophic, Gram-stain-positive, facultatively anaerobic and rod-shaped bacterium, designated strain NBT06-6, was isolated from the deep seawater in the New Britain Trench and characterized phylogenetically and phenotypically. Optimal bacterial growth occurred at 35 °C (range 22-41 °C), at pH 6 (4-8) and with 4 % (w/v) NaCl (0-10 %). The strain grew at hydrostatic pressures of 0.1-100 MPa (optimum, 0.1 MPa) at 35 °C. Phylogenetic analysis of the 16S rRNA gene sequences indicated that strain NBT06-6 belonged to the genus Corynebacterium, with the highest sequence similarity (97.9 %) to Corynebacterium imitans, and shared low 16S rRNA gene sequence similarities (<97.0 %) with other type strains. The major respiratory menaquinones were MK-8(H2) and MK-9(H2). The polar lipids were diphosphatidyglycerol, phosphatidylglycerol, phosphatidylinositol, three unidentified aminoglycolipids and four unidentified glycolipids. The major fatty acids detected were C18 : 1ω9c, C16 : 0 and C15 : 0. Strain NBT06-6 contained meso-diaminopimelic acid and mycolic acids in its cell wall, and mannose, galactose, glucose, arabinose and ribose as major whole-cell sugars. The G+C content of the genomic DNA was 65.1 mol%. The digital DNA-DNA hybridization value and the average nucleotide identity between strain NBT06-6 and C. imitans were 24.5±2.4 and 81.9 %, respectively. The combined genotypic and phenotypic data indicated that strain NBT06-6 represents a novel species of the genus Corynebacterium, for which the name Corynebacterium hadale sp. nov. is proposed, with the type strain NBT06-6 (=MCCC 1K03347=DSM 105365).