Microbaculum marinum gen. nov., sp. nov., isolated from deep seawater.

A Gram-stain-negative, aerobic, rod-shaped and non-motile bacterium, designated HSF11T, was isolated from deep seawater of the South China Sea. Growth was observed at 20-40 °C (optimum 35 °C), pH 5.0-8.5 (optimum pH 7.0-7.5) and with 0-7 % NaCl (optimum 2 %). Bacteriochlorophyll a and poly-β-hydroxybutyrate (PHB) granules were not detected. Nitrate could be reduced to nitrite. The major fatty acids (≥5 %) of strain HSF11T were C19 : 0cyclo ω8c, C18 : 0 and C16 : 0. The isoprenoid quinone was Q-10. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, two unknown phospholipids (PL1, PL2), one unknown aminolipid (AL1) and three unknown lipids (L1, L3, L4). The genomic DNA G+C content was 70.7 mol%. 16S rRNA gene sequence analysis indicated that strain HSF11T was most closely related to Tepidamorphus gemmatus DSM 19345T (95.7 % 16S rRNA gene sequence similarity) and Lutibaculum baratangense KCTC 22669T (95.2 %). On the basis of the genotypic, phenotypic, phylogenetic and chemotaxonomic characteristics, strain HSF11T represents a novel species of a new genus, for which the name Microbaculum marinum gen. nov., sp. nov. is proposed. The type strain of the type species is HSF11T (=KCTC 52 363T=MCCC 1K03192T).