Maribacter hydrothermalis sp. nov., Isolated from Shallow-Sea Hydrothermal Systems Off Kueishantao Island

A Gram-stain-negative, strictly aerobic, yellow-pigmented bacterial strain, designated as T28(T), was isolated from seawater of the shallow-sea hydrothermal system, Kueishantao Islet, Taiwan, China. Cells were oxidase-negative and catalase-positive rods without gliding motility. Growth was observed at 10-40 degrees C (optimum, 30 degrees C), at pH 5.0-8.0 (optimum, pH 6.0) and in the presence of 0-5% (w/v) NaCl (optimum, 2.5%). Strain T28(T) contained menaquinone 6 as the only isoprenoid quinone. The main cellular fatty acids were iso-C-15:0, iso-C-15:1 G, and iso-C(17:0)3-OH, summed feature 3 (C-16:1 omega 7c/omega 6c). Polar lipids contain diphosphatidylglycerol, phosphatidylethanolamine, two unidentified phospholipids, six unidentified lipids, an unidentified aminolipid, and one unidentified aminophospholipids. The genomic DNA G + C content was 34.4 mol%. The 16S rRNA gene sequence of strain T28(T) shared highest similarity with Maribacter arcticus (97.7%). Phylogenetic analysis based on 16S rRNA gene sequences revealed that the strain T28(T) belongs to the genus Maribacter. On the basis of phylogenetic data and several distinct phenotypic characteristics, strain T28(T) represents a novel species, for which the name Maribacter hydrothermalis sp. nov. is proposed. The type strain is T28(T) (=CGMCC 1.15788(T) = JCM 31510(T)).