Thalassomonas eurytherma sp. nov., a marine proteobacterium.

Two Gram-staining-negative, aerobic, rod-shaped bacterial strains, designated Za6a-12(T) and Za6a-17, were isolated from seawater of the East China Sea. Cells of Za6a-12(T) and Za6a-17 were approximately 1.5-2.0 µm×0.5-0.7 µm and motile by a single polar flagellum. Strains grew optimally at pH 7.5-8.0, 28 °C, and in the presence of 2.5-3.0% (w/v) NaCl. Chemotaxonomic analysis showed that the predominant respiratory quinone of strains Za6a-12(T) and Za6a-17 was ubiquinone-8 (>97%), and the major fatty acids were C(14 : 0), C(16 : 1)ω7c and/or iso-C(15 : 0) 2-OH, C(16 : 0) and C(17 : 1)ω8c. Their DNA G+C contents were 42.7 mol% and 42.8 mol%, respectively. 16S rRNA gene sequence analysis revealed that the isolates belonged to the genus Thalassomonas and showed the highest sequence similarity to Thalassomonas loyana CBMAI 722(T) (95.9%). Strains Za6a-12(T) and Za6a-17 could be differentiated from T. loyana CBMAI 722(T) according to their phenotypic and chemotaxonomic features, DNA G+C contents and fatty acid composition. On the basis of these features, we propose strains Za6a-12(T) and Za6a-17 to be representatives of a novel species of the genus Thalassomonas with the name Thalassomonas eurytherma sp. nov. suggested. Strain Za6a-12(T) ( = CGMCC 1.12115(T) = JCM 18482(T)) is the type strain of this novel species.