Zhangella mobilis gen. nov., sp. nov., a new member of the family Hyphomicrobiaceae isolated from coastal seawater.

A Gram-negative, pale-yellow, non-spore-forming bacterium, motile with single polar flagella, strain E6T, was isolated from coastal seawater collected from Tianjin, China, and its taxonomic position was investigated using a polyphasic approach. Strain E6T requires NaCl for growth and grows optimally at pH 8.2 and 36 degrees C and in the presence of 2.0% (w/v) NaCl. It is positive for catalase and oxidase, and reduces nitrate to nitrite. The major fatty acids (>10%) are C18:1omega7c (64.71%) and 11-methyl C18:1omega7c (12.38%), the ubiquinone system is Q-10 and the DNA G+C content is 53.1 mol%. Phylogenetic analyses based on 16S rRNA gene sequences demonstrated that strain E6T represented a new lineage in the Alphaproteobacteria and is related to genera Cucumibacter, Devosia, Ochrobactrum and Ahrensia. Strain E6T shows highest 16S rRNA gene sequence similarity (93.3%) to Cucumibacter marinus CL-GR60T and less than 92.2% similarity to other relatives. It can be differentiated from its closest phylogenetic neighbours on the basis of several phenotypic features, including nitrate reduction, assimilation of D-glucose, L-arabinose, D-mannose, mannitol and maltose and major fatty acid composition. A polyphasic analysis supported the conclusion that strain E6T represents a novel genus and species of the family Hyphomicrobiaceae, for which the name Zhangella mobilis gen. nov., sp. nov. is proposed. The type strain of Zhangella mobilis is E6T (=CGMCC 1.7002T=JCM 15144T).