Neptuniibacter halophilus sp. nov., isolated from a salt pan, and emended description of the genus Neptuniibacter

A bacterial strain designated antisso-13(T) was isolated from a salt pan in southern Taiwan and characterized using a polyphasic taxonomic approach. Strain antisso-13(T) was gram-negative, aerobic, creamy white in colour, rod-shaped and motile by single monopolar flagellum. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain antisso-13(T) belonged to the genus Neptuniibacter and its closest neighbour was Neptuniibacter caesariensis MED92(T), with 96.7 % sequence similarity. Phylogenetic analyses based on rpoB and recA gene sequences and deduced amino acid sequences also revealed that the novel strain and N. caesariensis MED92(T) formed a distinct phylogenetic cluster. Strain antisso-13(T) exhibited optimal growth at 25-30 °C, with 2.0-4.0 % NaCl and at pH 7.0. Cellular fatty acids were C(16 : 1)ω7c (39.8 %), C(18 : 1)ω7c (29.4 %), C(16 : 0) (15.5 %), C(10 : 0) 3-OH (7.5 %), anteiso-C(11 : 0) (1.8 %), C(18 : 0) (1.8 %), C(11 : 0) 2-OH (1.6 %), iso-C(10 : 0) (1.2 %) and C(14 : 0) (1.1 %). The major respiratory quinone was ubiquinone Q-8. The polar lipid profile consisted of a mixture of phosphatidylglycerol, phosphatidylethanolamine and several uncharacterized polar lipids and the DNA G+C content was 54.2 mol%. The results of physiological and biochemical tests allowed clear phenotypic differentiation of this isolate from previously described members of the genus Neptuniibacter. It is evident from the genotypic and phenotypic data that strain antisso-13(T) should be classified as a representative of a novel species in the genus Neptuniibacter. The name proposed for this taxon is Neptuniibacter halophilus sp. nov.; the type strain is antisso-13(T) ( = LMG 25378(T) = BCRC 80079(T)). An emended description of the genus Neptuniibacter is provided.