Halomarina oriensis gen. nov., sp. nov., a halophilic archaeon isolated from a seawater aquarium

Abstract

A novel halophilic archaeon, strain KeC-11(T), was isolated from a seawater aquarium at the Ocean Research Institute, University of Tokyo, Japan. The strain was aerobic, Gram-negative and chemo-organotrophic, growing optimally at 37 °C, at pH 7.0-8.0 and in 2.7 M (16 %) NaCl. The strain required at least 10 mM magnesium ions for growth. Cells of strain KeC-11(T) were non-motile and generally irregular coccoids or discoids. The DNA G+C content of the isolate was 67.7 mol%. Phylogenetic tree reconstructions indicated that it was distantly related to the other recognized members of the family Halobacteriaceae, with the closest relative being Natronomonas pharaonis Gabara(T) (91 % sequence similarity). The strain contained C(20)C(20) and C(20)C(25) diether derivatives of phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, a glycolipid chromatographically identical to the glycosyl-mannosyl-glucosyl diether (TGD-2) and at least one unidentified glycolipid. Phenotypic characterization and phylogenetic data support the placement of isolate KeC-11(T) in a novel species in a new genus within the family Halobacteriaceae, for which the name Halomarina oriensis gen. nov., sp. nov. is proposed; the type strain is KeC-11(T) ( = JCM 16495(T) = KCTC 4074(T)).