Marinobacter profundi sp. nov., a slightly halophilic bacterium isolated from a deep-sea sediment sample of the New Britain Trench

A piezotolerant, cold-adapted, slightly halophilic bacterium, designated strain PWS21(T), was isolated from a deep-sea sediment sample collected from the New Britain Trench. Cells were observed to be Gram-stain negative, rod-shaped, oxidase- and catalase-positive. Growth of the strain was observed at 4-45 degrees C (optimum 37 degrees C), at pH 5.0-9.0 (optimum 7.0) and in 0.5-20% (w/v) NaCl (optimum 3-4%). The optimum pressure for growth was 0.1MPa (megapascal) with tolerance up to 70MPa. 16S rRNA gene sequence analysis showed that strain PWS21(T) is closely related to Marinobacter guineae M3B(T) (98.4%) and Marinobacter lipolyticus SM19(T) (98.2%). Multilocus sequence analysis (MLSA) based on sequences of housekeeping genes gyrB, recA, atpD, rpoB and rpoD indicates that strain PWS21(T) represents a distinct evolutionary lineage within the genus Marinobacter. Furthermore, strain PWS21(T) showed low ANI and diDDH values to the closely related species. The principal fatty acids were identified as C-12:0, C-12:0 3-OH, C(16:1)9c, C-16:0 and C(18:1)9c. Ubiquinone-9 was identified as the major respiratory quinone. The polar lipids were identified as phosphatidylethanolamine (PE), phosphatidylglycerol (PG), diphosphatidylglycerol (DPG), aminophospholipid (APL), two unidentified lipids and an unidentified phospholipid (PL). The G+C content of the genomic DNA was determined to be 60.3mol%. On the basis of phenotypic, chemotaxonomic and molecular data, we conclude that strain PWS21(T) represents a novel species of the genus Marinobacter, for which the name Marinobacter profundi sp. nov. is proposed (type strain PWS21(T)=KCTC 52990(T)=MCCC 1K03345(T)).