Marinobacter confluentis sp. Nov, a lipolytic bacterium isolated from a junction between the ocean and a freshwater lake

A Gram-stain-negative, motile, aerobic and rod-shaped bacterium, designated HJM-18^T, was isolated from the place where the ocean and a freshwater lake meet at Hwajinpo, South Korea, and subjected to a taxonomic study using a polyphasic approach. Strain HJM-18^T grew optimally at 30 °C, at pH 7.0–8.0 and in the presence of 1.0–3.0 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences showed that strain HJM-18^T belonged to the genus Marinobacter. Strain HJM-18^T exhibited 16S rRNA gene sequence similarity values of 97.05– 98.22 % to the type strains of Marinobacter algicola, Marinobacter flavimaris, Marinobacter adhaerens, Marinobacter salarius, Marinobacter salsuginis, Marinobacter guineae and Marinobacter gudaonensis and of 93.21–96.98 % to the type strains of the other species of the genus Marinobacter. Strain HJM-18^T contained Q-9 as the predominant ubiquinone and summed feature 3 (C_{16 : 1}ω7c and/or C_{16 : 1}ω6c), C_{16 : 0} and C_{18 : 1}ω9c as the major fatty acids. The major polar lipids detected in strain HJM-18^T were phosphatidylethanolamine, phosphatidylglycerol and one unidentified aminophospholipid. The DNA G+C content was 58 mol% and the mean DNA–DNA relatedness values with the type strains of the seven phylogenetically related species of the genus Marinobacter were 10–27 %. Differential phenotypic properties, together with phylogenetic and genetic distinctiveness, revealed that strain HJM-18T is separated from recognized species of the genus Marinobacter. On the basis of the data presented, strain HJM-18^T represents a novel species of the genus Marinobacter, for which the name Marinobacter confluentis sp. Nov. is proposed. The type strain is HJM-18^T (=KCTC 42705^T =NBRC 111223^T).