Alteromonas confluentis sp. nov., isolated from the junction between the ocean and a freshwater spring

Abstract

A Gram-stain-negative, aerobic, non-spore-forming, non-flagellated and coccoid, ovoid or rod-shaped bacterial strain, DSSK2-12T, was isolated from the place where the ocean and a freshwater spring meet at Jeju island, South Korea. Strain DSSK2-12T grew optimally at 30 °C, at pH 7.0-8.0 and in the presence of 2.0 % (w/v) NaCl. Neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that strain DSSK2-12T fell within the clade comprising the type strains of Alteromonas species. Strain DSSK2-12T exhibited 16S rRNA gene sequence similarity values of 97.2-98.1 % to the type strains of Alteromonas litorea, Alteromonas marina, Alteromonas hispanica and Alteromonas genovensis and of 95.39-96.98 % to those of the other Alteromonas species. Strain DSSK2-12T contained Q-8 as the predominant ubiquinone and summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), C16:0 and C18:1 ω7c as the major fatty acids. The major polar lipids of strain DSSK2-12T were phosphatidylethanolamine, phosphatidylglycerol and one unidentified aminolipid. The DNA G+C content of strain DSSK2-12T was 48.6 mol% and its mean DNA-DNA relatedness values with the type strains of A. litorea, A. marina, A. hispanica and A. genovensis were 9-21 %. The differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strain DSSK2-12T is separated from other species of the genus Alteromonas. On the basis of the data presented, strain DSSK2-12T is considered to represent a novel species of the genus Alteromonas, for which the name Alteromonas confluentis sp. nov. is proposed. The type strain is DSSK2-12T (= KCTC 42603T = CECT 8870T).