Maribacter aquimaris sp. nov., isolated from seawater adjacent to Fildes Peninsula, Antarctica.

A novel Gram-stain-negative, aerobic, and rod-shaped bacterium with gliding motility, named strain ANRC-HE7, was isolated from the seawater of Biological Bay adjacent to Fildes Peninsula, Antarctica. The optimal growth of this strain occurred at 28 °C, pH 7.5, and in the presence of 1.0% (w/v) NaCl. Strain ANRC-HE7 can produce amylase and harbors gene clusters involved in cellulose degradation. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain ANRC-HE7 formed a distinct lineage within the genus Maribacter and was closely related to Maribacter luteus RZ05 (98.4% sequence similarity), Maribacter polysiphoniae LMG 23671 (98.3%), and Maribacter arenosus CAU 1321 (97.3%). However, digital DNA-DNA hybridization and average nucleotide identity values between strain ANRC-HE7 and closely related strains were 17.4-49.1% and 70.9-92.7%, much lower than the cutoff values of 70% and 95%, respectively. On the other hand, strain ANRC-HE7 shared characteristics with most type strains within the genus. Its respiratory quinone was MK-6. The major fatty acids were iso-C, summed feature 3 (C ω7c and/or C ω6c), and anteiso-C. The major polar lipids were phosphatidylethanolamine, two unidentified aminolipids, four unidentified phospholipids, and five unidentified glycolipids. The DNA G + C content of strain ANRC-HE7 was 40.1%. Based on the results of the biochemical, phylogenetic, and chemotaxonomic analyses, strain ANRC-HE7 is suggested to represent a novel species of the genus Maribacter, for which the name Maribacter aquimaris sp. nov. is proposed. The type strain is ANRC-HE7 (= MCCC 1K03787 = KCTC 72532).