Description of Aequorivita aurantiaca sp. nov. Isolated from Coastal Sediment, and Comparative Genomic Analysis and Biogeographic Distribution of the Genus Aequorivita

A novel Gram-stain-negative, facultatively anaerobic, and non-motile bacterial strain, designated SDUM287046(T), was isolated from the coastal sediments of Jingzi Port of Weihai, China. Cells of strain SDUM287046(T) were rod-shaped with widths of 0.4–0.5 μm and lengths of 0.7–1.4 μm and could produce flexirubin-type pigments. Optimum growth of strain SDUM287046(T) occurred at 33–35 °C, pH 7.0, and with 2% (w/v) NaCl. Oxidase activity was negative, but catalase activity was positive. Phylogenetic analysis based on 16S rRNA gene sequence revealed that strain SDUM287046(T) was most closely related to Aequorivita aquimaris D-24(T) (98.3%). The main cellular fatty acids were iso-C(15:0), anteiso-C(15:0), iso-C(17:0) 3–OH, and summed feature 9 (comprised of iso-C(17:1) ω9c and/or C(16:0) 10-methyl). The sole respiratory quinone was MK-6. The polar lipids consisted of phosphatidylethanolamine (PE), one aminolipid (AL), three unidentified glycolipids (GL), and three unidentified lipids (L). The DNA G + C content was 39.3 mol%. According to the integrated results of phylogenetic, physiological, biochemical, and chemotaxonomic characteristics, we propose that strain SDUM287046(T) represents a novel species of the genus Aequorivita, for which the name Aequorivita aurantiaca sp. nov. is proposed. The type strain is SDUM287046(T) (=KCTC 92754(T) = MCCC 1H01418(T)). Comparative genomic analysis showed that the 16 Aequorivita species shared 1453 core genes and differed mainly in amino acid metabolism, cofactor metabolism, and vitamin metabolism. Biogeographic distribution analysis indicated that the marine environments were the primary habitat of Aequorivita bacteria.