A Gram-stain-negative, aerobic and curved-rod-shaped bacterium, designated QM202T, was isolated from red algae (Gracilaria blodgettii). Cells of strain QM202T were 0.2-0.3 µm wide and 1.0-2.5 µm long, catalase-negative and oxidase-positive. The strain exhibited an agar-degrading activity. It was motile by means of a single polar flagellum. Optimal growth occurred at 28-30 °C, pH 7.0-7.5 and in the presence of 2.0-3.0 % (w/v) NaCl. The DNA G+C content was 41.4 mol%. The isoprenoid quinone was identified as Q-8. Phophatidylethanolamine and phosphatidylglycerol were the predominant phospholipids. The dominant fatty acids were C18:1ω7c, C16:0 and C16:1ω7c and/or iso-C15:0 2-OH. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain QM202T belonged to the genus Marinomonas. The closest described neighbour in terms of 16S rRNA gene sequence identity was Marinomonas blandensis MED121T (95.5 %). The differential phenotypic properties, together with the phylogenetic and genetic distinctiveness indicated that strain QM202T can be considered to represent a novel species, Marinomonas agarivorans sp. nov. The type strain is QM202T (=KCTC 52475T=MCCC 1H00145T).
Keywords: Marinomonas; polyphasic taxonomy; red algae.