A novel Gram-stain-negative, rod-shaped, aerobic, non-motile bacterial strain, designated M5A1MT, was isolated from seawater collected from the South Sea of the Republic of Korea. Based on 16S rRNA gene sequence similarity, strain M5A1MT was closely related to Mariniflexile gromovii KMM 6038T (95.3 %), Mariniflexile fucanivorans SW5T (95.2 %), Mariniflexile soesokkakense RSSK-9T (95.1 %), Yeosuana aromativorans GW1-1T (94.6 %) and Confluentibacter lentus HJM-3T (94.6 %). Genome-based phylogenetic analyses revealed that strain M5A1MT formed a distinct cluster with the type strains of the genus Mariniflexile. The major cellular fatty acid constituents (>5 % of the total fatty acids) were iso-C15:0, anteiso-C15 : 0, iso-C15 : 0 3-OH, iso-C15 : 1 G, iso-C16:03-OH and iso-C17 : 0 3-OH. The respiratory quinone was identified as MK-6. The major polar lipids were phosphatidylethanolamine and one unidentified polar lipid. The genomic DNA G+C content of strain M5A1MT was determined to be 37.7 mol%. On the basis of its phenotypic, phylogenetic and chemotaxonomic characteristics, strain M5A1MT is considered to represent a novel species within the genus Mariniflexile, for which the name Mariniflexile maritimum sp. nov. is proposed. The type strain is M5A1MT (=KCTC 72895T=JCM 33982T).
Keywords: Mariniflexile maritimum; polyphasic characterization; seawater.