Halomonas antri sp. nov., a carotenoid-producing bacterium isolated from surface seawater

Abstract

A Gram-negative, moderately halophilic bacterium, designated as strain Y3S6 T , was isolated from a surface seawater sample collected from Dongangyoeng cave, Udo-myeon, Jeju-si, Jeju-do, Repulic of Korea. Cells of strain Y3S6 T were aerobic, rod-shaped, non-sporulated, yellow, catalase- negative, oxidase-negative and motile with one polar flagellum. Growth of strain Y3S6 T occurred at 15–40 °C (optimum: 25–30 °C), at pH 6.0–9.0 (optimum: pH 7.0) and in the presence of 0–13% NaCl (optimum: 1–6 %, w/v). The novel strain was able to produce carotenoids. Its chemotaxonomic and morphological characteristics were consistent with those of members of the genus Halomonas . Phylogenetic analysis of the 16S rRNA gene sequence revealed that strain Y3S6 T formed a clade with Halomonas pellis L5 T (98.97 %) and Halomonas saliphila LCB169 T (98.90%). The average nucleotide identity and digital DNA–DNA hybridization values of strain Y3S6 T with the most closely related strains for which whole genomes are publicly available were 82.3–85.2% and 62.8–66.1 %, respectively. The major fatty acids in strain Y3S6 T were C 16 : 0 , C 19 : 0 cyclo ω8 c and summed feature 8 (composed of C 18 : 1 ω7 c and/or C 18 : 1 ω6 c ), and the predominant quinone was Q-9. Its polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, two unidentified phosphoglycolipid, one unidentified phosphoaminoglycolipid and one unidentified phospholipid. The genomic DNA G+C content based on the draft genome sequence was 64.2 mol%. The results of physiological and biochemical tests and 16S rRNA sequence analysis clearly revealed that strain Y3S6 T represents a novel species in the genus Halomonas , for which the name Halomonas antri sp. nov. has been proposed. The type strain is Y3S6 T (=KACC 21536 T =NBRC 114315=TBRC 15164 T ).

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