Characterization of Marinomonas algicida sp. nov., a novel algicidal marine bacterium isolated from seawater

A novel Marinomonas-like, aerobic, Gram-reaction-negative, moderately halophilic, acidophilic, motile by a single polar flagellum, non-spore-forming, rod-shaped bacterium that showed algalytic activity, designated strain Yeongu 1-4^T, was isolated from surface seawater of Geoje Island in the South Sea, Republic of Korea. The strain was oxidase-negative and weakly positive for catalase. Growth of this bacterium was observed at temperatures from 4 to 42 °C, at salinities from 0 to 12 % and at pH from 4.5 to 9.0, and it was not able to degrade starch, gelatin, casein or Tween 80. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain Yeongu 1-4^T was related most closely to Marinomonas spartinae SMJ19^T with similarity of 99.3 %. However, levels of DNA-DNA relatedness between strain Yeongu 1-4^T and the most closely related species were lower than 70 %, confirming that they represent distinct genomic species. The genomic DNA G+C content of strain Yeongu 1-4^T was 44.2 mol%. The organism used Q-8 as the predominant respiratory quinone, and C16 : 1ω7c, C18 : 1ω7c and C16 : 0 as major cellular fatty acids. Based on data from this polyphasic taxonomic study, strain Yeongu 1-4^T belongs to a novel species of the genus Marinomonas, within the family Oceanospirillaceae, for which the name Marinomonas algicida is proposed. The type strain is Yeongu 1-4^T (=KEMB 9005-327^T=MCCC 1K00609^T).