Polyphasic analysis in the description of Sulfitobacter salinus sp. nov., a marine alphaproteobacterium isolated from seawater

Abstract

A polyphasic analysis was performed on a novel bacterium, designated strain KMU-143T, which was isolated from seawater collected in the Republic of Korea. A novel marine bacterium KMU-143T was analyzed and described using a polyphasic taxonomic method including 16S rRNA gene sequence analysis, DNA–DNA hybridization, and physiological, biochemical, and chemotaxonomic analyses. Strain KMU-143T was Gram-stain-negative, strictly aerobic, oval-shaped, non-motile, and chemoorganoheterotrophic. Phylogenetic analysis based on the 16S rRNA gene sequence demonstrated that the novel marine bacterium belongs to the family Rhodobacteraceae, of the class Alphaproteobacteria, and that it possessed the highest (97.1%) sequence similarity with Sulfitobacter pontiacus ChLG 10T and Sulfitobacter undariae W-BA2T. DNA–DNA relatedness values between strains KMU-143T, S. pontiacus JCM 21789T, and S. undariae KCTC 42200T were less than 70%. The major isoprenoid quinone of the novel isolate was ubiquinone-10 (Q-10) and the major (> 10%) cellular fatty acids were C16:0 and C18:1 ω7c. The genomic DNA G+C content of strain KMU-143T was 56.1 mol%. The polar lipid profile of the strain KMU-143T was found to consist of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, an unidentified aminolipid, and two unidentified lipids. Based on the discriminative phylogenetic position and combination of genotypic and phenotypic properties, the strain is considered to represent a new species of the genus Sulfitobacter for which the name Sulfitobacter salinus sp. nov. is proposed. The type strain of S. salinus sp. nov. is KMU-143T (= KCCM 90322T = NBRC 113459T).