Nibricoccus aquaticus gen. nov., sp. nov., a new genus of the family Opitutaceae isolated from hyporheic freshwater

초록

A yellow-coloured, Gram-strain-negative, non-motile, cocci-shaped, strictly aerobic bacterium, designated HZ-65(T), was isolated from hyporheic freshwater in the Republic of Korea. Strain HZ-65(T) grew at 15-37 degrees C (optimum, 25-30 degrees C), pH 5.5-9.0 (optimum, pH 7.0) and 0-0.5 % NaCl (w/v; optimum at 0 % NaCl). Phylogenetic analysis based on the 16S rRNA gene showed that strain HZ-65(T) is a member of family Opitutaceae and is closely related to Opitutus terrae PB90-1(T) (94.0% similarity), Cephaloticoccus primus CAG34(T) (93.0 %), and Cephaloticoccus capnophilus CV41(T) (92.7 %), while the similarities to other Opitutaceae-type strains were lower than 90.0 %. The DNA G+C content was 62.2 mol% and the quinone present was menaquinone-7. The predominant fatty acids were iso-C-14:0, anteiso-C-15:0, C-16:0, and iso-C-16:0, representing 70 % of the total fatty acids. The major polar lipid profile consisted of phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. Analysis of the HZ-65(T) genome revealed the presence of 300 genes that are involved in carbohydrate-active enzymes, which indicates the metabolic potential to degrade polysaccharides. The phenotypic, chemotaxonomic, genetic, and phylogenetic properties suggest that strain HZ-65(T) represents a novel species in a new genus within the family Opitutaceae, for which the name Nibricoccus aquaticus gen. nov., sp. nov., is proposed. The type strain of Nibricoccus aquaticus is HZ-65(T) (KACC 19333(T)=NBRC 112907(T)).

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