Roseovarius algicolus sp. nov., isolated from culture fluid of Cochlidinium polykrikoides.

A Gram-negative, aerobic, non-motile, catalase and oxidase positive rod-shaped bacterium, designated strain 4CoA2(T), was isolated from Cochlidinium polykrikoides culture fluid in the laboratory. The strain formed circular, glistening, grayish yellow colonies and grew at pH 7-8 and 28 °C optimally. On the basis of 16S rRNA gene sequence similarity, the strain was shown to be phylogenetically related to Roseovarius indicus B108(T) (97.6 %), Roseovarius halotolerans HJ50(T) (97.3 %), Roseovarius pacificus 2-81(T) (96.6 %), Roseovarius litoreus GSW-M15(T) (96.3 %) and Roseovarius tolerans EL-172(T) (94.27 %). Chemotaxonomic data revealed that the strain 4CoA2(T) possesses ubiquinone Q-10, and the predominant fatty acid is C18:1 ω6c or C18:1 ω7c. The polar lipids profile of the strain 4CoA2(T) included major amounts of phosphatidylglycerol, phosphatidylcholine, and diphosphatidyl glycerol. The DNA G + C content of the strain 4CoA2(T) is 62.0 %. Strain 4CoA2(T) exhibited relatively low level of DNA hybridization values (<35 %) with other Roseovarius species. On the basis of its phenotypic, genotypic properties and its phylogenetic data, strain 4CoA2(T) can be concluded to represent a novel species in the genus Roseovarius, for which the name Roseovarius algicolus sp. nov. is proposed. The type strain is 4CoA2(T) (=JCM 30823(T), =KEMB 3501-06(T)).