Roseovarius nanhaiticus sp. nov., a member of the Roseobacter clade isolated from marine sediment.

An aerobic, Gram-staining-negative, rod or ovoid-shaped bacterial isolate, strain NH52J(T), was isolated from a sandy sediment sample from the South China Sea. Strain NH52J(T) exhibited tumbling motility, formed beige or faint pink colonies, gave a positive reaction in tests for catalase and oxidase and required NaCl for growth. Optimal growth was observed at pH 7.8-9.3, at 30 degrees C and in the presence of 2.0-4.0 % (w/v) NaCl. The novel strain did not synthesize bacteriochlorophyll a, and the DNA G+C content was 62 %. The major fatty acids were C(18 : 1)omega7c, C(16 : 0) and C(18 : 1)omega7c 11-methyl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain NH52J(T) was affiliated to the genus Roseovarius of the class Alphaproteobacteria. Roseovarius pacificus and Roseovarius aestuarii were the most closely related recognized species to strain NH52J(T) with 16S rRNA gene sequence similarity values of 95.0 and 95.7 %, respectively. Sequence similarity values between strain NH52J(T) and other phylogenetically related species were all below 95.0 %. Based on the phenotypic, chemotaxonomic and phylogenetic data presented, strain NH52J(T) is considered to represent a novel species of the genus Roseovarius, for which the name Roseovarius nanhaiticus sp. nov. is proposed. The type strain is NH52J(T) (=LMG 24840(T)=CCTCC AB 208317(T)=MCCC 1A03543(T)).