Paracoccus beibuensis sp. nov., isolated from the South China Sea.

A Gram-negative, non-motile, short rod-shaped or spherical bacterial strain that accumulates poly-β-hydroxybutyrate (PHB) granules was isolated from the Beibu Gulf in the South China Sea. Cells have no polar or subpolar flagella, dividing by binary fission. Phylogenetic analyses based on 16S rRNA gene sequences showed that the strain formed a monophyletic branch at the periphery of the evolutionary radiation occupied by the genus Paracoccus, family Rhodobacteraceae, order Rhodobacterales, class Alphaproteobacteria. The closest neighbours were Paracoccus aestuarii strain B7(T) (97.2% similarity), Paracoccus zeaxanthinifaciens ATCC 21588(T) (97.1% similarity) and Paracoccus homiensis DD-R11(T) (96.8%). The predominant fatty acids were C(18:1) ω7c (82.1%), and significant amounts of C(18:0) (5.6%), C(10:0) 3-OH (2.3%) and C(16:0) (1.5%) were present. The predominant respiratory ubiquinone of strain JLT1284(T) was Q-10 and the DNA G+C content of strain JLT1284(T) was 67.0 mol%. The isolate was also distinguishable from members of the genus Paracoccus on the basis of phenotypic and biochemical characteristics. It is evident from the genotypic, chemotaxonomic and phenotypic data, therefore, that strain JLT1284(T) represents a novel species of the genus Paracoccus, for which the name Paracoccus beibuensis sp. nov. is proposed. The type strain is JLT1284(T)=LMG 24871(T)=CGMCC 1.7295(T)).