Hasllibacter halocynthiae gen. nov., sp nov., a nutriacholic acid-producing bacterium isolated from the marine ascidian Halocynthia roretzi

Abstract

A Gram-negative, aerobic, ovoid to rod-shaped bacterial strain, KME 002(T) was isolated from a marine ascidian, Halocynthia roretzi, off the coast of Gangneung, Korea. Phylogenetic analyses based on 16S rRNA gene sequences showed that this strain belonged to the family Rhodobacteraceae in the class Alphaproteobacteria and was closely related to the type strains of Dinoroseobacter shibae, Roseovafius crassostreae and Pseudoruegeria aquimaris with 95.0, 94.7 and 94.5% 16S rRNA gene sequence similarities, respectively. KME 002(T) was an obligately halophilic bacterium requiring 1 to 5% (w/v) NaCl, with an absolute requirement for magnesium chloride for growth. Cells were motile by means of a single polar flagellum and showed budding fission. The predominant cellular fatty acid of the isolate was C-18:1 omega 7c and Q-10 was the major ubiquinone. The DNA G+C content of the strain was 71.6 mol%. The major secondary metabolites from cultures in liquid medium. were cholic acid derivatives, including 3 alpha,12 alpha-dihydroxy-7-ketocholanic acid, 12-hydroxy-3-keto-glycocholanic acid, nutriacholic acid and deoxycholic acid. These characteristics determined in this polyphasic study suggest that strain KME 002(T) represents a novel species in a new genus of the family Rhodobacteraceae. The name Hasllibacter halocynthiae gen. nov., sp. nov. is proposed for this isolate, and the type strain is KME 002(T) (=JCM 16214(T)=KCCM 90082(T)).