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 002Twas 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 familyRhodobacteraceaein the classAlphaproteobacteriaand was closely related to the type strains ofDinoroseobacter shibae,Roseovarius crassostreaeandPseudoruegeria aquimariswith 95.0, 94.7 and 94.5 % 16S rRNA gene sequence similarities, respectively. KME 002Twas 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 C18 : 1ω7cand 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 3α,12α-hydroxy-3-keto-glycocholanic acid, 12-hydroxy-3-keto-glycocholanic acid, nutriacholic acid and deoxycholic acid. These characteristics determined in this polyphasic study suggest that strain KME 002Trepresents a novel species in a new genus of the familyRhodobacteraceae. The nameHasllibacter halocynthiaegen. nov., sp. nov. is proposed for this isolate, and the type strain is KME 002T( = JCM 16214T = KCCM 90082T).