Confluentimicrobium lipolyticum gen. nov., sp nov., a novel lipolytic alphaproteobacterium isolated from the junction between the ocean and a freshwater spring, and emended description of Actibacterium mucosum Lucena et al. 2012

A Gram-negative, aerobic, non-flagellated and coccoid, ovoid or rod-shaped bacterial strain, designated SSK1-4(T), was isolated from the junction between the ocean and a freshwater spring at Jeju island, South Korea. Strain SSK1-4(T) was found to grow optimally at 30 degrees C, at pH 7.0-8.0 and in the presence of 2.0 % (w/v) NaCl. In the neighbour-joining, maximum-likelihood and maximum-parsimony phylogenetic trees based on 16S rRNA gene sequences, strain SSK1-4(T) was found to form an evolutionary lineage independent of those of other genera within the family Rhodobacteraceae. Strain SSK1-4(T) exhibited the highest 16S rRNA gene sequence similarity values to the type strains of Ruegeria lacuscaerulensis (94.99 %), Ruegeria atlantica (94.98 %) and Rhodovulum marinum (94.97 %). Sequence similarities to the type strains of other recognized species were less than 94.87 %. Strain SSK1-4 T was found to contain Q-10 as the predominant ubiquinone and C-18:1 omega 7c and cyclo-C-19:0 omega 8c as the major fatty acids. The polar profile of strain SSK14(T) was found to contain phosphatidylglycerol, sulfoquinovosyldiacylglycerol, an unidentified lipid and an unidentified aminolipid as major components, which distinguish it from those of the phylogenetically related taxa. The DNAG+C content of strain SSK1-4(T) was determined to be 58.4 mol%. On the basis of the phylogenetic data and the chemotaxonomic and other phenotypic properties, strain SSK1-4(T) is considered to represent a new genus and species within the class Alphaproteobacteria, for which the name Confluentimicrobium lipolyticum gen. nov., sp. nov. is proposed. The type strain of C. lipolyticum is SSK1-4(T) (= KCTC 42136(T) = CECT 8621(T)). In addition, an emended description of Actibacterium mucosum Lucena et al. 2012 is also proposed.