Asprobacter aquaticus gen. nov., sp nov., a prosthecate alphaproteobacterium isolated from fresh water

A novel Gram-negative bacterium strain, DRW22-8(T), was isolated from fresh water taken at a depth of 22 m at Daechung Reservoir, Republic of Korea. The cells of strain DRW22-8(T) were aerobic and motile with a single polar flagellum or nonmotile (stalked), and formed creamy-white colonies on R2A agar. The phylogenetic analysis based on 16S rRNA gene sequencing indicated that the strain formed a separate lineage within the order Rhodobacterales, showing similarity values under 91.8% with its closest phylogenetic neighbours, Hirschia litorea, Hirschia baltica and Hirschia maritima. The chemotaxonomic results showed Q-10 as the predominant respiratory ubiquinone, three unidentified glycolipids, an unidentified lipid and phosphatidylglycerol as the major polar lipids, and C-16 : 0, 11-methyl C-18 : 1, C-18 : 1 omega 7c and/or C-18 : 1 omega 6c as the major fatty acids. The DNA G+C content was 64.4 mol%. The combined genotypic and phenotypic data showed that strain DRW22-8(T) could be distinguished from all genera within the family Hyphomonadaceae and represented a novel genus, Asprobacter gen. nov., with the name Asprobacter aquaticus sp. nov., in the family Hyphomonadaceae. The type strain is DRW22-8(T) (=KCTC 42356(T) =JCM 30469(T)).