Deefgea rivuli gen. nov., sp. nov., a member of the class Betaproteobacteria

Two strains, designated WB 3.4-79(T) and WB 3.3-25, were isolated from a hard-water sample collected from the Westerhöfer Bach, Lower Saxony, Germany. The strains shared 100 % DNA-DNA relatedness, indicating membership of the same genospecies. This close relationship was supported by identical 16S rRNA gene sequences and high similarities in fatty acid composition and biochemical characteristics. The G+C content of the genomic DNA of strain WB 3.4-79(T) was 48.5 mol% and the predominant ubiquinone was Q-8. Major polar lipids were phosphatidylethanolamine and phosphatidylglycerol. Major fatty acids (>10 %) were C(16 : 0) and C(16 : 1)omega7c. Polyhydroxybutyrate and polyphosphate granules as well as unidentified enterosomes and a polar organelle are visible by electron microscopy. Comparative 16S rRNA gene sequence analysis indicated that the isolates were placed within the class Betaproteobacteria, remotely related to Chitinibacter tainanensis DSM 15459(T), Silvimonas terrae KCTC 12358(T), Formivibrio citricus DSM 6150(T) and Iodobacter fluviatilis DSM 3764(T). On the basis of phylogenetic and phenotypic distinctness, we propose a novel genus, Deefgea gen. nov., with Deefgea rivuli sp. nov. as the type species. The type strain of Deefgea rivuli is strain WB 3.4-79(T) (=DSM 18356(T)=CIP 109326(T)).