Roseigium denhamense gen. nov., sp. nov. and Roseibium hemelinense sp. nov., aerobic bacteriochlorophyll-containing bacteria isolated from the east and west coasts of Australia.

Phenotypic and phylogenetic studies were performed with 10 strains of bacteriochlorophyll-containing bacteria isolated from a variety of marine environments (surface of Rhodophyta, sand and algal sand mat) on the east and west coasts of Australia. The strains were aerobic, chemoheterotrophic, Gram-negative, motile rods with peritrichous flagella. Bacteriochlorophyll a was synthesized under aerobic conditions. Catalase, nitrate reductase, oxidase and phosphatase were produced. ONPG reaction was positive. The strains have been divided into genotype group 1 (seven strains) and genotype group 2 (three strains) according to previously described DNA-DNA hybridization data. Strains OCh 254T and OCh 368T have been included in genotype groups 1 and 2, respectively. The results of 165 rRNA gene sequence comparisons revealed that strains OCh 254T and OCh 368T formed a new cluster within the alpha-2 group of the alpha subclass of the Proteobacteria. The similarity value of the 16S rRNA gene sequences between strain OCh 254T and the most closely related species, Stappia aggregata, was 95.6 %. The sequence similarity value between strains OCh 254T and OCh 368T was 97.1%. It was concluded that these two strains should be placed into a new genus, Roseibium gen. nov., as Roseibium denhamense sp. nov. and Roseibium hamelinense sp. nov. The type species of the genus is Roseibium denhamense. The type strains of Roseibium denhamense and Roseibium hamelinense are OCh 254T (= JCM 10543T) and OCh 368T (= JCM 10544T), respectively.