sp. nov., an aerobic bacteriochlorophyll -containing freshwater bacterium isolated from river epilithic biofilm.

A strictly aerobic bacteriochlorophyll -containing alphaproteobacterium, designated strain S08, was isolated from a biofilm sampled at Tama River in Japan. The non-motile and rod-shaped cells formed pink-beige pigmented colonies on agar plates containing organic compounds and showed absorption maxima at 798 and 866 nm in the near-infrared region, typical for the presence of bacteriochlorophyll . The new bacterial isolate is Gram-negative, oxidase-negative and catalase-positive. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain S08 was closely related to species in the genus . The closest phylogenetic relative of strain S08 was TH-G33 (98.2 % sequence similarity). The major cellular fatty acids were C, C 2-OH and summed feature 8 (C 7/C 6). The predominant respiratory quinone was ubiquinone-9. The major polar lipids contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and an aminolipid. The G+C content of the genomic DNA was 70.6 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain S08 and the related type strains were all far lower than the cut-off value for the delineation of species. The results of polyphasic comparisons showed that strain S08 was clearly distinguishable from other members of the genus . Therefore, we propose a new species in the genus , namely, sp. nov. The type strain is S08 (=DSM 111902=NBRC 112025).