sp. nov., a novel bacteriochlorophyll -containing bacterium.

A strictly aerobic, bacteriochlorophyll (BChl) -containing alphaproteobacterium, designated strain K6, was isolated from seawater around an aquaculture site in the Uwa Sea in Japan. The novel strain grew optimally at 30 °C at pH 7.0-7.5 and in the presence of 2.0 % (w/v) NaCl. The nonmotile and coccoid or rod-shaped cells formed pink-pigmented colonies on agar plates containing organic compounds. Cells showed an absorption maximum at 870 nm in the near-infrared region, indicating the presence of BChl in the light-harvesting 1 complex. The new bacterial strain was Gram-stain-negative and oxidase- and catalase-positive. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain K6 was closely related to species in the genus . The closest phylogenetic relatives of strain K6 were GJSW-31 (98.56 % sequence similarity), KMM 3842 (97.63 %) and KMM 3851 (96.88 %). The G+C content of the genomic DNA was 58.26 mol%. The average nucleotide identity value of strain K6 with the type strain of was 77.16 % (SD 4.79 %). The digital DNA-DNA hybridization value of strain K6 with the type strain of was 19.40 %. The respiratory quinone was ubiquinone-10. The major cellular fatty acids were C ω7, C and 11-methyl C ω7. The dominant polar lipids were phosphatidylcholine and phosphatidylglycerol. On the basis of the genetic and phenotypic data obtained in the present study, we propose a new species in the genus : sp. nov., whose type strain is K6 (=DSM 110109=NBRC 114114). Strain K6 represents the first confirmed species that produces BChl within the genus .