Afifella aestuarii sp. nov., a phototrophic bacterium

Abstract

An oval-to rod-shaped, motile, Gram-stain-negative, oxidase-positive, catalase-negative, pink-coloured phototrophic bacterium (designated as strain JA968T) was isolated from an estuary near Pata, Gujarat, India. Cells had an intracytoplasmic membrane architecture as lamellae and divided by budding. Strain JA968T had bacteriochlorophyll-a and spirilloxanthin series carot-enoids as photosynthetic pigments. The strain exhibited photolithoautotrophic, photoorganoheterotrophic and chemoorgano-heterotrophic growth modes and required thiamine as a growth factor. Strain JA968T had C18: 1 ω7c/C18: 1 ω6c as the predominant fatty acid with ubiquinone-10 (Q-10) and menaquinone-10 (MK-10) forming the quinone composition. The genomic DNA G+C content of the strain was 63.5 mol%. Pairwise comparison of 16S rRNA gene sequences showed that strain JA968T was highly similar to Afifella marina DSM 2698T (99.9 %) and Afifella pfennigii DSM 17143T (98.4 %). The average nucleotide identity values were 92 % between strain JA968T and A. marina DSM 2698T, and 78 % between strain JA968T and A. pfennigii DSM 17143T. The digital DNA–DNA hybridization values between strain JA968T and A. marina and A. pfennigii were 49 and 19 %, respectively. The genomic distinction was also supported by differences in phenotypic and chemotaxonomic characteristics. We propose that strain JA968T represents a new species of the genus Afifella with the name Afifella aestuarii sp. nov. The type strain is JA968T (=KCTC 15634T=NBRC 113338T).