Bifidobacterium aquikefiri sp. nov., isolated from water kefir.

A novel Bifidobacterium, strain LMG 28769T, was isolated from a household water kefir fermentation process. Cells were Gram-stain-positive, non-motile, non-spore-forming, catalase-negative, oxidase-negative and facultatively anaerobic short rods. Analysis of its 16S rRNA gene sequence revealed Bifidobacterium crudilactis and Bifidobacterium psychraerophilum (97.4 and 97.1 % similarity towards the respective type strain sequences) as nearest phylogenetic neighbours. Its assignment to the genus Bifidobacterium was confirmed by the presence of fructose 6-phosphate phosphoketolase activity. Analysis of the hsp60 gene sequence revealed very low similarity with nucleotide sequences in the NCBI nucleotide database. The genotypic and phenotypic analyses allowed the differentiation of strain LMG 28769T from all recognized Bifidobacterium species. Strain LMG 28769T ( = CCUG 67145T = R 54638T) therefore represents a novel species, for which the name Bifidobacterium aquikefiri sp. nov. is proposed.