Isolation and Identification of Bifidobacterium animails subsp. lactis in Fermented Milk Products

Abstract:

Two strains were selectively isolated from the sample of Mengniu fermented milk product on modified MRS medium. Strain BB-12 was selectived by morphology observation, it was consistent with the characteristics of Bifidobacterium sp.. On the basis of polyphasic approach: morphology, physiology and molecular properties, it was evident that the strain BB-12 belonged to Bifidobacterium animalis subsp. lactis. Analysis of 16S rDNA sequences (GenBank accession No. GU116483) and atpD gene sequences (GenBank accession No. GU116482) revealed that the latter had clear separation of two subspecies while the former was not possible since their sequences displayed at least 99.1% homology.