Screening of main microorganism from Kefir Grain and analysis of femented milk using mixed microsapsule pure cultures

Kefir grain,as a complex system of microbial symbiosis,contains many useful microorganisms. The research focused on the main microbial composition of kefir grains and the preparation of a microbial starter culture.According to the colony forms and biological properties,the kefir grain samples were consisted of two strains of yeast,three strains of lactic acid bacteria( LAB) and two strains of acetic acid bacteria( AAB). After sequencing the 16 S r DNA sequence of the seven strains,it can be concluded that the yeasts were identified as Kluyveromyces marxianus and Pichia kudriavzevii,LAB were Lactobacillus pontis and Lactobacillus kefiri,AAB were Acetobacter lovaniensis and Acetobacter cibinongensis. Further,the isolated strains were cultivated and microencapsulated.After the microcapsules were mixed and fermented in milk,the performance of the nutrition contents and volatile components and the property of antimicrobial activity were very similar to the original kefir grains.