Malihe Hajighasemi - Department of Biology, Ashkezar Branch, Islamic Azad University, Ashkezar, Iran
Naheed Mojghani - Department, Razi vaccine and serum research institute, karaj, IR Iran

Background: Probiotic are live microbial food supplement which bestows beneficial effects on the host by creating intestinal microbial balance. In this research, we aimed to identify locally isolated LAB with probiotic potentials by phenotypic and genotypic methods. Material and methods: A number of locally isolated LAB identified by phenotypic characteristics were selected and screened for their probiotic properties. The isolates were tested for their acid and bile resistance, antibacterial activity, cholesterol reducing.  The selected probiotic LAB were identified to species level by using universal primers and ۱۶S rRNA sequencing. Results: Among the ۲۰ LAB isolates, only ۳ isolates resisted low pH value of ۲.۵, while ۵ isolates resisted ۰.۳ to ۱% bile salt. Among these ۵ isolates, ۳ isolates showed the ability to lower cholesterol significantly as they reduced ۹۴.۸, ۹۵.۷۳ and ۹۷.۸۲ % of cholesterol within ۲ hours of incubation. All isolates except for ۲۴SN hydrolyzed bile salt. Based on ۱۶S rRNA sequencing these ۵ isolates were identified as Lactobacillus plantarum (۲۲SN, ۲۴SN, NPN۰۰۲۲, ۱۰SN), and Lactobacillus rhamnosus (۳۰SN). Conclusion: The LAB isolates in this study possessed significant probiotic properties and might be used as a probiotic in human, livestock, and poultry products in the future.

Probiotic, Lactic Acid Bacteria, PCR, ۱۶SrRNA., باکتری های اسید لاکتیک, پروبیوتیک, RNA ribosomal ۱۶S, واکنش زنجیره ای پلیمراز