Identification of Lactobacillus Species Isolated From Traditional Dairy Products Using RAPD-PCR

Background: Probiotics are non-pathogenic useful microorganisms having positive effects on the host health. The aim of the present study was to discriminate Lactobacillus species extracted from traditional dairy products. Methods: This study was conducted on ۲۶ specimens collected from traditional dairy products in Bukan. Lactobacillus species were separated and purified employing biochemical tests. Then, the intra/inter-species diversity was investigated using RAPD-PCR (random amplified polymorphic DNA-polymerase chain reaction) technique. Results: Polymorphism information content (PIC) value varied between ۱۵.۹% and ۳۴.۴% with a maximum value of ۳۴.۴% associated with primer ۱۲۵۴. The mean of and Marker index (MI) for the ۶ primers was ۴.۵۲, in which the maximum and minimum values belonged to the primers ۱۲۵۴ and OPA-۰۲, respectively. The isolates were categorized into ۴ main clusters according to Jaccard similarity coefficient using UPGMA (unweighted pair group method with arithmetic means) clustering method. Principle coordinates analysis (PCoA) demonstrated that the first and second components explained ۳۰.۵۹% and ۲۲.۴۸% of variances, i.e. ۵۳.۰۷% of variances in total. The results of RAPD marker indicated that the intra-species diversity was greater than inter-species diversity. The intra-group variance explained ۹۴% of the all variance, while inter-group variance explained only ۶% of the all variance. Moreover, the results of analysis of molecular variance (AMOVA) indicated that the highest level of discrimination occurred at the ۱۶ groups cut-off point with a similar coefficient of ۰.۵۶. Conclusions: From the results of the present study, it can be concluded that traditional dairy products are enriched sources of probiotic bacteria which can ensure the health of general population and enhance their immunoe systems. Moreover, RAPD-PCR is an appropriate method for detection and calssification of lactobassiluses.