Isolation of probiotic bacteria of traditional milk in Qomprovince and investigation of their adhesion to Caco۲ cell line

Background and Aim : Probiotics are living microorganisms that has beneficial effects on thehost. Probiotics are naturally present in some foods such as dairy products and can be added toother foods. Dairy products naturally carry strains with potential probiotic properties that can beused as a valuable microbial source in the food industry and produce products with more favorablecharacteristics. Consumption of probiotics improves the health of the digestive system and helpsin regulating the microbiome, treating and reducing the symptoms of its diseases. Probiotics,especially lactobacilli, play an important role in balancing the microbiome of the digestive system.The purpose of this research was to isolate probiotic bacteria with a high ability to be used in thefood industry.Methods : In the winter of ۲۰۲۰, ۱۰۰ samples of traditional milk were prepared in the city of Qom(Iran). Samples were cultured in MRS medium after dilution, then the probiotic properties of theisolates including tolerance to bile salt and pH were investigated, and the selected isolates wereidentified morphologically, biochemical, and molecular ۱۶s rRNA gene. The amount of adhesionof the isolates to the Caco-۲ cell line as a model of epithelial cells of the digestive tract wasinvestigated, co and autoaggregation and, hydrophobicity was also evaluated for these isolates.finally, the expression of ۳ genes effective in adhesion, including mub, mapA, and ef-Tu genes,was investigated. onResults : Among the grown isolates, ۱۴ Bacillus bacteria, all of them were gram-positive and nonhemolytic,catalase, oxidase, indole, and H۲S negative, were molecularly identified, and ۵ isolateswere Lacticaseibacillus casei, Lacticaseibacillus Paracasei, Lacticaseibacillus rhamnosus,Limosilactobacillus fermentum, and Lactobacillushelveticus were identified with a similaritypercentage of ۹۸%. These ۵ isolates showed the ability to adhesion to the Caco-۲ cell line andcontained all three genes simultaneously. Finally, all isolates were registered on the NCBI website.Conclusion : The results of the present research showed that traditional milk is a very rich sourceof various probiotic bacteria, the consumption of which is beneficial for health, as well as thepossibility of further research and industrial use of isolated bacteria with the ability to adhesion tothere, are epithelium cells.

کلیدواژه ها:

probiotic ، lactobacillus ، Milk ، bacteria ، Caco-۲ cell line