A comparative study on the antibacterial activity of natural and biosynthesized nano bacteriocin produced from isolated lactic acid bacteria

Abstract

In Upper Egypt, The traditional dairy products are dependent on the spontaneous activity of indigenous microbial population themselves. Slightly is known about Luxor's LAB microbial population. Luxor has a hot desert climate which provides a good opportunity to focus on the endemic LAB and study their bacteriocins. On the other hand, bacteriocin application faces some restrictions such as limited antimicrobial spectrum, low yield and high dose demand. Moreover, bacteriocin nanoconjugates have recently emerged as a promising solution. Therefore, the aims of this study was to isolate and identify LAB strains from raw milk and traditional dairy products from Luxor governorate, as well as, to select the promising strains with strong antibacterial activity against some common food-associated pathogens. In addition, to use molecular techniques (PCR) for rapid screening at the species level using species-specific recA primers and distinguishing their bacteriocins encoding genes. Also, to use nanotechnology approaches to enhance the potency of extracted bacteriocin. The most significant findings of the study were as follows: A total of 23 different traditional dairy samples consist of 6 raw milk samples (cow, buffalo & goat), 8 Laban rayeb samples (cow, buffalo & goat), 1 sample of Romy cheese, 3 samples of Karish cheese, 3 samples of Mish, and 2 samples of butter collected from the surrounding regions of Luxor- Egypt. According to the isolation results, the microbial population of LAB cultivated on MRS revealed that Karish and Romy cheese had the highest