optimization, partial purification, and characterization of bioactive peptides of lactobacillus paracasei isolated from traditional egyptian cheese

Background: bacteriocins are small peptides which are ribosomally synthesized and have been shown to have wide range of antimicrobial activity. the aim of this study was to optimize the production of l. paracasei mg847589 bacteriocin. furthermore, the potential antibacterial properties of the novel bacteriocins were characterized and evaluated against staphylococcus aureus. methods: the present study optimized the growth media constituents of lactobacillus paracasei mg847589 to improve bacteriocin yield by applying one-factor-at-a-time (ofat) and response surface methodology (rsm) methods. results: at ofat, two-fold activity increased against staphylococcus aureus in the presence of whey (22.5 g/l) as nitrogen source and sucrose (30 g/l) as carbon source. rsm tool was performed with media compounds using design expert 12.0.1.0. whey (22.5 g/l), sucrose (30 g/l), temperature (30 °c), and ph (6.5) condition yielded 25,600 au/ml of bacteriocin against s. aureus. bacteriocin was stable at ph range of 2.0 to 8.0 for one h and at 60 °c for 15 min. the produced antimicrobial peptide is a novel bacteriocin with molecular mass of 2,611.122 da. conclusion: bacteriocin of l. paracasei mg847589 isolated from traditional egyptian cheese (kareish) showed great antimicrobial activity and could be applied as food preservative in food manufacturing.