Extraction and Purification Nisin from Lactobacillus lactis and Determine the Optimal Conditions for its Production and Evaluation its Effectiveness in Food Preservation

Abstract The aim of the study was to purify and extract nisim from Lactobacillus lactis that diagnosed in the Laboratory of Microbiology in the Department of pathological analysis/College of Applied Sciences-Samara University. The optimal conditions for the production of nisin were determined, the optimal medium was De Man Rogosa Sharpe (MRS). As for the PH, the results showed that the best pH for the production of nisin was at pH 5, the optimum temperatures was 30° C. As for the incubation period and circumference, the highest productivity of the nisin was 18 hours. The nisin was purified using ammonium sulfate to precipitate nisin, which is one of the initial steps to purify proteins, and then the deposited protein was passed after its dilution and concentrated in the Ion Exchange column. The ability of the extracted and purified nisin in the biopreservation of meat was determined when it was added at different concentrations (25%, 50%, 100%). The concentration of 100% was the most appropriate concentration in biopreservation based on the absence of contamination in the meat during the first three days and the low numbers of bacteria from the fourth day to the seventh day, there were significant differences between the numbers of bacteria at the level of probability (P < 0.05) for samples of meat stored in refrigeration.