关键词: 乳酸乳球菌, 抗菌肽, 理化性质, 发酵工艺优化

Abstract: The antimicrobial peptides produced by Lactococcus lactis are natural and safe. The aim of this study was to investigate the physicochemical properties of antimicrobial peptide produced by Lactococcus lactis L-WY410 and optimize its fermentation conditions. Through the analysis of the antibacterial spectrum and physicochemical properties of antimicrobial peptides, it was found that they have broad-spectrum antibacterial activity, acid-base stability (pH 2~9.5), thermal stability (80°C, 30min) and sensitivity to proteases; Through the manipulation of fermentation environmental conditions (including temperature, initial pH, and inoculum amount) and medium component conditions (such as carbon source, nitrogen source, stimulating factor, and divalent salt ions), a series of one-way experiments, path of steepest ascent method and Box-Behnken response surface experiments were conducted to optimize the fermentation process. The optimal fermentation conditions were finally determined to be a sucrose concentration of 3.32%, peptone concentration of 2.5%, PEG-8000 concentration of 0.2%, manganese sulphate concentration of 0.02% at a temperature of 29°C, pH of 6.95, and an initial inoculum of 2.5%. Under this condition, the relative antibacterial potency of the antimicrobial peptide obtained was 393.7AU/mL, which was 1.24 times that before optimization (318.4AU/mL). This result proves the effectiveness of the optimization of the fermentation process and provides a reference for the production of Lactococcus lactis antimicrobial peptide products and their application in the food industry.

Key words: Lactococcus lactis, antimicrobial peptide, physicochemical properties, fermentation process optimization