Abstract: Antimicrobial peptides produced by Lactococcus lactis are natural and safe. The aim of this study was to investigate the physicochemical properties of antimicrobial peptides produced by L. lactis L-H410 and optimize the fermentation conditions for its production. The antimicrobial peptides exhibited broad-spectrum activity, and was stable against a broad pH range (2.0–9.5) and thermal treatment (at 80 ℃ for 30 min) and susceptible to proteases. The fermentation conditions (temperature, initial pH, and inoculum size) and medium components (carbon sources, nitrogen sources, stimulating factors, and divalent salt ions) were optimized by the combined use of one-factor-at-a-time method, Plackett-Burman design, path of steepest ascent, Box-Behnken design, and response surface methodology. The optimum fermentation conditions that provided maximum relative antibacterial potency of 378.7 AU/mL, which was 1.2 times of that before optimization (318.4 AU/mL), were determined as 3.32%, 2.5%, 0.2%, 0.02%, 29 ℃, 6.95, and 2.5% for sucrose, peptone, polyethylene glycol (PEG) 8000, manganese sulphate concentrations (m/m), temperature, initial pH, and initial inoculum, respectively.

Key words: Lactococcus lactis L-H410; antimicrobial peptide; physicochemical properties; fermentation process optimization

摘要： 乳酸乳球菌抗菌肽具有天然、安全的特点。本研究旨在对乳酸乳球菌L-H410抗菌肽的理化性质进行研究并优化其发酵工艺。通过对乳酸乳球菌L-H410抗菌肽的抑菌谱和理化性质进行分析，发现其具有广谱抑菌性、pH值稳定性（pH 2.0～9.5）、热稳定性（80 ℃、30 min）和蛋白酶敏感性；通过单因素试验优化发酵条件（温度、初始pH值和接种量）和培养基组分（碳源、氮源、刺激因子和二价盐离子），结合Plackett-Burman试验、最陡爬坡试验和Box-Behnken响应面试验进行发酵工艺优化，确定最优发酵条件为蔗糖添加量3.32%（m/m）、蛋白胨添加量2.5%（m/m）、聚乙二醇8000添加量0.2%（m/m）、硫酸锰添加量0.02%（m/m），温度29 ℃、初始pH 6.95、初始接种量2.5%。此条件下获得抗菌肽的相对抑菌效价为378.7 AU/mL，为优化前（318.4 AU/mL）的1.2 倍。

关键词: 乳酸乳球菌L-H410；抗菌肽；理化性质；发酵工艺优化