为获得产抗菌肽且保鲜效果较好的乳酸菌，该研究从发酵食品中分离具有广谱抑菌活性的乳酸菌，分析其发酵上清液的主要抗菌物质成分，从热&酸碱耐受性、细胞壁完整性、细胞膜通透性及葡萄糖利用度等研究乳酸菌发酵上清液的抑菌特性；并利用单因素分析和响应面实验优化乳酸菌发酵条件，最后验证发酵上清液对猪肉和鱼肉的保鲜效果。结果表明：分别从酸豆角、发酵乳中分离得到的德式乳杆菌（Lactobacillus delbrueckii，L. delbrueckii）M2和德式乳杆菌保加利亚亚种（Lactobacillus delbrueckii subsp. Bulgaricus，L. delbrueckii subsp. bulgaricus）M6具有广谱抑菌作用，它们的抑菌成分主要为热、酸碱稳定性较好的蛋白质或肽类物质，其中，M2抑菌物质强碱耐受性优于M6。该两株乳酸菌最优发酵条件均为：接种体积分数3.00%，葡萄糖质量分数2.00 %，大豆蛋白胨质量分数3.00%，在此条件下进行验证试验，测得M2和M6的抑菌效果比优化前分别提高了25.47%和22.64%。进一步研究发现：M2、M6发酵上清液通过破坏细菌细胞壁完整性、细胞膜通透性及影响葡萄糖利用而达到抑菌作用。冷鲜肉的保鲜试验证实：M2、M6发酵上清液能减少冷鲜肉菌落总数，延长猪肉和鱼肉货架期2-4 d。研究结果将为广谱新型的生物防腐剂的开发和应用提供理论指导。

In order to obtain lactic acid bacteria, which could synthesize antimicrobial peptides and have good preservation effects, this study aimed to isolate lactic acid bacteria with broad-spectrum antibacterial activities from fermented foods, analyze the main antibacterial substances in the fermentation supernatant of lactic acid bacteria, investigate the antibacterial properties of the supernatant, including the tolerance to heat, acid, and alkali, cell wall integrity, membrane permeability and glucose availability, optimize the fermentation conditions using single factor analysis and response surface experiments, and evaluate their preservative effects on pork and fish. The results demonatreated that Lactobacillus delbrueckii M2 and Lactobacillus delbrueckii subsp. bulgaricus M6, which were isolated from sour bean and fermented milk, respectively, both exhibited good antibacterial activities with a broad spectrum. Their antimicrobial components are mainly proteins or peptides with good thermal and acid-base stability. Moreover, antimicrobial substances from M2 harbored higher tolerance to alkali than those from M6. The optimal fermentation conditions of the two strains of lactobacillus were as follows: 2% glucose and 3% soybean peptone and 3% inoculation exhibited. Under these conditions, the antibacterial effects of L. delbrueckii M2 and L. delbrueckii subsp. bulgaricus M6 were increased by 25.47% and 22.64%, respectively. Moreover, the supernatant of L. delbrueckii M2 and L. delbrueckii subsp. bulgaricus M6 could disrupt cell wall integrity and membrane permeability and impact glucose utilisation. Furthermore, the supernatant of L. delbrueckii M2 and L. delbrueckii subsp. bulgaricus M6 reduced the total viable counts and prolong the shelf-life during the storage of chilled pork and fish, extend the shelf life of pork and fish for 2-4 days. The findings will provide theoretical guidance for the development and application of new broad-spectrum biological preservatives.

广州市科技计划项目（201904010274）；广东省科技创新战略专项资金-重点领域研发计划（2020B020226008）