唾液乳杆菌ZDY159a抑菌机制的研究

目的对唾液乳杆菌(Lactobacillus salivarius)ZDY159a的产酸能力和体外抑菌影响因素进行初步研究。方法采用共培养法和牛津杯法,以大肠埃希菌(Escherichia coli O157:H7)NCTC 12900和金黄色葡萄球菌(Staphylococcus aureus)CMCC 26003作为指示菌。结果唾液乳杆菌ZDY159a发酵产生的乳酸和乙酸均具有较强抑菌活性;发酵全液的抑菌活性强于发酵上清液;低p H与发酵上清液的抑菌活性呈正相关;蛋白酶和过氧化氢酶处理可降低发酵上清液的抑菌活性。结论唾液乳杆菌ZDY159a的抑菌活性与发酵过程中产生的有机酸、细菌素(蛋白或多肽类物质)和过氧化氢有关,且菌体可提高发酵上清液的抑菌活性。

Antibacterial mechanism of Lactobacillus salivarius ZDY159a

Abstract Objective To study the acid-production ability of Lactobacillus salivarius ZDY159a and factors affecting in vitro its antibacterial activity. Methods By employing co-culture and Oxford cup method, using Escherichia coli O157:H7 NCTC 12900 and Staphylococcus aureus CMCC 26003 as the indicator strains. Results Lactic acid and acetic acid produced by L. salivarius ZDY159a had strong inhibitory effects toward the indicator strains. The antibacterial activity of fermented broth (including the cells of L. salivarius ZDY159a) was higher than that of supernatant. There was a positive correlation between low pH and the antibacterial activity of supernatant. The antibacterial activity of supernatant treated with protease or catalase was decreased. Conclusion The antibacterial activity of L. salivarius ZDY159a was contributed to organic acids, bacteriocin (proteins or peptides) and hydrogen peroxide that produced by fermentation. The cells of L. salivarius ZDY159a can improve the antibacterial activity of supernatant.