产细菌素米氏链球菌S_3的筛选及其细菌素生物学特征研究

Screening of Bacteriocin-producing Streptococcus Milleri S3 Strain and Studying On Biological Characteristics of Bacteriocin

从大连地区泡菜中分离到32株乳酸细菌,通过牛津杯法,从中筛选出1株有明显抑菌活性代谢产物的米氏链球菌S3。排除酸、过氧化氢等干扰因素后,离心发酵液对指示菌Micrococcus flavs ATCC28001仍有抑菌作用,用胰蛋白酶对其透析液处理后活性丧失,说明它们产生的抑菌物质是细菌素。以S3菌株为试材,对其细菌素类物质的产生及细菌素粗提物进一步研究,发现在对数末期其抑菌活性最高, 对热相对稳定(100℃ 20 min),易被胰蛋白酶、蛋白酶K和胃蛋白酶失活,显示活性的pH值范围为4.0～5.5,粗提液表现为不仅抗藤黄微球菌属、枯草芽孢杆菌属、金黄色葡萄球菌属等革兰氏阳性菌,而且对大肠杆菌(E. coli)等革兰氏阴性菌也有一定抑制作用。说明S3菌株产生的是一类具有广谱抗菌作用的细菌素。

lactic acid bacteria strains had been separted from cabbage pickles.Among them,one streptococcus milleri S3 strains was screened out whose metabolized products are provided with inhibitive activity to other strains through cylinder plate assay.After overcoming disturbed factors from organic acid and hydrogen peroxid,the supernatants of fermented centrifugal liquor shows inhibitory effect to Micrococcus flave ATCC28001,an indicator strain.But its activity lost after its thoroughly resolved liquor treated by trypsinogen.There fore,the producted inhibitory substance can be classed as bacteriocin.We take S3 strain as sample for further research.Maximum production of the inhibitory compound is obtained in the later logarithmic period.The inhibitory compound shows heat stable(20min at 100℃),active in PH 4.0～4.5,but sensitive to several proteases,including trypsinogen,protease K and pepsin.The crude extract of S3 strain shows not only inhibitive to some gram-positive bacteria,such as escherichia,colibacillus,subtili- cin,staphylococcus aureus,but also inhibitive activity to gram-negative bacteria,such as E colibacillus.