屎肠球菌素E9的产生和特性研究

Study on the Properties of Enterocin E9 from Enterococcus faecium E9

关键词:  细胞连接型细菌素  屎肠球菌  Enterocin E9  抑菌活性  特性

Key words:  cell-associated bacteriocin  Entorococcus faecium  Enterocin E9  antibacterial activity  property

摘要:

用琼脂扩散法分别检测了不同培养时间的屎肠球菌E9无细胞上清液和连接在菌体上的Enterocin E9活性，同时分析了Enterocin E9的生物学特性。结果显示：含Enterocin E9的上清液和菌体都具有抑菌活性，活性大小存在浓度依赖性。在一定时间范围内，其上清液和菌体的活性都随着培养时间的增加而逐渐升高。取上清液进行稳定性分析，结果发现Enterocin E9有很好耐热和耐酸碱性，经121 ℃处理20 min后其活性仍大部分保留，在pH 2~12的范围内37 ℃下处理4 h仍保持较高活性；不同浓度的吐温-80对其活性无明显影响；室温放置7周后，活性无明显变化。上述实验说明屎肠球菌E9产生的细菌素不仅分泌到上清液中，同时还有较大部分与菌体结合。Enterocin E9稳定性良好，储藏条件简单，具有在畜牧业中应用的潜能。

Abstract:

The cell-associated Enterocin E9 activity of different cultivation time was assayed by agar diffusion method and the properties of the cell-free Enterocin E9 was analyzed .The results showed that the cell-free and cell-associated Enterocin E9 have the antibacterial activity and the activity of the Enterococcus faecium E9 cell-free supernatant was concentration-dependent. Both cell-free and cell-associated Enterocin E9 activity enhanced with the increasing cultivation time in certain time horizon. The cell-free Enterocin E9 also remained active when heated at 121 ℃for 20 min and relative high active at pH 2~12 for 4 h at 37 ℃. The cell-free activity didn’t obviously change after incubation with different concentration of Twain 80 and store at room temperature for 7 weeks. Base on these results, we can make a conclusion that Enterococcus faecium E9 released Enterocin E9 into the cell-free culture supernatant, but most of the antibacterial activity remained cell-associated. Enterocin E9 with good stability and easy to store，which will have good potential application in animal husbandry.