植物乳杆菌LZ222细菌素的分离纯化及其特性

Characterization and Purification of a Bacteriocin Produced by Lactobacillus plantarum LZ222

从新鲜牛奶中分离筛选出一株有抑菌活性的乳酸菌,经形态学观察、生理生化分析及16S rDNA基因序列同源性分析,鉴定该菌为植物乳杆菌,命名为LZ222。在排除有机酸、过氧化氢对该菌发酵上清液抑菌活性的干扰试验后,发现其仍有明显的抑菌活性;而将发酵上清液用蛋白酶K和胰蛋白酶处理后,其抑菌活性几乎丧失,说明该菌产生的抑菌活性物质具有蛋白质性质,初步确定是一种细菌素。理化性质分析表明:这种细菌素具有良好的热稳定性和酸碱稳定性,可被人体内蛋白酶降解。通过Tricine-SDS-PAGE蛋白电泳分析该细菌素分子质量为4.6 ku的小分子多肽。

Lactobacillin is a kind of natural biological preservative. A Lactic acid bacteria which produce antibacterial activity was isolated from fresh milk. It was identified as Lactobacillus plantarum on the base of physiological and biochemical characteristics and 16 S r DNA gene sequences, named as Lactobacillus plantarum LZ222. After eliminating some interference factors such as the organic acids, hydrogen peioxides and so on, the bacteriocin obtained from culture supernatant still remained active, and almost completely lose antimicrobial activity after treatment with trypsin, confirming it is a bacteriocin that have antibacterial activity. This bacteriocin was heat-stable and remained activity after incubation at a wide pH. It could be degraded by proteases existing in the human body. The bacteriocins partial were purified and determined that the molecular weight of the bacteriocin is approximately 4.6 ku by Tricine-SDS-PAGE.