(浙江工商大学食品与生物工程学院 浙江省食品微生物技术研究重点实验室 杭州 310018)
(College of Food Science and Biotechnology， Zhejiang Gongshang University， Key Laboratory for Food Microbial Technology of Zhejiang Province， Hangzhou 310018)
从西藏干酪中分离筛选出1株能够产生抑菌活性物质的乳酸菌，该菌的发酵上清液在排除有机酸、过氧化氢的影响后仍有显著抑菌活性，然而，用胃蛋白酶、蛋白酶K和胰蛋白酶处理后抑菌活性丧失，说明该菌的代谢产物中起抑菌作用的物质具有蛋白质性质，初步确定是一种细菌素。结合形态学观察、生理生化分析及16S rDNA鉴定结果，确定该菌为植物乳杆菌，命名为ZFM804。细菌素经大孔树脂(XAD-16)层析、强阳离子交换层析、RP-HPLC三步法初步纯化。经SDS-PAGE分析该细菌素分子质量约为15 ku。理化性质分析表明该细菌素具有良好的酸碱稳定性:在pH 3~11范围内都具有抑菌活性；良好的热稳定性:100 ℃处理30 min仍有明显抑菌活性，同时可被人体内蛋白酶降解。抑菌谱测定结果表明，ZFM804植物乳杆菌素对革兰氏阳性菌和革兰氏阴性菌都有抑制作用，是一种广谱细菌素。
A strain of lactic acid bacteria which produce antibacterial active substances was isolated and sifted from Tibetan cheese. After eliminating the interference of organic acids and hydrogen peroxide， the fermentation supernatant of the bacteria still had obvious antibacterial activity. After the fermentation supernatant was treated with pepsin， proteinase K and trypsin， its antibacterial activity was lost， indicating that the antibacterial substance in the metabolite of the bacteria had protein properties， and it was preliminarily determined to be a bacteriocin. It was identified as Lactobacillus plantarum by morphological observation， physiological and biochemical analysis and homology analysis of 16S rDNA gene sequence， named Lactobacillus plantarum ZFM804. The bacteriocin was preliminarily purified by macroporous resin (XAD-16) chromatography， strong cation exchange chromatography and RP-HPLC three-step method. The molecular mass of the bacteriocin was determined 15 ku approximately by SDS-PAGE. The analysis of physical and chemical properties showed that the bacteriocin had good acid-base stability: had bacteriostatic activity in the range of pH 3~11； good thermal stability: 100 ℃ treatment for 30 min still had obvious bacteriostatic activity， and could be degraded by proteases in human body. The results of the antibacterial spectrum assay showed that the bacteriocin had inhibitory effects on both gram-positive and gram-negative bacteria， and was a broad-spectrum bacteriocin.