【作者】 李丽杰；

【导师】 贺银凤；

【作者基本信息】 内蒙古农业大学 ， 农产品加工及贮藏工程， 2004， 硕士

【摘要】 本文研究了分离自牧民家庭的15个酸马奶酒样品中的19株酵母菌，归为8个属，主要进行了抑菌特性的研究。结果表明，产抑菌活性物质的酵母菌5株，表现抑菌活性部分均为发酵液，菌泥部分未表现抑菌活性。这5株菌对大肠埃希氏菌都有抑菌作用，其中有3株菌还同时对金黄色葡萄球菌有抑菌作用，但抑制作用不如对大肠埃希氏菌强烈。其中2株为酒香酵母属，1株为厚壁孢酵母属。从中选择了抑菌活性较稳定、抑菌范围较广而且抑菌活性较大的5号酒香酵母菌，对其抑菌活性物质产生条件、抑菌物质粗提、以及粗提物理化特性进行了研究。结果表明选用葡萄糖—酵母膏—蛋白胨培养基、培养温度26～28℃、pH值范围为5.0～6.0, 可使抑菌物质的抑菌活性最高。该抑菌物质生成的最高值是该菌株生长的稳定期的后期，即54h后。用乙醚作萃取剂，并且在pH值2和8下萃取效果最好，抑菌活性最大。此抑菌物质不属于标准六大类抗生素，是中性物质，并且是一种混合物，含有四种成分，推测其中三种是蛋白质，其分子量分别在16,300、22,100和25,900左右。另一种是小分子物质，小分子物质的抑菌活性与三种蛋白质相比略强，而三个蛋白质的抑菌活性差别不大。不同温度、pH值均对抑菌物质的活性有很显著的影响。同一温度下pH值越高，抑菌活性越低，而同一pH值下，温度越高，抑菌活性越低。这种物质在酸性条件下具有很强的热稳定性，对胃蛋白酶和胰蛋白酶不敏感，耐受性强。更多还原

【Abstract】 The antibacterial characteristics of nineteen strains of Yeasts isolated from fifteen samples of koumiss collected from heardman,s house in Inner Mongolia were studied. The supernatants of five strains of Yeasts were shown to inhibit Escherichia coli growth.. Among them, there were also three strains could shown antibacterial property on Staphylococcus aureus, but as not strong as inhibiting property on Ecoli. Two strains of Brettanomyces, and one strain of Pachytichospora were identified from the five strains. One strain of Brettanomyces with higher inhibiting activity on bacteria was chosen for further study. The optimum antibacterial activity was obtained under the culture of glucose―yeast extract―peptone, culturing temperature of 27℃ and pH ranging 5.0~6.0. The antibacteria substance extracted by ethyl ether at pH value of 2 and 8 showed the greatest activity in the study. The antibiotic substance with a nature of neutral is not belongling to the Six Standard Antibiotics. The antibacteria substance composed with three kinds of proteins with molecule weight of 16300, 22100 , 25900 and one kind of small molecule substance. The small molecule substance showed stronger inhibiting activity on bacteria than the proteins. There were no significant differences of nature of antibacteria among the proteins. The results indicated that the antibacteria activity of antibacteria substance was affected significantly by temperature and pH value. As pH increasing, the higher temperature, the more the losses of antibacteria activity and the sunstance behaved insensitive to trypsin and pepsin.更多还原