传统发酵牦牛酸乳中细菌素产生菌的筛选与鉴定

Screening and identification of lactobacillin-producing strain in traditional yak yogurt

从西藏羊八井地区、云南香格里拉的传统牦牛酸乳中分离出26株乳酸菌,以枯草芽孢杆菌、大肠杆菌、金黄色葡萄球菌以及酿酒酵母为指示菌。采用牛津杯双层琼脂扩散法检测菌株的抑菌谱大小,并经过有机酸排除、过氧化氢排除、蛋白酶水解检测试验,最终筛选得到5株产细菌素的菌株,编号分别为3、23、24、21和25。通过微生物形态学与16SrDNA序列同源性分析,鉴定这些菌株分别为干酪乳杆菌、植物乳杆菌和乳酸乳球菌乳球亚种。抑菌谱试验表明,这些细菌素能够抑制部分食源性革兰氏阳性菌和阴性致病菌,对真菌无抑菌活性。

The 26 strains isolated from traditional fermented yak milk in Yangbajin-Tibet and Yunnan-Shangrila area.In this study,the inhibitory spectrum of the selected strain was determined by Oxford cup double agar diffusion method Bacillus subtilis,Escherichia coli,Staphylococcus aureus and Yeast was taken as the indicator,to screen out lactic acid bacteria with high antibacterial activity from various stains.At the same time,according to the exclusion of organic acids,hydrogen peroxide and proteolysis detection,speculated that the inhibitory effect of lactic acid bacteria may come from lactobacillin.The results showed that 3,21,23,24,25 strains have higher antibacterial activity.And 5strains were identified by 16 SrDNA sequence analysis.The 3,23 and 24as Lactobacillus casei,21 as Lactobacillus plantarum,25 as Lactococcus lactis subsp.lactis.Antibacterial spectrum test showed that lactobacillin could effectively inhibit some food-borne gram positive and negative bacteria.All isolated strains had no antimicrobial activity against fungi.