广谱抗菌活性瑞士乳杆菌AJT的筛选及菌种鉴定

Isolation and Identification of Broad-spectrum Antibacterial Strain of Lactobacillus helveticus AJT

从内蒙古地区传统乳制品中分离出18株乳酸菌,通过牛津杯平板扩散试验筛选具有抑制细菌和真菌生长的菌株,并通过API试剂条和16S rDNA基因序列分析鉴定菌种。筛选出一株编号为AJT的菌株,排除酸和过氧化氢干扰后,经甲醇提取的抗菌物质对革兰氏阳性和阴性细菌及真菌生长都有较强的抑制作用;其16S rDNA序列长度为1 470 bp,基因序列在GenBank的登录号为JQ775393,结合API试剂条鉴定结果,最终鉴定为瑞士乳杆菌。

We isolated 18 lactic acid bacteria from traditional fermented dairy samples in Inner Mongolia, China. The antibacterial and antifungal strain were selected by Oxford cup plate assay, and API 50CH carbohydrate fermentation test and 16S rDNA gene analysis were conducted to identify the taxonomic position of the selected strain. A strain named AJT was screened out and after eliminating the distur-bances of organic acid and H202, an antimicrobial substance was purified by methanol extraction method from the fermented supernatant of AJT grown in MRS broth, which had strong inhibitory activity to Gram-positive bacteria, Gram- negative species and fungi. Its 1 470 bp 16S rDNA sequence was deposited in GenBank under accession number JQ775393, the phylogenetic analyses based on 16S rDNA gene sequence comparison and API kit results reflected that the strain AJT was Lactobacillu~ helveticus.