东北酸菜中乳酸菌的分离鉴定与耐酸性菌株的筛选

Isolation, Identi?cation and Screening of Acid Tolerant Lactic Acid Bacteria from Chinese Sauerkraut

为筛选出高耐酸性乳酸菌,通过形态学观察和随机扩增多态性DNA标记分析技术,对自然发酵酸菜中分离纯化的乳酸菌菌株进行初步鉴别,随后利用16S rDNA序列同源性分析进行种属鉴定,并筛选在pH 3.0条件下存活率较高的菌株。结果表明,72株分离乳酸菌包括62株乳杆菌和10株乳球菌,其中有21株菌的指纹图谱不相同,经鉴定,分别为乳肠球菌(Enterococcus lactis)、弯曲乳杆菌(Lactobacillus curvatus)、米曲霉乳杆菌(L. oryzae)、短乳杆菌(L. brevis)、副干酪乳杆菌(L. paracasei)、棒状乳杆菌(L. coryniformis)。pH 3.0条件下存活率在75%以上的菌株有8株,管家基因rpoA序列同源性分析结果表明高耐酸性的两株菌株为植物乳杆菌(L. plantarum),为开发功能性乳酸菌食品提供了一定理论支持。

This work was undertaken in order to obtain lactic acid bacterial(LAB) strains with high acid tolerance. LAB strains isolated and purified from naturally fermented Chinese sauerkraut were tentatively identified by morphological observation and randomly amplified polymorphic DNA(RAPD) analysis. Subsequently, 16 S rDNA sequence homology analysis was used for species identification and these strains were screened for their survival rate at pH 3.0. The results showed that a total of 72 LAB isolates were identified as Lactobacillus(62 strains) or Enterococcus(10 strains),the fingerprints of 21 of which were different. The 21 isolates were identified as E. lactis, L. curvatus, L. oryzae,L. brevis, L. paracasei or L. coryniformis. The survival rates of 8 of these strains were over 75% at pH 3.0. Homology analysis of the house-keeping gene rpoA showed that the two selected strains with high acid tolerance were L. plantarum.This study lays the foundation for developing functional foods containing lactic acid bacteria.