The Diversity Of Lactic Acid Bacteria From Traditional Chinese Pickles By PCR-DGGE Method

Pickles may origin from ancient China. This traditional food is based on natural fermentation carried out by the epiphytic lactic acid bacteria (LAB) from the vegetables that were used for raw materials of pickles. LAB plays an important role in the production of pickles. LAB can produce organic acids, bacteriocin, vitamins, and other nutrients, consume nitrite, and give a special flavor to pickles.Molecular biological methods were widely used to study the microbial diversity, and introduced into the research on food microecology in recent years. PCR-denaturing gradient gel electrophoresis (PCR-DGGE) is a very useful method, which can be combined with other technologies such as culture-dependant method, fluorescence in situ hybridization, clone and sequence. Thereby we can assess the microbial diversity more adequately. PCR-DGGE was used to analyze the biodiversity of LAB from Chinese traditional pickles in present study.Total DNA was extracted from the pickle juice by CTAB method. The V7-V8 region of 16S rDNA was amplified by PCR. DGGE bands were excised and cloned, positive clones containing 16S rDNA inserts were sequenced and blast in Genbank. Phylogenetic analyse was performed by using Phylip software package. Phylogenetic tree based on the 16S rDNA sequence displayed high identity with LAB above 98%. They are Pediococcus parvulus, Lactobacillus plantarum, Lactococcus lactis, Lactobacillus delbrueckii according to their similarities.In comparison with the results from classic microbiological methods reported, the results from DGGE were not meet completely. There were lots of factors that affect the results, such as vegetables used, seasons, regions etc. The microbial diversity of pickles by these two methods was inconsistent. It showed that both methods have its selectivity and limitation. It suggested thatwe should apply different molecular approaches and the combination of culture-dependant and culture-independent methods in the analysis of microbial diversity, so we can assess the microbial diversity more adequately and objectively.