应用DGGE和Real-time PCR分析酸菜发酵液中乳酸菌的动态变化

目的使用DGGE和实时荧光定量PCR分析酸菜发酵液中乳酸菌的动态改变。方法采集传统天然发酵1~8周的酸菜发酵液50mL,抽提基因组DNA,使用DGGE对乳酸菌菌群进行多样性、相似性研究和优势菌的鉴定,实时荧光定量PCR测定乳酸菌含量。结果发酵周期加长,乳酸菌的含量随之也逐渐增大。清酒乳杆菌是酸菜自然发酵过程中的优势菌型,鼠李糖乳杆菌主要存在于发酵初期,发酵的中期(3~5周)、后期(6~8周)明显减少,同时发酵后期植物乳杆菌成为优势菌并完成全部发酵过程。发酵周期延长后,香农多样性指数和丰富度较高,出现先下降后上升的趋势,在第7周达到最大值。结论在DNA水平上,DGGE和实时定量PCR检测了酸菜发酵液中乳酸菌的含量,进行菌群结构的动态分析,明确优势菌型,为实现酸菜标准化生产提供理论依据。

Dynamic changes of lactic acid bacteria in fermentation of Chinese sauerkraut by PCR-DGGE and Real-time PCR

Abstract: Objective To study the dynamic changes of lactic acid bacteria in the fermentation of Chinese sauerkraut by using Real-time PCR and DGGE. Methods Chinese sauerkraut fermentation broths which fermented for 1 to 8 weeks were collected. Quantitation analysis of lactic acid bacteria flora and analyses of diversity, similarity and sequence were carried out by using RT-PCR and DGGE respectively after DNA extraction. Results The content of lactic acid bacteria increased as the extension of fermentation. Lactobacillus sakei was the dominant bacterium. Lactobacillus rhamnosus existed in early fermentation period and reduced in later fermentation period. Lactobacillus plantarum became dominant bacterium in the later fermentation period. Shannon-Weaver indexes showed a trend of first increasing and then decreasing, which reached the maximum value at 7 weeks. Conclusion The content and dynamic changes of lactic acid bacteria were detected with DGGE and Real-time PCR at DNA level, and the dominant bacterium was verified. The result can provide the theoretical basis for Chinese sauerkraut fermentation process and standardization production.