不同盐质量分数泡白菜发酵过程中乳酸菌群落结构的变化

设计3种不同盐质量分数的泡白菜,包括低盐(2%)、中盐(5%)、高盐(8%),利用可培养方法结合多种分子生物学手段研究其发酵过程中乳酸菌的群落结构。结果表明:盐质量分数越低,乳酸菌增长速率越快。本研究从3种不同盐质量分数泡白菜发酵过程中分离筛选得到了563株乳酸菌,并采用16S rDNA测序、多重聚合酶链式反应、聚合酶链反应-限制性片段长度多态性、API 50CH等多种不同的鉴定方法进行鉴定,鉴定结果表明这563株乳酸菌属于5个属11个种。结果表明,低盐泡白菜发酵前期的优势菌为Lactococcus lactis、Lactobacillus pentosus和Leuconostoc,发酵后期则由Lactobacillus pentosus主导;中高盐泡白菜发酵前期由Lactobacillus pentosus和Weissella主导,发酵后期主要由Lactobacillus pentosus完成。

Community Dynamics of Lactic Acid Bacteria during the Fermentation Process of Chinese Paocai with Different Salt Concentrations

The microbial community of lactic acid bacteria isolated from Chinese Paocai prepared with different salt concentrations (2%, moderate 5% and 8%), was assessed by cultivable methods and various molecular biology methods. The results showed that lactic acid bacteria in Paocai brine exhibited faster growth rate at lower salt concentration during the fermentation process. A total of 563 lactic acid bacteria were isolated from Paocai brines fermented with different salt concentrations and identified by 16S rDNA sequencing analysis, multiplex-PCR method, and PCR-FRLP analyses. The isolates were identified to belong to 11 species of 5 genera respectively. Lactococcus lactis, Lactobacillus pentosus and Leuconostoc were found to be the dominant flora in Paocai samples during the early stage of fermentation with lower salt concentration (2%) while Lactobacillus pentosus dominated the late fermentation stage. Furthermore, Lactobacillus pentosus and Weissella were the most abundant isolates from Paocai brine during the early stage of fermentation with 5% and 8% salt concentrations, but the major microbes involved in the late fermentation stage were still Lactobacillus pentosus.