Investigation on microbial diversity of industrial Zhacai paocai during fermentation using high-throughput sequencing and their functional characterization

The microbial diversity and functions during the fermentation of industrial Zhaicai paocai, a traditional fermented vegetable, was characterized by high-throughput sequencing. Results showed that Lactobacillus grew fast at the beginning, and then reached a stable level at the later fermentation stage. Population of Vibrio, Halomonas, Leuconostoc and Weissella decreased while that of Pediococcus increased throughout the fermentation. Leuconostoc and Weissella were the main lactic acid bacteria (LAB) in the initial fermentation stage, while Lactobacillus was dominant in the middle fermentation stage, and Lactobacillus and Pediococcus dominated the later fermentation stage. Debaryomyces was the dominant fungus in industrial Zhaicai paocai. Most of genes were classified as metabolism genes, in which carbohydrate metabolism (CM) genes had the highest abundance. Among CM pathways, genes for glycolysis/gluconeogenesis (CM1), pyruvate metabolism (CM2) and fructose and mannose metabolism (CM4) were detected with high abundance, which were all related to the production of lactic acid. Genes involved in the pathways of CM1, CM2 and CM4 were affiliated with Lactobacillus and Pediococcus, such as P. edianolidurans, P. parvulus, L. plantanun, P. damnosus, L. paralimentartus etc. This findings advanced our understanding of microbial metabolic modes during paocai fermentation, and it may lead to improvement of the palatability of paocai.