Characterization of Functional Microorganisms in Representative Traditional Fermented Dongcai from Different Regions of China

Abstract

Dongcai is loved for its delicious flavor and nutritional value. The microorganisms in Dongcai play a vital role in their flavor, quality, and safety, and the microbial communities of Dongcai vary greatly from region to region. However, it remains unknown what the predominant microorganisms are in different traditional Dongcai and how they affect its flavor. The objective of this study is to explore the microbial diversity of traditional fermented Dongcai in three representative Chinese regions (Tianjin, Sichuan, and Guangzhou) and further assess their microbial functions. The microbial diversity of fermented Dongcai in Guangdong has the lowest diversity compared to fermented Dongcai in Sichuan, which has the highest. The distribution of the main genera of fermented Dongcai varies from region to region, but Carnimonas, Staphylococcus, Pseudomonas, Sphingomonas, Burkholderia-Caballeronia-Paraburkholderia, and Rhodococcus are the dominant genera in common. In addition, halophilic bacteria (HAB, i.e., Halomonas Bacillus, Virgibacillus, etc.) and lactic acid bacteria (LAB, i.e., Weissella and Lactobacillus) are also highly abundant. Of these, Burkholderia-Caballeronia-Paraburkholderia, Rhodococcus, Sphingomonas, Ralstonia, and Chromohalobacter are dominant in the Sichuan samples. In the Tianjin samples, Lactobacillus, Weissella, Virgibacillus, Enterobacter, Klebsiella, and Pseudomonas are the most abundant. Predictions of microbial metabolic function reveal that carbohydrates, amino acids, polyketides, lipids, and other secondary metabolites are abundantly available for biosynthesis. In addition, the different flavors of the three types of Dongcai may be due to the fact that the abundance of HAB and LAB shows a significant positive correlation with the amounts of important metabolites (e.g., salt, acid, amino nitrogen, and sugar). These results contribute to our understanding of the link between the distinctive flavors of different types of Dongcai and the microorganisms they contain and will also provide a reference for the relationship between microbial communities and flavor substances in semi-fermented pickles.

Dynamics and correlation between volatile compounds and microbial community in chestnut rice wine fermentation

“…Burkholderia‐Caballeronia‐Paraburkholderia accounts for about 0.1% of bacteria in the 0–5 days and during the mid‐fermentation stage, its proportion increases to 0.5%, accounting for 0.37% in the finished BLMJ. Burkholderia‐Caballeronia‐Paraburkholderia are dominant bacteria in a variety of fermented foods, such as fermented Dongcai, Sufu, Doubanjiang (Yang et al ., 2021; Wu et al ., 2022; Jiang et al ., 2023). A previous study has shown that Burkholderia–Caballeronia–Paraburkholderia play an important role in the flavour formation of fermented Sufu at the early fermentation stage (Wu et al ., 2022).…”

“…The decrease of 2‐octanone in the early and middle stages of fermentation may be related to the growth and reproduction of Staphylococcus . A previous study found that Staphylococcus is one of the main microorganisms that dominate salt, acid, amino nitrogen and carbohydrate metabolism during the fermentation process of Dongcai (Jiang et al ., 2023).…”

“…The proportion of Lactococcus in the early and middle stages of BLMJ fermentation continues to increase, rising to 0.35% in the 9d and decreasing in the late stage of fermentation, accounting for 0.22% in the finished BLMJ. Lactococcus produces organic acids during its growth and metabolism, which react with alcohols in BLMJ to promote the generation of esters (Wang et al, 2023). During the fermentation process of BLMJ, the proportion of Rhodococcus is on the rise.…”