Metagenomic Analysis of Microbial Changes during Dongchimi Fermentation

In this study, the microbial identification and distribution in dongchimi during fermentation and ripening were analyzed using metagenomic methods. The results revealed that among the eight samples, Rahnella perminowiae exhibited the highest average relative abundance. Notably, from fermentation days 7 to 15, the combined relative abundance of Rahnella perminowiae (36.75~61.17%) and Leuconostoc suionicum (28.96~49.27%) exceeded 86%, suggesting that these two species play pivotal roles during the later stages of fermentation. Furthermore, comparisons of the microbial community structure using PCoA and UPGMA tree analyses based on a weighted Unifrac distance matrix showed that samples from the late fermentation period (DCM_DO7, DCM_DO9, DCM_DO11, DCM_DO13, and DCM_DO15) formed a distinct cluster, while those from the early-to-mid period (DCM_DO1, DCM_DO3, and DCM_DO5) clustered separately, clearly differentiating the early/mid (days 1~5) from the late (days 7~15) stages. In addition, the top 10 most abundant bacterial species accounted for 64.96~98.56% of the entire microbial community, and network analysis based on these species identified two distinct groups with strong interspecies correlations. This study establishes a genetic basis for further research on the changes and similarities in the microbial communities across the early, mid, and late stages of dongchimi fermentation.