Effect of seasonal production on bacterial communities in Korean industrial kimchi fermentation

Kimchi is prepared by fermenting salted vegetables with various ingredients and lactic acid bacteria, which are essential for the process. The aim of this study was to expiscate phylogenetic associations with the season and salinity of manufactured kimchi with respect to bacterial-community composition. We analyzed 66 Chinese cabbage kimchi samples obtained in the spring, autumn, or winter from commercial sources in six Korean provinces (Gangwon, Gyeonggi, Chungcheong, Gyeongsang, Jeolla, and Jeju) by Illumina MiSeq sequencing. The pH and salinity of the kimchi samples ranged from 5.02 to 6.13 and 1.40%-3.30%, respectively, and the salinity differed significantly by season and influenced bacterial-diversity indexes. Variations in operational taxonomic units and the Shannon index correlated significantly with salinity and seasonality. Moreover, microbial-community differences were strongly reflected in the seasonality of kimchi samples in non-metric multidimensional scaling plots and by analysis of similarity. Additionally, the distribution patterns of Leuconostoc, Lactobacillus, and Weissella spp. were well predicted by seasonality, demonstrating the importance of comprehensive correlations in bacterial community on variable environmental factors. Understanding key processes that control microbial distributions during kimchi fermentation offer insight into the biological variations of this food and the relationship between various kimchi properties and its microbiota.