Microbial population dynamics of kimchi, a fermented cabbage product

Lactic acid bacteria are known to perform significant roles in the fermentation of kimchi, a fermented cabbage product. However, the microbial population dynamics inherent to kimchi fermentation remain to be clearly elucidated. In this study, we have characterized the microbial dynamics via the identification of a total of 970 bacterial isolates, representing 15 species of the genera Lactobacillus, Leuconostoc, and Weissella, all of which were primarily identified by PCR-based restriction enzyme analysis. These population dynamics appear to be influenced markedly by fermentation temperature. Distinct biphasic microbial growth was observed with preliminary 2-day incubation at 15 degrees C, conducted before main fermentation at -1 degrees C. Leuconostoc citreum, as well as Leuconostoc gasicomitatum, predominated during the first growth phase, whereas Weissella koreensis predominated during the second phase. By way of contrast, with preliminary 4-day incubation at 10 degrees C, only W. koreensis grew rapidly from the beginning of the process. Therefore, our findings suggest that a short incubation at 15 degrees C enhances the growth of the less psychrophilic Leuconostoc species, including Lc. citreum, thus delaying the growth of the predominant W. koreensis, which is a more adaptive species at -1 degrees C.