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Title: IDENTIFICATIONS OF PREDOMINANT BACTERIAL ISOLATES FROM THE FERMENTING KIMCHI USING ITS-PCR AND PARTIAL 16S RDNA SEQUENCE ANALYSES

Author
item CHIN, HWA - YONSEI UNIV., S. KOREA
item Breidt, Frederick
item FLEMING, HENRY - RETIRED USDA/COLLAB.
item SHIN, WON-CHEOL - KANGWON UNIV., S. KOREA
item YOON, SUNG-SIK - IFBB, S. KOREA

Submitted to: Journal of Microbiology and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/30/2005
Publication Date: 3/1/2006
Citation: Chin, H.S., Breidt, F., Fleming, H.P., Shin, W., Yoon, S. 2006. Identifications of predominant bacterial isolates from the fermenting kimchi using ITS-PCR and partial 16S rDNA sequence analyses. Journal of Microbiology and Biotechnology. 16:68-76.

Interpretive Summary: This manuscript describes the use of molecular ecology techniques to examine the bacteria present in the Korean fermented cabbage product kimchi. Using DNA sequencing methods, several bacterial species not previously found in kimchi were characterized, including bacteria that had not previously been identified by DNA sequencing methods. The bacteria were also biochemically characterized to determine basic traits, such as sugar fermentation patterns. A rapid DNA fingerprinting method was carried out, so bacterial isolates from vegetable fermentations could be easily distinguished in future studies. This work advances the understanding of the bacterial interactions that occur in food fermentations.

Technical Abstract: Despites many attempts to explore the microbial diversity in kimchi fermentation, the predominant flora remains controversial to date. In the present study, major lactic acid bacteria (LAB) were investigated in Chinese cabbage kimchi in the early phase of fermentation. For the samples over pH 4.0, viable cell counts of Leuconostic and Pediococcus were 10 super6 cfu/ml and below 10 super2 cfu/ml, respectively, and 20 isolates out of 172 were subjected to a biochemical identification (API 59 CH kit) as well as molecular-typing methods including ITS-PCR with a RsaI digestion and 16s rRNA gene sequence analysis for species confirmation. Seven isolates were nicely assigned to Lb. brevis, 6 to Leuconostoc spp. (2 mesenteroides, 2 citreum, 1 carnosum, 1 gasicomitatum), 4 to Weissella (3 kimchii/cibaria, 1 hanii) and 2 to other Lactobacillus spp. (1 farciminis, 1 plantarum). On the other hand, the biochemical identification data revealed 9 strains of Lb. brevis, 6 strains of Leuconostocs, 2 strains of Lb. plantarum and 1 strain each of Lb. coprophilus and Lactococcus lactis. However, a single isolate, YSM 16, was not matched to the ITS-PCR database constructed in the present study. Two Lb. brevis strains by API 50 CH kit were reassigned to W. kimchii/cibaria, Lb. coprophilus or W. hanii, respectively, judging from the results by the above molecular typing approaches. As a whole, the identification data obtained by the biochemical test were different from those of ITS-PCR molecular method by about 63% at genus-level and 42% at species-level. The data by the ITS-PCR method conclusively suggest that predominant LAB species is probably heterolactic Lb. brevis, followed by W. kimchii/cibaria, Leuc. mesenteroides, and Leuc. citreum, in contrast to the previous reports {3} that Leuc. mesenteroides is the only predominant species in the early phase kimchi fermentation.