Journal of Microbiology

Research Support, Non-U.S. Gov't

Analyses of Bacterial Communities in Meju, a Korean Traditional Fermented Soybean Bricks, by Cultivation-Based and Pyrosequencing Methods: Yi-Seul Kim , Min-Cheol Kim , Soon-Wo Kwon , Soo-Jin Kim , In-Cheol Park , Jong-Ok Ka , Hang-Yeon Weon; J. Microbiol. 2011;49(3):340-348. Published online June 30, 2011; DOI: https://doi.org/10.1007/s12275-011-0302-3

Abstract: Despite the importance of meju as a raw material used to make Korean soy sauce (ganjang) and soybean paste (doenjang), little is known about the bacterial diversity of Korean meju. In this study, the bacterial communities in meju were examined using both culture-dependent and independent methods in order to evaluate the diversity of the bacterial population. Analyses of the 16S rRNA gene sequences of the bacterial strains isolated from meju samples showed that the dominant species were related to members of the genera Bacillus, Enterococcus, and Pediococcus. The community DNAs extracted from nine different meju samples were analyzed by barcoded pyrosequencing method targeting of the V1 to V3 hypervariable regions of the 16S rRNA gene. In total, 132,374 sequences, with an average read length of 468 bp, were assigned to several phyla, with Firmicutes (93.6%) representing the predominant phylum, followed by Proteobacteria (4.5%) and Bacteroidetes (0.8%). Other phyla accounted for less than 1% of the total bacterial sequences. Most of the Firmicutes were Bacillus and lactic acid bacteria, mainly represented by members of the genera Enterococcus, Lactococcus, and Leuconostoc, whose ratio varied among different samples. In conclusion, this study indicated that the bacterial communities in meju were very diverse and a complex microbial consortium containing various microorganisms got involved in meju fermentation than we expected before.

Journal Article

Ethanol Extract of Fermented Soybean, Chungkookjang, Inhibits the Apoptosis of Mouse Spleen, and Thymus Cells: Han Bok Kim , Hye Sung Lee , Sook Jin Kim , Hyung Jae Yoo , Jae Sung Hwang , Gang Chen , Hyun Joo Youn; J. Microbiol. 2007;45(3):256-261.; DOI: https://doi.org/2534 [pii]

Abstract: Apoptosis is a step of the cell cycle which is important in the regulation of immune cell populations. Chungkookjang is a Korean traditional fermented soybean containing microorganisms, enzymes, and bioactive compounds which was used in the treatment of mouse spleen as well as thymus cells (CH1-fermented soybean containing barley, wormwood, and sea tangle; CH2-fermented soybean) and was found to exhibit substantially reduced small DNA fragmentation. An MTT assay showed that the treatment of CH1 and CH2 into the mouse splenocytes and thymocytes sharply increased their survival. Moreover, a FACS analysis also showed that CH1 and CH2 are effective at suppressing the apoptosis of splenocytes and thymocytes. The fermented soybean isoflavone concentrations, which are implicated in lowering breast and prostate cancers, lowering the risk of cardiovascular diseases, and improving bone health, were determined using Capillary Electrophoresis-Electrochemical Detection (CE-ED). The amount of Daidzein in fermented soybean significantly increased by 44-fold dramatically, compared with those in unfermented soybean. In this study, we demonstrated that ethanol extracts of Chungkookjang promote the survival of the mouse spleen and thymus cells in culture by suppressing their apoptotic death. Future studies should investigate which genes are related to apoptosis of the immune cells.

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