• 생명과학회지
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• 제33권4호
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• pp.325-333
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• 2023

본 연구에서는 김치와 묵은지의 미생물 군집 구조와 이화학적 특성을 비교 분석하였다. 김치와 묵은지의 이화학적 특성 분석 결과 묵은지 시료들의 pH가 김치보다 더 낮았으며, 산도는 더 높은 것으로 나타났다. 김치와 묵은지 간의 염도에는 차이가 없는 것으로 나타났으며, 김치에서 당도가 묵은지보다 높은 것으로 나타났다. α-diversity 분석 결과 김치와 묵은지 사이에 종 추정치와 종 풍부도 지수는 차이가 없는 것으로 나타났으나, 계통발생학적 차이를 반영한 phylogenetic diversity 지수는 묵은지에서 김치보다 유의한 수준으로 높은 것으로 나타났다. 김치와 묵은지의 미생물 군집을 생물학적 분류수준에 따라 분석한 결과 두 그룹 모두 공통적으로 과(family) 수준에서 Lactobacillaceae가 가장 우점하였으나, 높은 내산성을 갖거나 김치 내에서 높은 성장 경쟁력을 갖는 것으로 알려진 Pediococcus 속과 Lactobacillus 속 유산균의 상대적인 분포가 묵은지에서 높은 것으로 나타났다. 김치와 묵은지의 전체 미생물 군집 구조에 통계학적으로 차이가 있는지 분석하기 위해 beta set-significance 분석을 수행한 결과 김치와 묵은지 두 그룹의 전체 미생물 군집구조가 통계학적으로 신뢰수준에서 매우 다른 것으로 나타났으며, 김치에서 상대적으로 높은 Weissella kandleri의 분포와 묵은지에서 상대적으로 높은 Pediococcus inopinatus의 높은 분포가 김치와 묵은지의 전체 미생물 군집 구조 차이에 가장 큰 영향을 미치는 것으로 나타났다.

• 생명과학회지
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• 제34권7호
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• pp.453-464
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• 2024

간장의 발효는 원재료인 메주와 천일염에서 천이된 미생물 군집에 큰 영향을 받는 것으로 알려져 있다. 본 연구에서는 간장의 발효 고도화를 위하여 메주의 크기 변화가 간장의 미생물 군집에서 분포 변화와 분포 상관관계에 대하여 미치는 영향을 조사하였다. 메주를 전체, 삼등분하여 간장을 제조하였으며, 28일간 발효를 진행하면서 7일 간격으로 간장 시료를 수집하여 16S rRNA 유전자 기반의 미생물 군집 분석을 진행하였다. 속 수준에서 발효가 진행되면서 메주를 전체 사용하여 제조한 간장은 Chromohalobacter (7일), Pediococcus (14일), Bacillus (21일), Pediococcus (28일) 순으로, 메주를 삼등분하여 제조한 간장은 28일 연속으로 Pediococcus가 가장 우점하였다. 메주 크기를 달리한 간장들의 미생물 군집의 beta-diversity 분석 결과, 발효 7일 차와 14일 차에서 메주 크기를 달리하여 제조한 간장의 미생물 군집 분리가 유의미한 차이를 가진다고 보여주었으나 발효 21일 차와 28일 차에는 모든 실험구의 미생물 군집은 분리되지 않았다. 미생물 군집의 분리가 시각적으로 나타난 발효 7일 차와 14일 차에서 미생물 군집 차이를 부여하는 바이오마커를 조사하기 위해 선형 판별 효과 크기 분석을 수행하여 LDA size 별로 정렬하였으며, 발효 7일차에서는 Gammaproteobacteria, Firmicutes, Oceanospirillales, Halomonadaceae, Bacilli, Chromohalobacter 순으로 호염성 미생물군이, 발효 14일 차에서는 Pedioccoccus acidilactici, Lactobacillaceae, Pediococcus, Bacilli, Leuconostocaceae, Weissella 순으로 유산균군이 미생물 군집 차이를 나타내는 것으로 조사되었다. 또한 속과 종에 속하는 바이오마커 미생물군을 주요 미생물로 간주하여 상관관계를 분석한 결과, 메주 크기 별로 미생물군집 간 상관관계가 차이가 있으며, 이에 따라 메주 크기가 간장 내 미생물 간 상호작용에 영향을 미칠 수 있는 것을 확인하였다.

• 한국식품영양학회지
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• 제30권2호
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• pp.191-202
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• 2017

This study was conducted to investigate the characteristics of major prebiotics and the related studies, and to provide basic data for future research. Prebiotics are defined as 'nondigestible food ingredients that beneficially affect the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon, and thus improve host health'. Well-known prebiotics are inulin, oligofructose, and galacto-oligosaccharide. Prebiotics assist in the health activity of lactic acid bacteria by acting as a substrate for lactic acid bacteria, with their unique physical and chemical properties. Bifidobacteria are known to be beneficial bacteria that prevent intestinal inflammation, maintain intestinal microflora balance, inhibit carcinogenesis, reduce cholesterol, and enhance immunity. However, Bifidobacteria, Lactobacillus, Bacillus, and Weissella are also found in animal-based fermented foods such as milk, cheese, yogurt, and salted fish. Prebiotics can act as a substrate for lactic acid bacteria, helping the activity of lactic acid bacteria and improving health. Therefore, the authors suggest that investigation into the category and effectiveness of prebiotics should be extended in the future through research.

• Journal of Microbiology and Biotechnology
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• 제30권4호
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• pp.599-603
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• 2020

In the present study, we examined the effects of interleukin (IL)-10 expression-inducing bacteria Bifidobacterium adolescentis HP1, Lactobacillus mucosae HP2, and Weissella cibaria HP3 on high-fat diet (HFD)-induced obesity and liver steatosis in mice. Oral gavage of HP1, HP2, and HP3 reduced HFD-induced bodyweight gain, triglycerides, and total cholesterol levels in the blood and liver. They also suppressed HFD-induced colitis and the fecal δ,γ-Proteobacteria population. Of the tested bacteria, HP2, which most potently inhibited IL-10 expression, also suppressed HFD-induced bodyweight gain, liver steatosis, and colitis most effectively. These findings suggest that IL-10 expression-inducing gut bacteria can suppress obesity and liver steatosis.

• 한국식생활문화학회지
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• 제34권2호
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• pp.142-158
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• 2019

Kimchi is a traditional Korean fermented vegetable probiotic food. The use of high quality ingredients and predominant LAB (lactic acid bacteria)-whether it be ambient bacteria or adding starters, low temperature and facultative anaerobic condition for the fermentation are important factors for preparing kimchi with better taste and functionality. The predominated LAB genera are Leuconostoc, Lactobacillus, and Weissella in kimchi fermentation. The representative species are Leu. mesenteroides, Leu. citrium, Lab. plantarum, Lab. sakei, and Wei. koreensis. Kimchi, especially the optimally fermented kimchi, has various health benefits, including control of colon health, antioxidation, antiaging effects, cancer preventive effect, antiobesity, control of dyslipidemic and metabolic syndrome, etc.; due to the presence of LAB, various nutraceuticals, and metabolites from the ingredients and LAB. The kimchi LAB are good probiotics, exhibiting antimicrobial activity, antioxidant, antimutagenic and anticancer effects, as well as immunomodualatory effect, antiobesity, and cholesterol and lipid lowering effects. Thus, kimchi ingredients, LAB, fermentation methods, and metabolites are important factors that modulate various functionalities. In this review, we introduced recent information showing kimchi and its health benefits in Korean Functional Foods (Park & Ju 2018).

• Journal of Microbiology and Biotechnology
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• 제32권3호
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• pp.341-347
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• 2022

In this study, the bacterial community of galchi-baechu kimchi was determined using culture-based and culture-independent techniques (next generation sequencing:NGS), and showed discrepancies between results. Weissella koreensis and Pediococcus inopinatus were the dominant species according to the NGS results, while Bacillus species and P. inopinatus were dominant in the culture-dependent analysis. To identify safe starter candidates, sixty-five Bacillus strains isolated from galchi-baechu kimchi using culture-dependent methods were evaluated for their antibiotic resistance, presence of toxin genes, and hemolytic activity. Strains were then assessed for salt tolerance and protease and lipase activity. As a result, four strains-B. safensis GN5_10, B. subtilis GN5_19, B. velezensis GN5_25, and B. velezensis GT8-were selected as safe starter candidates for use in fermented foods.

• Asian-Australasian Journal of Animal Sciences
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• 제31권3호
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• pp.429-438
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• 2018

Objective: Although the efficacy of Rubus coreanus (RC) byproducts as a feed additive has been recognized, its effects on intestinal microorganisms and the immune system are still unknown. Methods: Six-week-old male rats were treated with 0.5% RC (T1), 1.0% RC (T2), and 1.5% RC (T3) for 4 weeks. Results: We found that treatment with RC byproducts significantly increased the daily gain of body weight and feed intake. Treg-cell differentiation was enhanced in the mesenteric lymph nodes and spleen from the rats fed with RC byproducts. Illumina sequencing showed that bacteria in the phylum Firmicutes decreased and while those in the phylum Bacteroidetes increased in RC-treated groups. Particularly, the pathogenic microorganisms in the family Peptococcaceae decreased, and the non-pathogenic families Lachnospiraceae and S24-7 increased. Quantitative polymerase chain reaction analysis showed that the RC byproducts increased the lactic acid bacteria Bifidobacterium spp., Oscillospira spp., Leuconostoc citreum, and Weissella cibaria in a concentration-dependent manner. Conclusion: RC byproducts may be effective in immunomodulation by affecting intestinal microorganisms.

• 한국식품과학회지
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• 제50권4호
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• pp.400-406
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• 2018

본 연구는 국내 수도권, 충청, 강원 등지의 중소기업형 소규모 양조장에서 생산되는 탁주와 약주의 미생물 군집 분포를 차세대 염기서열 분석기법을 이용하여 조사하였다. 각 시료별로 미생물 분포에 따른 품질의 차이를 나타냈으며 특히 백미 또는 소맥분을 주로 사용한 탁주와 달리 약주는 찹쌀과 백미를 주원료로 사용하여 각각 독특한 주질과 미생물 분포에 영향을 주었다. 주요검출 미생물로 진균류는 S. cerevisiae가 대부분을 차지하였으며 세균의 경우 Firmicutes문에는 유산균인 Lactobacillus, Leuconostoc, Lactococcus, Weisella 속 등이 우점종으로 확인되었다. 곡물인 원재료에 의해 Cyanobacteria 문의 Chloroplast 속과 제조 환경에 의한 유입으로 추정되는 Cronobacter 속, Enterobacter 속 또한 검출되었다. 이러한 다양한 미생물의 분포는 제조 지역, 주원료, 그리고 제조 방법에 기인할 것으로 판단되며 명확한 상관관계는 확인할 수 없었으나 본 연구 결과 유통과정의 제품 안전성 확보를 위해 양조장별 미생물 관리가 필요할 것으로 판단된다.

• Journal of Microbiology and Biotechnology
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• 제16권1호
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• pp.68-76
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• 2006

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 fermention. For the samples over pH 4.0, viable cell counts of Leuconostoc and Pediococcus were $10^6\;cfu/ml$ and below $10^2\;cfu/ml$, respectively, and 20 isolates out of 172 were subjected to a biochemical identification (API 50 CH kit) as well as molecular-typing methods including ITSPCR 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, I carnosum, I 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 isolates, 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 a predominant species in the early phase kimchi fermentation.

• Journal of Microbiology and Biotechnology
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• 제25권12호
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• pp.2090-2099
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• 2015

Recently, the cardiovascular disease has been widely problematic in humans probably due to fibrin formation via the unbalanced Western style diet. Although direct (human plasmin) and indirect methods (plasminogen activators) have been available, bacterial enzyme methods have been studied because of their cheap and mass production. To detect a novel bacterial fibrinolytic enzyme, 111 bacterial strains with fibrinolytic activity were selected from kimchi. Among them, 14 strains were selected because of their stronger activity than 0.02 U of plasmin. Their 16S rRNA sequence analysis revealed that they belong to Bacillus, Leuconostoc, Propionibacterium, Weissella, Staphylococcus, and Bifidobacterium. The strain B. subtilis ZA400, with the highest fibrinolytic activity, was selected and the gene encoding fibrinolytic enzyme (bsfA) was cloned and expressed in the E. coli overexpression system. The purified enzyme was analyzed with SDS-PAGE, western blot, and MALDI-TOF analyses, showing to be 28.4 kDa. Subsequently, the BsfA was characterized to be stable under various stress conditions such as temperature (4-40oC), metal ions (Mn²⁺, Ca²⁺, K²⁺, and Mg²⁺), and inhibitors (EDTA and SDS), suggesting that BsfA could be a good candidate for development of a novel fibrinolytic enzyme for thrombosis treatment and may even be useful as a new bacterial starter for manufacturing functional fermented foods.