• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.371-372
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• 2000

방선균은 생리활성물질의 탐색원으로서 많은 주목을 받고 있는 미생물이지만 현재까지 이용되어온 균주의 대부분은 육상의 토양에서 분리된 것들이고, 해양의 방선균에 관하여서는 아직까지 거의 연구되지 않은 분야이다. 미생물의 서식지로서 해양의 환경조건은 육상과 현저히 다르기 때문에 해양에 있어서 방선균의 microflora는 육상과는 상당히 다를 것으로 생각되어지며, 또한 연안해역에 존재하는 방선균 중에는 육상에서 유입된 담수 등으로 인하여 육상의 토양으로부터 유래된 방선균도 많은 것으로 알려지고 있다. (중략)

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.203-208
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• 2002

미생물 생산은 다양한 산업에 이용되는 핵심산업이다. 그러나 미생물을 장기간 보존하거나 생산 후 현장처리에 상황에 있어 미생물의 활성이 환경 및 각종조건에 따라 장기간 유지되지 못하는 경향이 있다. 따라서, 본 실험에서는 Pseudomonas putida SSEoX의 생산 후 시중에서 판매되는 perlite, diatomite, bentonite, zeolite, dolomite, vermicullite 등의 담체를 이용하여 미생물의 생리활성유지를 위한 실험을 자연현상에서 나타날 수 있는 다양한 온도에서 담체의 종류별로 수행하였다. 그 결과 bentonite를 이용한 담체의 경우 5, 20, 3$0^{\circ}C$에서 40일간 미생물의 밀도가 거의 감소하지 않은 결과로 나타났고 zeolite의 경우 20일 이내의 저온에서 생존율이 높은 것으로 나타났으나 온도의 상승으로 생존율이 현저히 떨어졌다. 또한 Dololite의 경우 초기 20일 내에서는 20t에서 생존율이 매우 높았으나 40일 후 생존율이 현저히 감소하였다. 또한 bentonite의 경우 전체적으로 생존율이 거의 감소되지 않았으며 그중 5$^{\circ}C$와 2$0^{\circ}C$에서 생존율이 가장 높았고 3$0^{\circ}C$에서 30일 후까지는 비교적 적은 감소를 보였으며 40일 이후 비교적 큰 감소율이 있었다. 따라서, 본 실험결과 비교적 낮은 온도에서 bentonite와 vermiculite를 혼합한 담체를 이용한 미생물보존이 가장 우수만 생존유지법이었다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.09a
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• pp.220-223
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• 2001

본 연구에서는 endosulfan으로 오염된 토양을 in-situ flushing으로 정화시 발생되는 세척 유출수의 고정화 미생물에 의한 처리 효율 및 적용성을 검토하였다. 초기 endosulfan 농도 및 pH가 각각 5mg/L, 5.6인 세척유출수의 체류시간을 1, 3, 5시간으로 하여 고정화미생 물 충진 컬럼에 적용한 결과, 제거효율은 각각 62, 82, 89%로 체류시간이 증가될수록 향상되었으며 3가지 조건 모두 약 80시간 이후에 정상상태에 도달하였다. 체류시간 3시간에서 유입수내 endosulfan 농도를 50mg/L 및 100mg/L로 증가시킨 결과, 제거효율이 각각 70% 및 50% 부근까지 저하되었다. 유입수의 pH를 4.0과 9.0으로 변화시켜 실험한 결과 각각 73%와 66%의 제거효율을 나타내었다. pH 9.0보다 4.0에서 제거효율이 약간 높은 이유는 사용 배지의 pH가 약산성을 띠기 때문에 알칼리 상태보다 약산성에서 미생물의 활성이 높기 때문으로 판단된다. 유출수를 재순환 시킨 결과 제거효율이 90%까지 향상되는 것을 볼 수 있었으며, 이는 재 순환되는 유출수의 농도 저감 및 고정화 미생물과의 재 접촉에 기인하는 것으로 판단된다. 유입수에 공기를 주입한 결과, 유출수의 재순환 없이도 약 40시간 후에 93%의 제거효율을 보였으며 이는 미생물 활성의 증가에 기인하는 것으로 판단된다.

• Korean Journal of Microbiology
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• v.27 no.2
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• pp.139-146
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• 1989

The mechanisms and metabolic products involved in the degradation of an organophosphate insecticide, diazinon, were studied in submerged paddy soil under the laboratory condition at $30^{\circ}C$. Diazinon abatement in non-sterilized soil was more rapid than indicating microbial participation in diazinon in soil. One-half of the original applications was lost in 2 days and less than 5% remained after 7 days. During the same period, dizinon applications increased tha microbial populations in accordance with the monooxygenase and esterase activities in soil. These results suggest that the microbiological factors develop in soil following diazinon application. The esterase and monooxygenase-catalyzing degradation products of diazinon were isolated and tentatively identified by mass spectrometryas 2-isopropyle-6-methyl-4-hydroxy pyrimidine, diazoxon, hydroxydiazinon, and sulfotep.

• Journal of Mushroom
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• v.15 no.4
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• pp.237-243
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• 2017

In order to develop fermented silkworm "Dongchunghacho" (Paecilomyces tenuipes) with improved absorption and increased effectiveness, we fermented Dongchunghacho using four kinds of microorganisms, viz., lactic acid bacteria, Bacillus subtilis, Natto bacillus, and yeast. A total of 15 samples were fermented using a combination of microbial inoculation culture and conditions to produce fermentation products. The contents of basic components such as sugar, reducing sugar, protein, total polyphenol, and total flavonoid were examined as well as the antioxidant, tyrosinase inhibitory, and thrombolytic activities of the fermented products were analyzed. We observed that reducing sugar and protein contents decreased in most of the fermented products, but the products fermented using yeast exhibited higher sugar content and, thus, higher sweetness. Total polyphenol content and antioxidant activity did not increase in fermented products compared to non-fermented Dongchunghachos, but total flavonoid content and tyrosinase inhibitory and thrombolytic activities increased by fermentation. In particular, total flavonoid content and tyrosinase inhibitory and thrombolytic activities primarily increased in the products fermented using yeast and lactic acid bacteria. However, it was not possible to confirm the increase in these activities in samples fermented by single fermentation using only yeast. Therefore, we propose that it will be possible to develop fermented food from silkworm Dongchunghacho (P. tenuipes) with excellent health benefits through additional study of multiple fermentation conditions using lactic acid bacteria and yeast.

• Microbiology and Biotechnology Letters
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• v.44 no.3
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• pp.229-235
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• 2016

Korea has a long history of brewing traditional rice wine using a authentic starter culture called nuruk, which contains natural microbial flora. Because rice wine is consumed fresh without filtration, its viable cells contribute to the biological activities of the wine. In numerous studies, microbial strains isolated from rice wine have been screened for their functionalities, which were mainly probiotic properties and antimicrobial activities. Indeed, some lactic acid bacteria (LAB) were confirmed to have strong probiotic activities as well as other health-promoting effects. Moreover, some of the isolated probiotic strains produced functional compounds, such as exopolysaccharides and γ-aminobutyric acid. For antimicrobial activities, some LAB and yeast strains were identified to produce bacteriocins and killer toxins, respectively, with significantly broad spectrum of antimicrobial activity. These functional strains originating from traditional rice wine and their metabolites can be used directly for the production of value-added food products.

• Journal of Life Science
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• v.32 no.1
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• pp.1-10
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• 2022

Natural products have gained increasing attention due to their advantage of long-term safety and low toxicity for a very long time. Torreya nucifera is widespread in southern Korea and Jeju Island and its seeds are commonly used as edible food. Oriental ingredients have often been reported for their insecticidal, antioxidant and antibacterial properties, but there have not yet been any studies on their antidiabetic effect. In this study, we investigated several biological activities of T. nucifera pericarp (TNP) and seeds (TNS) extracts and proceeded to characterize the antidiabetic compounds of TNS. The initial results suggested that TNS extract at 15 and 10 ㎍/ml concentration has inhibitory effects on α-glucosidase and protein tyrosine phosphatase 1B, that is 14.5 and 4.35 times higher than TNP, respectively. Thus, the stronger antidiabetic TNS was selected for the subsequent experiments to characterize its active compounds. Ultrafiltration was used to determine the apparent molecular weight of the active compounds, showing 300 kDa or more. Finally the mixture was then partially purified using Diaion HP-20 column chromatography by eluting with 50~100% methanol. Therefore we concluded that the active compounds of TNS have potential as therapeutic agents in functional food or supplemental treatment to improve diabetic diseases.

• Microbiology and Biotechnology Letters
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• v.49 no.1
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• pp.111-119
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• 2021

A bacterial strain isolated from a Malva verticillata leaf was identified as Bacillus velezensis MV2 based on the 16S rRNA sequencing results. Complete genome sequencing revealed that B. velezensis MV2 possessed a single 4,191,702-bp contig with 45.57% GC content. Generally, Bacillus spp. are known to produce diverse antimicrobial compounds including bacteriocins, polyketides, and non-ribosomal peptides. Antimicrobial compounds in the B. velezensis MV2 were extracted from culture supernatants using hydrophobic interaction chromatography. The crude extracts showed antimicrobial activity against both gram-positive bacteria and gram-negative bacteria; however, they were more effective against gram-positive bacteria. The extracts also showed antifungal activity against phytopathogenic fungi such as Fusarium fujikuroi and F. graminearum. In time-kill assays, these antimicrobial compounds showed bactericidal activity against Bacillus cereus, used as indicator strain. To predict the type of antimicrobial compounds produced by this strain, we used the antiSMASH algorithm. Forty-seven secondary metabolites were predicted to be synthesized in MV2, and among them, fourteen were identified with a similarity of 80% or more with those previously identified. Based on the antimicrobial properties, the antimicrobial compounds may be nonribosomal peptides or polyketides. These compounds possess the potential to be used as biopesticides in the food and agricultural industry as an alternative to antibiotics.

• Microbiology and Biotechnology Letters
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• v.10 no.3
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• pp.171-175
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• 1982

An oxytetracycline as being a tetracycline-antibiotic substance displayed a general synergism in the antimicrobial activity by the interaction of ginseng saponin and antibiotics, but did not to Sarcina maginata. Penicillin G.Na as being a $\beta$-lactam-antibiotic substance displayed a synergism in the antimicrobial activities by the addition of ginseng saponin to microorganisms used, but changed the effects in the antimicrobial activity of penicillin G.Na against the genus Serratia. An antimicrobial activity by the addition of ginseng saponin to antibiotics showed a non-specificity, and it varied synergism or antagonism to Gram-positive or Gram-negative bacterium. It was assumed that a drug-resistance could be eliminated by the dual administration of ginseng saponin and antibiotics.

• Korean Journal of Microbiology
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• v.39 no.4
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• pp.230-234
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• 2003

An extracellular protease of Bacillus amyloliquefaciens S94 was purified to apparent homogeneity. The enzyme activity was strongly inhibited by general inhibitor for serine protease, PMSF, suggesting that the enzyme is a serine protease. The purified enzyme activity was inhibited by leucine peptidase inhibitor, bestatin, suggesting that the enzyme is a leucine endopeptidase. When the enzyme was chemically modified with PMSF, which specifically reacted with serine residue on the enzyme, the activity was eliminated. The endopeptidase activity was inhibited by the modifier which chemically modified carboxyl group of aspartate and glutamate. PLP, which would modify lysine residue, did not affect the endopepetidase activity to a greater extent. This demonstrates that serine and aspartate (or glutamate) residues of enzyme would participate in a important function of the endopeptidase activity.