• KSBB Journal
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• 제13권5호
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• pp.469-476
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• 1998

Among 31 water-born microbial strains isolated from various sites in Korea, strain DJ-4 was selected as a test organism for toxicity measurements in that its growth was completely inhibited by the presence of 668.4 mg/L of chloroform and 297.5 mg/L of toluene in the liquid LB medium whereas others did not. It was observed that lag periods and specific growth rates of DJ-4 batch vial cultures were prolonged and decreased, respectively, by phenol, benzene, toluene, ethylbenzene, p-xylene, perchloroethylene, trichloroethylene, and chloroform at the concentrations between 3.6 and 417.8 mg/L. There changes were found to be linear with respect to the concentrations of the toxic compounds. From the first-order regression equations, 50% effective concentrations (EC50${\mu}$ for concentrations of toxic compounds causing 50% decrease of specific growth rates and EC50lag for 50% increase of length of lag periods) were calculated for each compounds. By comparing DJ-4 EC50${\mu}$ values with Daphnia LC50's from a literature for benzene, ethylbenzene, toluene, and trichloroethlyene, it was concluded that microbial specific growth could be a new, fast, and reliable parameter for toxicity tests.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권5호
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• pp.408-417
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• 2005

Increasing numbers of value added chemicals are being produced using microbial fermentation strategies. Computational modeling and simulation of microbial metabolism is rapidly becoming an enabling technology that is driving a new paradigm to accelerate the bioprocess development cycle. In particular, constraint-based modeling and the development of genome-scale models of industrial microbes are finding increasing utility across many phases of the bioprocess development workflow. Herein, we review and discuss the requirements and trends in the industrial application of this technology as we build toward integrated computational/experimental platforms for bioprocess engineering. Specifically we cover the following topics: (1) genome-scale models as genetically and biochemically consistent representations of metabolic networks; (2) the ability of these models to predict, assess, and interpret metabolic physiology and flux states of metabolism; (3) the model-guided integrative analysis of high throughput 'omics' data; (4) the reconciliation and analysis of on- and off-line fermentation data as well as flux tracing data; (5) model-aided strain design strategies and the integration of calculated biotransformation routes; and (6) control and optimization of the fermentation processes. Collectively, constraint-based modeling strategies are impacting the iterative characterization of metabolic flux states throughout the bioprocess development cycle, while also driving metabolic engineering strategies and fermentation optimization.

• 원예과학기술지
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• 제29권5호
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• pp.467-473
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• 2011

Flavonoid are large group of the polyphenolic compounds which are distinguished by an aromatic or phenolic ring structure and the phenolic compounds are induced by microbial infection, ultraviolet radiation, temperature and chemical stress. They are known for their antioxidant activity, anti-allergic, anti-inflammatory, anti-microbial and anti-cancer activities. In this study, changes in flavonoid content were investigated using heterologous chalcone isomerase (CHI) expression system. Also, phenolic compounds level was measured to examine the relation between flavonoids and phenols contents. Explants of lettuce (Lactuca sativa L.) were transformed with Agrobacterium tumefaciens LBA 4404 strain containing pFLH-CHI (derived from pPZP2Ha3) vector constructed with CHI gene from Brassica rapa. The putative transgenic plants were confirmed by genomic DNA PCR analysis. Also the transcription levels of the gene were analyzed by semi-quantitative RT-PCR with gene specific primers. The total flavonoid contents were increased at $T_0$ and $T_1$ generations over 1.4 and 4.0 fold, respectively. Total phenol contents also increased at $T_1$ generation. These results indicate that CHI gene plays an important role to regulate the accumulation of flavonoids and its component changes.

• 생약학회지
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• 제48권3호
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• pp.219-225
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• 2017

We investigated the anti-oxidative effect of the blueberry duke (Vaccinium corymbosum L., Ericaceae) ethanol extract in Caenorhabditis elegans model. The ethanol extract of blueberry duke showed relatively significant DPPH radical scavenging and superoxide quenching activities. To prove antioxidant activity of the extract, we checked the activities of superoxide dismutase (SOD), catalase, intracellular ROS, and oxidative stress tolerance in C. elegans. In addition, to verify if the increased stress tolerance of C. elegans by treating with the extract was due to regulation of stress-response genes, we checked SOD-3 expression using a transgenic strain. As a consequence, the blueberry duke ethanol extract increased SOD and catalase activities of C. elegans, and reduced intracellular ROS accumulation in a dose-dependent manner. Besides, blueberry duke ethanol extract-treated CF1553 worms showed higher SOD-3::GFP intensity.

• Journal of Applied Biological Chemistry
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• 제56권2호
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• pp.119-129
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• 2013

Thirteen different Streptomyces isolates were evaluated for their ability to produce keratinase using chicken feather as a sole carbon and nitrogen sources under solid state fermentation (SSF). Streptomyces sp. NRC 13S produced the highest keratinase activity [1,792 U/g fermented substrate (fs)]. The phenotypic characterization and analysis of 16S rDNA sequencing of the isolate were studied. Optimization of SSF medium for keratinase production by the local isolate, Streptomyces sp. NRC13S, was carried out using the one-variable-at-a-time and the statistical approaches. In the first optimization step, the effect of incubation period, initial moisture content, initial pH value of the fermentation medium, and supplementation of some agro-industrial by-products on keratinase production were evaluated. The strain produced about 2,310 U/gfs when it grew on chicken feather with moisture content of 75% (w/w), feather: fodder yeast ratio of 70:30 (w/w), and initial pH 7 using phosphate buffer after 8 days. Based on these results, the Box-Behnken design and response surface methodology were applied to find out the optimal conditions for the enzyme production. The corresponding maximal production of keratinase was about 2,569.38 U/gfs.

• Fisheries and Aquatic Sciences
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• 제15권2호
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• pp.91-97
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• 2012

To isolate a nonylphenol (NP)-degrading bacterium, we isolated a single colony from the NP-degrading microbial consortium SW-3, which was previously isolated from an aqueous environment. Ten colonies that exhibited different cell morphologies were isolated and the strains were named SW-3-A, -B, -C, -D, -E, -F1, -F2, -G, -H, and -I. The ability of isolates to degrade NP was evaluated by kinetic analysis by the constant of NP degradation rate ($k_1$) and the half-life time of NP degradation ($t_{1/2}$). SW-3-F1, -F2, -G, and -I strains were superior at degrading NP. The $k_1$ and $t_{1/2}$ values of the four strains were sixfold higher and one-sixth lower, respectively, than those of the consortium strain. Additionally, SW-3-F1, -G, and -I strains were tested for their ability to degrade NP during coculture. NP degradation by coculture with a combination of all three strains was inferior to that of culture conducted with single isolates, suggesting that the three strains are antagonistic toward each other during NP degradation.

• 한국미생물·생명공학회지
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• 제19권1호
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• pp.88-93
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• 1991

유지함유폐수를 생물학적으로 처리할 목적으로 폐수 및 토양으로부터 45종의 균을 분리 동정하여, 그 중에서 COD 제거율과 유지제거율이 우수한 LW-27균을 선발 동정하였다. 동정결과 LW-27 균은 Pseudomonas chlororapihis의 유연균으로 동정됐다. LW-27균의 제제화는 $45^{\circ}C$에서 24시간 진공건조하여 82%이상의 균 생존율을 얻어 제제화하였다. 제제된 LW27을 0.1g 매일 확성슬러지장치에 처리하면서 혼합폐수를 연속 처리한 결과 처리수의 COD, BOD 및 n-헥산 추출물질의 농도의 제거율이 평균 92.95, 94.%8 및 98%.0로 나타났다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제3권2호
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• pp.71-77
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• 1998

The strain of Serratia marcescens QM B1466 produces selectively large amount of chitinolytic enzymes (about 1mg/L medium). Enzymatic hydrolysis of chitin to N-acetyl-${\beta}$-D-glucosamine (NAG) was performed with a system consisting of two hydrolases (chitinase and chitobiase) produced by optimization of a microbial host consuming chitin particles. For the development of Large-scale biological process for the production of NAG from chitinaceous waste, the selection and optimization of a microbial host, particle size of crab/shrimp chitin sources and initial induction time using chitin as a sole carbon source on chitinase/chitobiase production and NAG production were examined. Crab-shell chitin(1.5%) treated by dilute acid and , ball-milled with a normal diameter less than 250m gave the highest chitinase activity over a 7 days culture. Crude chitinase/ chitobiase solution obtained in a 10 L fed-batch fermentation showed a maximum activities of 23.6 U/mL and 5.1 U/mL, respectively with a feeding time of 3 hrs, near pH 8.5 at 30$^{\circ}C$.

• 한국식품조리과학회지
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• 제4권1호
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• pp.41-46
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• 1988

오미자차액은 여름철의 음료나 화채의 기액으로서 많이 사용하고 있는데, 그 열매는 산을 많이 함유하고 있어 pH가 낮아(2.8-3.0) 미생물의 성장을 효과적으로 저해할 수 있는 pH를 가지나 $25^{\circ}C$에 저장했을 때 부패가 일어나는 것이 확인되었고 부패균은 곰팡이와 효모이었으며 세균은 관찰되지 않았다. 저장 중 부패되고 있는 오미자차액의 적정산도나 pH에는 그다지 큰 변화가 없었고 열매를 걸러낸 오미자차액에서의 적정산도는 열매가 들어있는 오미자차액보다 낮았는데, 그 이유는 열매가 들어 있는 오미자차액의 열매에서 산이 계속 용출되어 나왔기 때문으로 판단된다. 열매를 거른 오미자차액의 부패가 열매가 들어 있는 오미자차액보다 조금 빠르며 그 저장성도 열매를 거른 오미자차액이 낮은 것으로 나타났다. 그러나 오미자차액의 색상과 맛의 효과로서는 걸러서 보관하되 장기적인 저장은 바람직하지 못하다.

• 한국식품영양학회지
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• 제22권1호
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• pp.97-102
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• 2009

본 연구에서는 독성이 적고, 활성이 높으면서 안정한 새로운 tyrosinase 저해제를 미생물을 대상으로 얻고자 tyrosinase 저해제를 강하게 분비하는 방선균 F-97을 토양으로부터 분리하였다. 이 균의 기균사는 회색의 나뭇가지형 (tree type)이며, 포자의 끝부분이 유선형으로 회전되어 있고, 포자 표면은 구형의 smooth형으로 분류되었다. 세포벽의 DAP 성분은 LL-DAP이었으며, 세포균체의 당 성분은 검출되지 않았다. 기타 배양학적 및 생리적 특성을 종합한 결과 streptomyces aburaviensis 또는 근연균으로 추정된다.