• Journal of Ginseng Research
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• 제21권2호
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• pp.69-77
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• 1997

In order to explain the connection between ginseng rust spot and soil ecological conditions, the bed soils and ginseng roots were sampled at different microrelief units and the reducing substances of the bed soils and iron forms of the ginseng root epi dermises were determined. The results showed that the occurrence of the rust spot was connected with the ecological conditions of the soils and the metabolism of the plant which was caused by the excessive $Fe^{2+}$ in the soil solution. Ginseng rust spot was the enrichment of iron which was mainly composed of organic complex irons. Including active ferrous active ferric and non active ferric forms and they were transformed into each other following the change of soil moisture and temperature regimes. According to the regularity of growth and decline of reducing substances in soil and rust index of ginseng roots as well as the difference of adaptability to excessive $Fe^{2+}$ in soil among different year-old seeding, a new comprehensive measure based on the connection of ameliorating soil and improving cultivation system was recommended to prevent the occurrence of ginseng rust spot.

• 한국환경과학회지
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• 제9권3호
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• pp.267-273
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• 2000

In order to understand the impact for decomposition of blue-green algae Microcystis on water quality, the algae were cultivated with collection of natural population during approximately one month, when water-bloom of Microcystis dominated at August 31, 1999 in the lower part of the Okchon Stream. The enrichment of inorganic NㆍP nutrients didn't in algal assay and the effect of Microcystis on water duality was assessed from the variation of nutrients by algal senescence. Microcystis population seemed to play a temporary role of sink for nutrients in the water body. Initial algal density of Microcystis was 2.3×10/sup 6/ cells/㎖. When Microcystis population died out under light condition, algal NㆍP nutrients between 9∼12 days affected to increase of biomass after reuse by other algal growth as soon as release to the ambient water. However, cellular nutrients under dark condition were almost moved into the water during algal cultivation. NH₄, NO₃ and SRP concentration were highly increased with 160, 17 and 79 folds, respectively relative to the early. As a result, the senescence of Microcystis population seemed to be an important biological factor in which cause more eutrophy and increase of explosive algal development by a lot of nutrients transfer to water body. There are significantly observed an effort of reduce for production of inner organic matters such a phytoplankton as well as load pollutants from watershed in side of the water quality management of reservoir.

• KSBB Journal
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• 제18권6호
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• pp.461-465
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• 2003

질소함유 폐수를 생물학적으로 효과적으로 처리하기 위한 전 단계로서 탈질 균을 분리하여 최종 선정된 균주의 분해특성을 조사한 결과 다음과 같은 결론을 얻었다. 분리된 5개 균주 가운데 DWS3가 세포성장과 질산성질소 제거율이 가장 우수하여 최종 분리 균주로 선정하였다. DWS3를 동정한 결과 Pseudomonas DWS로 명명하였다. 반 유동성 사면배지에 배양한 결과 녹색을 띠었으나, 탈질능을 갖는 균주의 활성에 따라 배지의 색이 녹색에서 암녹색으로 변환되었다. Pseudomonas DWS는 4시간 정도의 유도기를 거쳐 18시간에 최대 증식을 나타내었으며, 균의 생육속도와 비례하여 질산성질소의 제거율이 증가하는 것으로 나타났다. Pseudomonas DWS의 온도별 특성은 3$0^{\circ}C$에서 성장과 탈질율이 99% 우수하게 나타났으나, 탈질균 성장에 적합한 초기 pH는 7∼8에서 질산성 질소가 99% 이상 거의 모두 제거되었다. Pseudomonas DWS는 질산성 질소 농도에 관계없이 9시간 이내에 배지의 질산성 질소가 약 50%가 제거되었으며, 18시간 경과 후 99% 이상 질산성 질소가 제거되었다. 따라서 Pseudomonas DWS는 질소화합물을 다량 포함된 하, 폐수의 생물학적 처리에 효과적으로 이용 될 수 있는 것으로 사료된다.

• 한국환경과학회지
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• 제11권3호
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• pp.177-182
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• 2002

A biosurfactant-producing microorganism was isolated from activated sludge by enrichment culture when grown on a minimal salt medium containing n-hexadecane as a sole carbon source. This microorganism was identified as Pseudomonas sp. and it was named Pseudomonas sp. EL-G527. It's optimal culture condition is 2% n-hexadecane, 0.2% NH$_4$NO$_3$, 0.3% KH$_2$PO$_4$, 0.3% $K_2$HPO$_4$, 0.02% MgSO$_4$ㆍ7$H_2O$, 0.0025% CaCk$_2$ㆍ6$H_2O$, 0.0015% FeSO$_4$ㆍ7$H_2O$ in 1$\ell$ distilled water and initial pH 7.0. Cultivation was initiated with a 2% inoculum obtained from starter cultures grown in 30 $m\ell$ of the same medium in 250 $m\ell$ flask. They were cultivated at 3$0^{\circ}C$ in reciprocal shaking incubator and the highest biosurfactant production was observed after 4 days.

• Journal of Microbiology
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• 제37권4호
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• pp.200-205
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• 1999

7-Aminocephalosporanic acid (7-ACA) is the initial compound in preparation of cephalosporin antibiotics widely used in clinical treatment. Bacteria producing glutaryl 7-ACA acylase, which convert cephalosporin C to 7-ACA, has been screened in soil samples. A bacterial strain exhibiting high glutaryl 7-ACA acylase activity, designated KAC-1, was isolated and identified as a strain of Pseudomonas diminuta by characterizing its morphological and physiological properties. The screening procedures include culturing on enrichment media containing glutaric acid, glutamate, and glutaryl 7-aminocephalosporanic acid as selective carbon sources. To enhance enzyme production, optimal cultivation conditions were investigated. This strain grew optimally at pH 7 to 9 and in temperatures of 20 to 40 C, but acylase production was higher when the strain was grown at 25 C. Glutaric acid, glutamate and glucos also acted as inducers for acylase production. In a jar fermenter culture, P. diminuta KAC-1 produce acylase in a growth-associated manner. The substrate specificity of KAC-1 acylase by cell extract showed that this enzyme had specificity toward glutaryl 7-ACA, glutaryl 7-ADCA, but not cephalosporin C.

• Bulletin of the Korean Chemical Society
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• 제30권12호
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• pp.2993-2998
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• 2009

An enzyme-linked immunosorbent assay (ELISA)-on-a-chip (EOC) biosensor combined with cell concentration technology based on immuno-magnetic separation (IMS) was investigated for use as a potential tool for early screening of Listeria monocytogenes (L. monocytogenes) in food products. The target analyte is a well-known pathogenic foodborne microorganism and outbreaks of the food poisoning typically occur due to contamination of normal food products. Thus, the aim of this study was to develop a rapid and reliable sensor that could be utilized on a daily basis to test food products for the presence of this pathogenic microorganism. The sensor was optimized to provide a high detection capability (e.g., 5.9 ${\times}\;10^3$ cells/mL) and, to eventually minimize cultivation time. The cell density was condensed using IMS prior to analysis. Since the concentration rate of IMS was greater than 100-fold, this combination resulted in a detection limit of 54 cells/mL. The EOC-IMS coupled analytical system was then applied to a real sample test of fish intestines. The system was able to detect L. monocytogenes at a concentration of 2.4 CFU/g after pre-enrichment for 6 h from the onset of cell cultivation. This may allow us to monitor the target analyte at a concentration less than 1 CFU/g within a 9 h-cultivation provided a doubling time of 40 min is typically maintained. Based on this estimation, the EOC-IMS system can screen and detect the presence of this microorganism in food products almost within working hours.

• 생물환경조절학회지
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• 제31권4호
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• pp.485-496
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• 2022

국내외로 첨단 ICT 융합기술이 농업 분야에 적용되기 시작하면서, 시설원예 설비들이 고도화되고, 스마트팜 구축 기술 및 인력이 축적되기 시작하였다. 그러나 우리나라 농촌의 경우, 농업생산 연령의 고령화, 국내 농촌 인구의 지속적인 유출, 저출산 등으로 인하여 스마트팜 확대 및 적용에 어려움이 많은 실정이다. 따라서 공간 및 시간에 구속을 받지 않는 간편한 농업인 교육 프로그램이 필요하며, 최근 부상하고 있는 시뮬레이션 기술을 활용한다면 농업 교육용 시뮬레이션 툴 개발도 가능할 것으로 판단된다. 온실 환경 제어 모델을 이용한 시뮬레이션은 다양한 지역과 기상 조건 하에서 대상 온실의 열과 물질에너지의 상호작용을 합리적으로 예측할 수 있게 해준다. 본 연구에서는 온실 환경 제어 모델을 활용하여 외부 기상 데이터를 통해 온실의 환경 변화를 예측하고 가상의 환경 제어시스템을 통해 환경 제어 시 필요한 에너지값들을 시뮬레이션 할 수 있었다. 이러한 결과를 통해 이용자가 직접 맞춤형 환경 제어를 할 수 있도록 편의성을 고려한 사용자 인터페이스를 구축할 것이며, 실제 파프리카 재배 온실의 제어 요소들을 반영할 수 있도록 설계될 것이다. 농업용 교육 시뮬레이션 툴을 최근 활발하게 연구가 이루어지고 있는 작물 생육 모델링 기술 및 전산유체역학 기술과 융합하면 더욱타당한 결과를 보일 것이다.

• 원예과학기술지
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• 제30권3호
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• pp.270-277
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• 2012

Greenhouse industry has been growing in many countries due to both the advantage of stable year-round crop production and increased demand for fresh vegetables. In greenhouse cultivation, $CO_2$ concentration plays an essential role in the photosynthesis process of crops. Continuous and accurate monitoring of $CO_2$ level in the greenhouse would improve profitability and reduce environmental impact, through optimum control of greenhouse $CO_2$ enrichment and efficient crop production, as compared with the conventional management practices without monitoring and control of $CO_2$ level. In this study, a mathematical model was developed to estimate the $CO_2$ emission from soil as affected by environmental factors in greenhouses. Among various model types evaluated, a linear regression model provided the best coefficient of determination. Selected predictor variables were solar radiation and relative humidity and exponential transformation of both. As a response variable in the model, the difference between $CO_2$ concentrations at the soil surface and 5-cm depth showed are latively strong relationship with the predictor variables. Segmented regression analysis showed that better models were obtained when the entire daily dataset was divided into segments of shorter time ranges, and best models were obtained for segmented data where more variability in solar radiation and humidity were present (i.e., after sun-rise, before sun-set) than other segments. To consider time delay in the response of $CO_2$ concentration, concept of time lag was implemented in the regression analysis. As a result, there was an improvement in the performance of the models as the coefficients of determination were 0.93 and 0.87 with segmented time frames for sun-rise and sun-set periods, respectively. Validation tests of the models to predict $CO_2$ emission from soil showed that the developed empirical model would be applicable to real-time monitoring and diagnosis of significant factors for $CO_2$ enrichment in a soil-based greenhouse.

• 한국환경과학회지
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• 제6권2호
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• pp.153-163
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• 1997

In order to fad the most fitted biodegradation model, biodegradation kinetics model to the initial phenol and p-cresot concentrations were investigated and had been fitted by the linear regression. Bacteria capable of degrading p-cresol were isolated from soil by enrichment culture technique. Among them, strain Ml capable of degradillg p.rcresol has also degraded phenal and was identified as the genus Micrococcus from the results from of taxonomical studies. The optimal tonditlons for the biodegradation of phenal and p-cresol by Micrococcus sp. Ml were $NH_4NO_3$ 0.05%, pH 7.0, 3$0^{\circ}C$, respectively, and medium volume 100m1/250m1 shaking flask. iwicrococcus sp. Ml was able to grow on phenal concentration up to 14mM and p-cresol concelltration up to 0.8mM. With increasing substrate concentraction, the lag period increased, but the maximum specific growth rates decreased. The yield coefficient decreased with increasing substrate concentation. The biodegradation kinetics of phenol and p-cresol were best described by Monod with growth model for every experimented concentration. In cultivation of mixed substrate, p-cresol was degraded first and phenol was second. This result implies that p-cresol and phenol was not degraded simultaneously.

• Journal of Microbiology and Biotechnology
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• 제20권4호
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• pp.828-834
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• 2010

An ethanol-producing yeast strain, CHFY0201, was isolated from soil in South Korea using an enrichment technique in a yeast peptone dextrose medium supplemented with 5% (w/v) ethanol at $30^{\circ}C$. The phenotypic and physiological characteristics, as well as molecular phylogenetic analysis based on the D1/D2 domains of the large subunit (26S) rDNA gene and the internally transcribed spacer (ITS) 1+2 regions, suggested that the CHFY0201 was a novel strain of Schizosaccharomyces pombe. During shaking flask cultivation, the highest ethanol productivity and theoretical yield of S. pombe CHFY0201 in YPD media containing 9.5% total sugars were $0.59{\pm}0.01$ g/l/h and $88.4{\pm}0.91%$, respectively. Simultaneous saccharification and fermentation for ethanol production was carried out using liquefied cassava (Manihot esculenta) powder in a 5-l lab-scale jar fermenter at $32^{\circ}C$ for 66 h with an agitation speed of 120 rpm. Under these conditions, S. pombe CHFY0201 yielded a final ethanol concentration of $72.1{\pm}0.27$ g/l and a theoretical yield of $82.7{\pm}1.52%$ at a maximum ethanol productivity of $1.16{\pm}0.07$ g/l/h. These results suggest that S. pombe CHFY0201 is a potential producer for industrial bioethanol production.