• Korean Journal of Environmental Agriculture
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• v.12 no.2
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• pp.129-143
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• 1993

The objective of this study is to understand the status of the water pollution in rural areas and to furnish a basic material for the management of the water pollution in rural areas. For this purpose, the Bokha river basin, Ichon-Gun, Kyungki-Do considering as a typical agricultural area was selected as a representative experimental watershed. The characteristics of water pollution in streams of the Bokha river basin was revealed by investigating and analyzing data collected for the source of pollution, water qualities in reaches of the stream, the degree of contribution to the river contamination by pollution mass produced from each source, and the status of the self-purification at the main stream. The most important source of the water pollution in investigated watershed was livestock, and the next important one were in the order of population, land use, and industry. The water quality of the Bokha river was relatively favorable judging from the BOD and COD concentration, however since the concentration of T-N and T-P showed significantly large values, it was concluded that the river was seriously contaminated by the nutrient material. The main cause of the river contamination was proved due to livestock waste. For the T-N, both land use and livestock were much more contributied to the pollution than any other source, which characterized the typical water pollution of rural areas. Run-off ratios for the Bokha river tributaries to the main stream were changed according to the similar trend to the variation of discharges in the branch streams. For the value of the self-purification constant at the main stream, it showed smaller value in the downstream reach than the middle-stream and upstream reaches, where could possibly have smaller reoxidation action due to slower velocity and deeper water depth.

• Plant Journal
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• v.18 no.4
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• pp.58-65
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• 2023

In this study, to increase the methane content of biogas supplied from Nanji Water Regeneration Center and to purify impurities, a three-stage membrane purification process was designed and installed to demonstrate operation. The methane concentration of biomethane produced in the 2 Nm3/h purification process was set to three cases: 95%, 96.5%, and 98%, and the membrane area ratio of the membrane was 1:1, 1:2, 1:1:1, The optimum conditions for the membrane area of the separator were derived by changing to five of 1:2:1 and 1:2:2. 3 stage separation membrane process of 30 Nm3/h was installed to reflect the optimum condition of 2 Nm3/h, and biomethane production of 98% or more of methane concentration was demonstrated. As a result of the operation of the 2 Nm³/h refining device, the methane recovery rate at the 98% methane concentration was 95.6% when the membrane area ratio was 1:1 as the result of the two-stage operation of the separator, and the recovery rate of methane at 1:2 was increased to 96.8%. The methane recovery rate of the membrane three-stage operation was highest at 96.8% when the membrane area ratio was operated at 1:2:1. The carbon dioxide removal rate was 16.4 to 96.4% and the 2:2 to 95.7% film area ratio in the two-step process. In the three-step process, the film area ratio was 1:2:1 to 95.4%, and the two-step process showed higher results than the three-step process. In the 30 Nm3/h scale biogas purification demonstration operation, the methane concentration after purification was 98%, the recovery rate of methane was 97.1%, the removal rate of carbon dioxide was 95.7%, and hydrogen sulfide, the cause of corrosion, was not detected, and the membrane area ratio was 1:2:1 demonstration operation, biomethane production with a methane concentration of 98% or higher was possible.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.4
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• pp.556-561
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• 1997

Vibrio cholerae non-O1 FM-3 was isolated from sea water, and it showed the same bacteriological characteristics as Vibrio cholerae non-O1 ATCC 25872. V. cholerae non-O1 FM-3 presented the highest hemolytic activity at stationary phase of its growth. The hemolytic activity was decreased in accordance with increasing of pretense activity of its cultural supernatant. The characteristics of the hemolysin produced by V. cholerae non-O1 FM-3 were investigated after partial purification with a Sephadex G-100 chromatography. The hemolytic activity of purified protein was stable at $4^{\circ}C$ while it was completely lost by heating at $60^{\circ}C$ for 30 min. The activity of hemolysin was increased by addition of divalent cations such as $Ca^{2+},\;Mg^{2+},\;and\;Mn^{2+}$ while it was inhibited by additions of $Zn^{2+}$. When the hemolysin was incubated with suspensions of erythrocytes at $4^{\circ}C$ and $37^{\circ}C$, respectively, hemolysis was not observed at $4^{\circ}C$ but at $37^{\circ}C$. It means that hemolysis by purified hemolysin was temperature-dependent while its binding step of hemolysin to cell membrane was temperature-independent.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.40-44
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• 2003

Soil-borne infectious disease including Pythium aphanidermatum and Rhizoctonia solani causes severe damage to plants, such as cucumber. This soil-borne infectious disease was not controlled effectively by chemical pesticide. Since these diseases spread through the soil, chemical agents are usually ineffective. Instead, biological control, including antagonistic microbe can be used as a preferred control method. An efficient method was developed to select an antagonistic strain to be used as a biological control agent strain. In this new method, surface tension reduction potential of an isolate was included in the ‘decision factor’ in addition to the other factors, such as growth rate, and pathogen inhibition rate. Considering these 3 decision factors by a statistical method, an isolate from soil was selected and was identified as Bacillus sp. GB16. In the pot test, this strain showed the best performance among the isolated strains. The lowest disease incidence rate and fastest seed growth was observed when Bacillus sp. GB16 was used. Therefore this strain was considered as plant growth promoting rhizobacteria (PGPR). The action of surface tension reducing component was deduced as the enhancement of wetting, spreading, and residing of antagonistic strain in the rhizosphere. This result showed that new selection method was significantly effective in selecting the best antagonistic strain for biological control of soil-borne infectious plant pathogen. The antifungal substances against P. aphanidermatum and R. solani were partially purified from the culture filtrates of Bacillus sp. GB16. In this study, lipopeptide possessing antifungal activity was isolated from Bacillus sp. GB16 cultures by various purification procedures and was identified as a surfactin-like lipopeptide based on the Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), high performance liquid chromatography mass spectroscopy (HPLC-MS), and quadrupole time-of-flight (Q-TOF) ESI-MS/MS data. The lipopeptide, named GB16-BS, completely inhibited the growth of Pythium aphanidermatum, Rhizoctonia solani, Penicillium sp., and Botrytis cineria at concentrations of 10 and 50 mg/L, respectively. A novel method to prevent the foaming and to provide oxygen was developed. During the production of surface active agent, such as lipopeptide (surfactin), large amount of foam was produced by aeration. This resulted in the carryover of cells to the outside of the fermentor, which leads to the significant loss of cells. Instead of using cell-toxic antifoaming agents, low amount of hydrogen peroxide was added. Catalase produced by cells converted hydrogen peroxide into oxygen and water. Also addition of corn oil as an oxygen vector as well as antifoaming agent was attempted. In addition, Ca-stearate, a metal soap, was added to enhance the antifoam activity of com oil. These methods could prevent the foaming significantly and maintained high dissolved oxygen in spite of lower aeration and agitation. Using these methods, high cell density, could be achieved with increased lipopeptide productivity. In conclusion to produce an effective biological control agent for soil-borne infectious disease, following strategies were attempted i) effective screening of antagonist by including surface tension as an important decision factor ii) identification of antifungal compound produced from the isolated strain iii) novel oxygenation by $H_2O_2-catalase$ with vegetable oil for antifungal lipopeptide production.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.25-33
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• 2018

Renewable energy has been of interests in the area of modern alternative fuels. Biogas is produced in waste landfill sites through anaerobic digestion processes, including hydrolysis, acidogenesis, organic acid fermentation (acetogenesis), and methane fermentation (methanogenesis). High contents of fine dust and moisture limited its utilization for direct combustion, town gas and vehicle fuel. Thus, this study proposed a new design for a cooling device using a centrifugal cyclone for simultaneous removal of fine dust and moisture as a pretreatment in the purification processes. A heat exchanger and an ID fan, which are installed inside and outside of the cyclone, in order to cool the humid gas below the freezing point and form a foggy mist. Such an atmosphere enhanced to capture fine dust as recirculating the cold mist flow. The water removal rate was 80.8% at a relative humidity of 95%, and the particle removal efficiency was 98.3% for $2.5{\mu}m$. Simultaneous removal efficiency was 70.8% and 99.6% for particle and moisture respectively.

• Journal of Microbiology and Biotechnology
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• v.17 no.4
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• pp.638-643
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• 2007

The full encoding sequence for human type II hexokinase (HXK II) was cloned into the E. coli expression vector pET 21b and expressed as a C-terminally hexahistidine-tagged protein in the BL2l (DE3) strain. The IPTG-induced HXK II approximately accounted for 17% of the total E. coli proteins, and 81% of HXK $II_{6{\times}His}$ existed in inclusion bodies. To improve the production of soluble recombinant HXK II protein, in the functionally active form, we used low temperature, and the osmotic stress expression method. When expressed at $18^{\circ}C$, about 83% of HXK $II_{6{\times}His}$ existed in the soluble fraction, which amounted to a 4.1-fold yield over that expressed at $37^{\circ}C$. The soluble form of HXK $II_{6{\times}His}$ was also highly produced in the presence of 1M sorbitol under the standard condition $(37^{\circ}C)$, which indicated that temperature downshift and low water potentials were required to improve the yield of active recombinant HXK II protein. The expressed protein was purified by metal chelate affinity chromatography performed in an IDA Excellose column charged with $Ni^{2+}$ ions, resulting in about 40mg recombinant HXK II protein obtained with purity over 89% from 51 of E. coli culture. The identity of HXK $II_{6{\times}His}$ was confirmed by Western blotting analysis. Taken together, using the stress-governed expression described in this study, human active HXK II can be purified in sufficient amounts for biochemical and biomedical studies.

• Korean Chemical Engineering Research
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• v.52 no.6
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• pp.755-767
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• 2014

Chlorine is one of the most produced and most used non-flammable chemical substances in the world even though its toxicity and high reactivity cause the ozone layer depletion. However, in modern life, it is impossible to live a good life without using Chlorine and its derivatives since they are being used as an typical ingredient in more than 40 percent of the manufactured goods including medicines, detergents, deodorant, fungicides, herbicides, insecticides, and plastic, etc. Even if Chlorine has been handled and distributed in various business (small and medium-sized businesses, water purification plants, distribution company, etc.), there have been few researches about its possible health hazard and transportation risks. Accordingly, the purpose of this paper is to make a detailed assessment of Chlorine-related risks and to model an index of chemicals transportation risks that is adequate for domestic circumstances. The assessment of possible health hazard and transportation risks was made on 13 kinds of hazardous chemicals, including liquid chlorine. This research may be contributed to standardizing the risk assessment of Chlorine and other hazardous chemicals by using an index of transportation risks.

• Applied Biological Chemistry
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• v.15 no.1
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• pp.27-33
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• 1972

The alkaline protease was isolated from the culture material of monascus sp. on wheat bran culture. The crude purification of this enzyme was extracted with distilled water and precipitated with ammonium sulfate of 0.5 saturation. And, the activity of this enzyme was determind very strongly by folin's colorimetric method. The optimal pH of this enzyme was ranging from pH 10 to 13 and the optimal temperature was $50^{\circ}C$. The pH stability was ranging from pH 5 to 12 and the enzyme activity was not inactivated by heat treatment in lower temperature than $40^{\circ}C$. The enzyme was protected from heat denature by the treatment of $Pb^#$, $Ba^#$, $Co^#$, $Zn^#$, and $Cu^#$, but was inactivated with $Hg^#$, $Fe^#$ strongly. Moreover, one of these metal ions, the cupper ion, has a strong protective activity on enzyme heat denature. And, it was not effected by treatment of EDTA.

• Journal of Distribution Science
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• v.15 no.1
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• pp.83-93
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• 2017

Purpose - After the transition, the development of defense industry in Eastern Europe has been regressed. Recently, they have internationally recognized that new products have been exported and contributed to the Innovation-Based Manufacturing of national economy such as unmanned reconnaissance aircraft, water purification technology, and mobile chemical laboratory, etc. The military forces in Eastern Europe are re-armed by the localization of self-produced munitions in their own defense industry, and then emphasize fostering their own defense industry. Thus, if they make a collaboration with other nations as a industrial cluster, it will gain a competitive edge on the defense industry. Research design, data, and methodology - The study was designed with the data of each national defense department. The research of the subject was reviewed before and after the transition. Thousands of workers have worked in defense industries before the transition, however, the defense industry and experts left after the transition. The Hungarian defense spending on GDP also dropped sharply from 1.72% in 2000 to 0.85% in 2013. But, due to the crisis in Ukraine and the crisis of Syrian refugees, the Viségrad Group (V4) member countries have also increased their interest in a defense and industries as well as the confidence in the EU and NATO. Results - On the whole, the joint of military training and purchase of defense materials were found in order to form the EU cooperative combat troops in CEE. There are the implementation of a joint manual plan for strengthening V4 security policy and the joint military exercises for V4 every year, and the others are electronic warfare and innovation of V4 national forces. Through such a performance analysis methodology, we found that the defense industry is developed through the national cluster cooperation among CEEs and spreading global distribution. Conclusions - Eastern Europe and Balkan countries have been looking forward to cooperating with the non-EU countries such as Korea and other defense industries. There are a lot of potential development into a new civilian cooperation defense industry for global-distribution. Thus, Korea should develop electronic commercial applications, not just as a weapon exporting region.

• Microbiology and Biotechnology Letters
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• v.20 no.5
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• pp.534-542
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• 1992

Trypsin inhibtor produced by Streptomyces sp. S-217 was purified by solvent extraction and various column chromatographies. and physico-chemical properties of the inhibitor were investigated. Inhibitor complex was formed for incubation of 10 min. Streptomyces 5-217 showed the highest production of trypsin inhibitor when it was cultivated at $37^{\circ}C$ for 66 hr in the medium containing 2% mannitol & 0.9% peptone, pH 7.0. Trypsin inhibitor was purified by column chromatography and high performance liquid chromatography. Trypsin inhibitor indicated the maxium wavelength at 215 nm and solubilities in water, methanol and dimethyl sulfoxide were 95, 70 and 75%, respectively. The concentration of 50% inhibition ($IC^{50}$) was 15 $\mu$g/ml. The inhibitor was stable on heating at $100^{\circ}C$ for 60 min in pH 5~9 and was more stable in alkaline region than acidic region.