• Applied Microscopy
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• 제11권1호
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• pp.29-38
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• 1981

Bacteriophage f2 were treated with ozone at various concentrations for 20 minutes. The inactivation kinetics of f2 phage were examined during ozonation. In order to study the mode of action of ozone on the phage f2, absorption of the phage to the host pili was meassured by utilyzing radioactivity of tritium incorporated into the phage RNA. Sucrose density gradient analysis and electron microscopy were also used to prove the mechanism of ozone inactivation of the phage. Strucural proteins of the phage were broken by ozonation into many protein subunits. The extent of phage breakage was proportional to ozone concentration and reaction time. Percent decrease of the phage absorption to the host pili was coincident with the rate of ozone inactivation of the phage. Ozone inactivation of bacteriophage f2 was shown to be caused by the breakage of the structural protein and blockage of the phage absorption to the host pili.

• 한국물환경학회지
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• 제25권1호
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• pp.136-141
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• 2009

Inactivation rates between enterococci and total coliforms were compared in order to find the suitability of enterococci as an indicator microorganism under various experiment conditions - freshwater and/or seawater, indoor and/or outdoor conditions. In case of indoor laboratory experiments, inactivation rates of enterococci ($k_D$: 0.050~0.082) were faster than those of total coliforms ($k_D$: 0.034~0.045) in freshwater matrix. In seawater matrix, however, survival rate of enterococci was longer than that of total coliforms at two out of three experiments in indoor condition. When incubated in outdoor conditions, enterococci were inactivated significantly more rapidly than total coliforms both in freshwater and seawater matrices. With these results, enterococci appear to be less suitable than total coliforms in terms of inactivation rates.

• 한국환경과학회지
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• 제24권9호
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• pp.1181-1188
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• 2015

In this study, we discussed about the application of the single physical and chemical treatment processes and the physical-chemical complex treatment processes on the inactivation of Artemia sp. in order to satisfy the USCG Phase II (United States Coast Guard). The results showed that initial disinfection rate of ultrasonic process in single batch process is higher than that of electrolysis. However, the inactivation rate showed slower than electrolysis. The inactivation rate of Artemia sp. on the single continuous treatment process ranked in the following order: homogenizer > electrolysis > ultrasonic process. Inactivation rate of Artemia sp. in continuous homogenizer-electrolysis complex process was reached at 100% immediately. A synergistic effect of ultrasonic-electrolytic complex process was found to be a small. The order of processes in a complex process did not affect the disinfection performance.

• Journal of Microbiology and Biotechnology
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• 제23권6호
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• pp.833-836
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• 2013

The inactivation of spores of Penicillium oxalicum by supercritical carbon dioxide ($SC-CO_2$) was optimized by response surface methodology. The optimal inactivation conditions of 16.8 MPa, $49^{\circ}C$, and 20 min were determined using ridge analysis, at which the predicted and experimental $log_{10}$ reductions were obtained as 5.74 and 6.12, respectively. The synergistic effect of a cosolvent (ethanol), which was used to modify $SC-CO_2$, on the inactivation of the fungal spores was investigated. At less severe conditions of 10 MPa and $40^{\circ}C$, P. oxalicum spores of $10^7$ CFU/ml were completely inactivated within 45 min by $SC-CO_2$ modified with ethanol.

• Journal of Ginseng Research
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• 제7권1호
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• pp.88-93
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• 1983

Studies were carried out to elucidate the protein stabilizing effect of ginseng. Malate dehydrogenase (EC 1.1.1.37) was used as a protein and the rate constant of the enzyme inactivation was determined under the heat denaturation condition. There was an optimum pH for the enzyme stability, the rate constant of the enzyme inactivation was minimum at BH 8.8. The rate constant was increased at lower and higher pH regions than the optimum pH. The inactivation reaction followed the Arrehnius law and the activation energy was measured as 36.8kcal/mole. The reaction rate was not affected by the enzyme concentration and thus it was assumed to be unimolecular first order reaction. The water extract of red ginseng decreased the rate constant of Malate dehydrogenate under heat inactivation condition to stabilize the enzyme activity. Purified ginseng saponin also stabilized the enzyme against heat inactivation.

• Archives of Pharmacal Research
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• 제5권2호
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• pp.45-52
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• 1982

Staibilization effect of Panax ginseng C. A. Meyer on .betha.-D-Galactosidase inactivation was proved by kinetic studies of thermal inactivation of the enzyme. The water extract Panax ginseng C. A. Meyer showed stabilization activity at minimal concentration of 10ppm. The methanolic extract was purified to obtain ginseng saponins, and two groups of the ginsenosides, i. e. protopanaxadiol and protopanaxatriol were isolated. They also showed a protective effect against the thermal and chemical inactivation of the enzyme; p-chloromercuribenzoic acid and hydroxylamine known as protein modifier greatly inactivated the enzyme but inactivation was significantly balocked by the ginseng component MG$^{2+}$, known as a cofactor, stabilized the enzyme and the poor stabilization effect by it was potentiated by ginseng components.s.

• 한국환경과학회지
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• 제23권3호
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• pp.369-378
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• 2014

Effect of improvement of the dielectric barrier discharge (DBD) plasma system on the inactivation performance of bacteria were investigated. The improvement of plasma reactor was performed by combination with the basic plasma reactor and UV process or combination with the basic plasma reactor and circulation system which was equipped with gas-liquid mixer. Experimental results showed that tailing effect was appeared after the exponential decrease in basic plasma reactor. There was no enhancement effect on the Ralstonia Solanacearum inactivation with combination of basic plasma process and UV process. The application of gas-liquid mixing device on the basic plasma reactor reduced inactivation time and led to complete sterilization. The effect existence of gas-liquid mixing device, voltage, air flow rate (1 ~ 5 L/min), water circulation rate (2.8 ~ 9.4 L/min) in gas-liquid mixing plasma, plasma voltage and UV power of gas-liquid mixing plasma+UV process were evaluated. The optimum air flow rate, water circulation rate, voltage of gas-liquid mixing system were 3 L/min, 3.5 L/min and 60 V, respectively. There was no enhancement effect on the Ralstonia Solanacearum inactivation with combination of gas-liquid mixing plasma and UV process.

• BMB Reports
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• 제28권2호
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• pp.124-128
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• 1995

Biodegradative threonine dehydratase purified from Serratia marcescens ATCC 25419 was inactivated by the arginine specific modification reagent, phenylglyoxal (PGO) and the lysine modification reagent, pyridoxal 5'-phosphate (PLP). The inactivation by PGO was protected by L-threonine and L-serine. The second order rate constant for the inactivation of the enzyme by PGO was calculated to be 136 $M^{-1}min^{-1}$. The reaction order with respect to PGO was 0.83. The inactivation of the enzyme by PGO was reversed upon addition of excess hydroxylamine. The inactivation of the enzyme by PLP was protected by L-threonine, L-serine, and a-aminobutyrate. The second order rate constant for the inactivation of the enzyme by PLP was 157 $M^{-1}min^{-1}$ and the order of reaction with respect to PLP was 1.0. The inactivation of the enzyme by PLP was reversed upon addition of excess acetic anhydride. Other chemical modification reagents such as N-ethylmaleimide, 5,5'-dithiobis (2-nitrobenzoate), iodoacetamide, sodium azide, phenylmethyl sulfonylfluoride and diethylpyrocarbonate had no effect on the enzyme activity. These results suggest that essential arginine and lysine residues may be located at or near the active site.

• 한국환경과학회지
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• 제23권5호
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• pp.985-993
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• 2014

For the field application of dielectric barrier discharge plasma reactor, a multi-plasma reactor was investigated for the inactivation of microorganisms in sewage. We also considered the possibility of degradation of non-biodegradable matter ($UV_{254}$) and total organic carbon (TOC) in sewage. The multi-plasma reactor in this study was divided into high voltage neon transformers, gas supply unit and three plasma modules (consist of discharge, ground electrode and quartz dielectric tube). The experimental results showed that the inactivation of microorganisms with treated water type ranked in the following order: distilled water > synthetic sewage effluent >> real sewage effluent. The dissolved various components in the real sewage effluent highly influenced the performance of the inactivation of microorganisms. After continuous plasma treatment for 10 min at 180 V, residual microorganisms appeared below 2 log and $UV_{254}$ absorbance (showing a non-biodegradable substance in water) and TOC removal rate were 27.5% and 8.5%, respectively. Therefore, when the sewage effluent is treated with plasma, it can be expected the inactivation of microorganisms and additional improvement of water quality. It was observed that the $NH_4{^+}$-N and $PO{_4}^{3-}$-P concentrations of sewage was kept at the constant plasma discharging for 30 min. On the other hand, $NO_3{^-}$-N concentration was increased with proceeding of the plasma discharge.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2003년도 Challenges and Achievements in Environmental Health
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• pp.140-143
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• 2003

This research was to determine and compare the inactivation of total coliform as the indicator organism with chlorine, chlorine dioxide and ozone for drinking water treatment. The inactivation of total coliform was experimentally analyzed for the dose of disinfectant, contact time, pH, Temperature and DOC. The experiments for the characterization of inactivation were performed in a series of batch processes with the total coliform as a general indicator organism based on chlorine, chlorine dioxide and ozone as disinfectants. The nearly 2.4, 3.0, 3.9 log inactivation of total coliform killed by injecting 1mg/L at 5 minutes for chlorine, chlorine dioxide and ozone. For the inactivation of 99.9%, Disinfectants required were 1.70, 1.00 and 0.60 mg/L for chlorine, chlorine dioxide and ozone, respectively. The bactericidal effects of disinfectants were decreased as the pH increased in the range of pH 6-9. The influence of pH change on the killing effect of chlorine dioxide was not strong, but that on ozone and free chlorine was sensitive. The bactericidal effects of the disinfectants were increased as the temperature increase. The activation energies were 36,053, 29,822, 24,906 J/mol of chlorine, chlorine dioxide, ozone for coliforms. The inactivation effects were shown in the lowest order of chlorine, chlorine dioxide and ozone.