• 한국환경보건학회지
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• 제23권3호
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• pp.1-6
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• 1997

This research was conducted in the laboratory to investigate an alternative of Copper(Cu) removal from an heavymetal wastewater using the electrochemical precipitation(ECP) process. The ECP unit consisted of an electrolytic cell made of Titanium plate and Steel plate representing anode and cathode. The DC power source applied to the ECP unit had electrical potential(E) of 50$\pm$ 1V, respectively. The synthetic wastewater used in the experiments contained Cu in the 10 mg/l concentration and the electrode separation were 2, 3, 4 cm and the initial pH were 3, 6, 9, 12, and electrolytic concentration were 0.005, 0.0125, 0.025, 0.0375 mole, and the real heavymetal wastewater used in the experiments. From the experiment for removal efficiency according to pH variation, the low pH area doesn't give the coagulation effect by Ti(OH)$_4$ because process interfere with the coagulation and oxidation reaction, therefore the optimum pH was 4-7. The removal rate was 97.75% after the lapse of 30 minutes when copper concentration and electrolytic concentration were respectively 10 mg/l and 0.025 mole. The removal rate was 96.41% after the lapse of 30minutes when the real heavymetal wastewater used. The optimum consumption of power showed 27KWh/m$^3$ when copper concentration, electrolyte concentration and cell potential were respectively 10 mg/l, 0.025 mole and 50$\pm$ 1 Volt.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.640-643
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• 2000

본 연구는 항산화작용, 항암작용, estrogen 유사작용, 항골다공증작용 등 다양한 생리적기능을 가진 isoflavones에 대한 추출조건을 추출용매의 농도, 추출온도, 추출pH, 추출시간으로 나누어 단계적으로 isoflavones을 추출하는 실험을 실시하였고, 보다 기능이 잘 알려진 4종 isoflavones 추출에 대한 결과를 분석하여 최적추출 조건을 선정하였다. 그 결과 75% ethanol, $80^{\circ}C$, pH4, 3시간의 추출 조건에서 $4,024{\mu}g/ml$의 가장 높은 총 isoflavones 추출량을 나타내었고, 대두 추출물 중의 단백질 제거를 위해 이용된 염화칼슘의 농도가 증가할수록 보다 높은 함량의 isoflavones을 얻을 수 있었다.

• 한국의류학회지
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• 제28권3_4호
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• pp.444-451
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• 2004

This study was carried out to investigate the chemical and dyeing properties of Petasites japonicus leaf extract under the various extracting and dyeing conditions such as temperature, time, the ratio of water and pH, repetition of dyeing in silk and cotton fabrics with Petasites japonicus leaf. The results were as follows: 1. It was found that λ$_{\max}$ of color solution extracted by Petasites japonicus leaf has two peaks at 290nm and 323nm. 2. The optimum extracting conditions were studied at 10$0^{\circ}C$, 40min., pH 7 and 1 : 20(the ratio of water and Petasites japonicus leaf), the optimum dyeing temperature, dyeing time, dyeing pH and repetition of dyeing were 10$0^{\circ}C$, 60min., pH 7, repetitions of three times, respectively. 3. Silk and cotton fabrics dyed with Petasites japonicus leaf extract were colored yellowish orange. The colory Petasites japonicus leaf extract in silk and cotton fabrics were deeped by same-mordanting with aluminum potassium sufate and cupric sulfate. 4. Washing fastness of silk fabrics was 4∼5 grade, but cotton fabrics was 3∼4 grade, so washing fastness of silk fabrics washed with neutral detergent was excellent.

• 한국환경보건학회지
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• 제34권3호
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• pp.226-232
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• 2008

A feasibility study for the application of the photoelectrocatalytic decolorization of Rhodamine B (RhB) was performed in a photoelectrochemical reactor with immobilized $TiO_2$ particle. The effects of operating conditions, such as current, electrolyte and pH were evaluated. The experimental results showed that optimum $TiO_2$ dosage and current in the photoelectrocatalytic process were 83.3 g/l and 0.5 A, respectively. It was found that the RhB could be degraded more efficiently by this photoelectrocatalytic process than the sum of the two individual oxidation processes (photocatalytic and electrolytic process). The addition of NaCl increased the initial decolorization rate and reduced reaction time. The optimum dosage of NaCl was 0.15 g/l. The decolorization rate of the photoelectrocatalytic process increased sharply with a decrease in pH value. However when the NaCl was added, the pH effect was not high.

• 한국물환경학회지
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• 제27권2호
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• pp.194-199
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• 2011

This study has been carried out to evaluate the performance of $PbO_2$ electrode for the purpose of degradation of N,N-Dimethyl-4-nitrosoaniline (RNO, indicator of OH radical), generation of ozone and decolorization of Rhodamine B (RhB) in water. The effect of the applied current (0.2~1.2 A), electrolyte type (NaCl, KCl and $Na_2SO_4$), electrolyte concentration (0.0~2.5 g/L) and solution pH (3~11) were evaluated. Experimental results showed that RhB and RNO removal were increased with the increase of current, NaCl dosage and decrease of pH. Ozone generation tendencies appeared with the almost similar to the RhB and RNO degradation, except of solution pH (Ozone generation was increased with increase of pH). Optimum current for RhB degradation and consumption of electric power was 1.0 A. The RhB degradation with Cl type electrolyte were higher than that with the sulfate type. Optimum NaCl dosage for RhB degradation was 1.0 g/L.

• Journal of Microbiology and Biotechnology
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• 제34권5호
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• pp.1119-1125
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• 2024

Phytase increases the availability of phosphate and trace elements by hydrolyzing the phosphomonoester bond in phytate present in animal feed. It is also an important enzyme from an environmental perspective because it not only promotes the growth of livestocks but also prevents phosphorus contamination released into the environment. Here we present a novel phytase derived from Turicimonas muris, TmPhy, which has distinctive structure and properties compared to other previously known phytases. TmPhy gene expressed in the Pichia system was confirmed to be 41 kDa in size and was used in purified form to evaluate optimal conditions for maximum activity. TmPhy has a dual optimum pH at pH3 and pH6.8 and exhibited the highest activity at 70℃. However, the heat tolerance of the wildtype was not satisfactory for feed application. Therefore, random mutation, disulfide bond introduction, and N-terminal mutation were performed to improve the thermostability of the TmPhy. Random mutation resulted in TmPhyM with about 45% improvement in stability at 60℃. Through further improvements, a total of three mutants were screened and their heat tolerance was evaluated. As a result, we obtained TmPhyMD1 with 46.5% residual activity, TmPhyMD2 with 74.1%, and TmPhyMD3 with 66.8% at 80℃ heat treatment without significant loss of or with increased activity.

• 대한화학회지
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• 제49권3호
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• pp.325-328
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• 2005

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2006년도 춘계학술발표논문집
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• pp.184-187
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• 2006

Nickel was plated electrolessly on 304L stainless steel powder. To obtain uniform coating and dispension of powder, the bath was continuously agitated with magnetic stirrer. The various pH and bath temperatures were studied. The conditions were in the range of $pH4{\sim}10$ and $45{\sim}65^{\circ}C$, respectively. The coating morphologies were examined by SEM/EDS tests. The optimum condition was pH9 at $55^{\circ}C$.

• 한국식생활문화학회지
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• 제5권4호
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• pp.443-448
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• 1990

The object of this study was to investigate the characteristics of pectinesterase(PE), polygalacturonase(PG) and Peroxidase(POD) in Kimchi materials. The results were as follows : 1. The specific activities of PEs in Korean cabbage, Korean raddish, garlic and ginger were 200 unit/mg protein, 23.1 unit/mg protein, 0.8 unit/mg protein and 32 unit/mg protein, respectively. The optimum pHs of PEs in all materials were between 7 to 8. The concentrations of NaCl, $CaCl_2$ which showed the highest activities of PEs were $0.2{\sim}0.3M$ NaCl, 50 mM $CaCl_2$ in Korean cabbage and raddish, 0.05 M NaCl, 20 mM $CaCl_2$ in garlic and 0.2 M NaCl, 20 mM $CaCl_2$ in ginger. 2. The specific activities and the optimum pHs of PGs were 1.5 unit/mg protein and pH 4.5 in Korean cabbage, 1.6 unit/mg protein and $pH\;4.5{\sim}5.5M$ in Korean raddish, 0.06 unit/mg protein and $pH\;3.0{\sim}3.5M$ in garlic, and 0.06 unit/mg protein and $CaCl_2$ in ginger. The concentrations of NaCl, $CaCl_2$ which showed the highest activities of PGs were $0.1{\sim}0.2M$ NaCl and $0.15{\sim}0.2mM$ mM $CaCl_2$ in all materials. 3. The specific activities and the optimum pHs of PODs in Korean cabbage, Korean raddish, garlic and ginger were 71.3 unit/mg protein ; pH 6.0. 769 unit/mg protein ; pH 5.5, 1.09 unit/mg protein ; pH 4.5 and 12.7 unit/mg protein ; $pH\;5.0{\sim}5.5M$, respectively. POD activities were not decreased in Korean cabbage, but decreased in Korean raddish by the increase of NaCl, $CaCl_2$ concentrations. In garlic and ginger, POD activities were a little slightly affected by the increase of NaCl, $CaCl_2$ concentrations.

• Journal of Microbiology and Biotechnology
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• 제22권2호
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• pp.220-225
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• 2012

In batch culture for Poly(vinyl alcohol) (PVA)-degrading enzyme (PVAase) production by a mixed culture, higher pH (pH 7.5) was favorable for PVAase production at the prophase of cultivation, but lower pH (pH 7.0) was favorable at the anaphase. This situation was caused by the fact that the optimum pH for different key enzymes [PVA dehydrogenase (PVADH) and oxidized PVA hydrolase (OPH)] production is various. The activity and average specific production rate of PVADH reached the highest values at constant pH 7.5, whereas those of OPH appeared at pH 7.0. A two-stage pH control strategy was therefore developed and compared for its potential in improving PVAase production. By using this strategy, the maximal PVAase activity reached 2.05 U/ml, which increased by 15.2% and 24.2% over the fermentation at constant pH 7.5 and 7.0.