• The Microorganisms and Industry
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• v.17 no.2
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• pp.22-27
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• 1991

본 논문에서는 무증자 생전분을 기질로 한 분쇄마찰매체 함유 효소 반응계에서의 여러 maltose 생산효소를 이용한 고농도, 고순도 maltose 제조에 관하여 기술함으로서 새로운 maltose 제조공정을 소개하고자 한다.

• KSBB Journal
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• v.16 no.4
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• pp.321-326
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• 2001

The change of molecular weight inside and outside a capsule produced using coencapsulating technology was investigated. Chitosan and chitosanase were enveloped in this membrane and product released was a loaded the medium by the principle of size exclusion. The leakage of substrate corresponding to the agitation speed was controlled by adjusting the alginate and CaCO$_3$ concentrations. The optimal condition of alginate concentration and agitation speed were 0.5% and 40rpm, respectively. Membrane thickness and capsules diameter were 10 $\mu$m and approx. 3.0 - 1.5 mm, respectively. Molecular weight difference by concentration and alginate viscosity were of little significance. In accordance with the molecular weight distribution versus enzyme concentration relationship, low concentration of enzyme produced high molecular weight oligosaccharides. At a 1.5 mm capsule size the product diffusion rate to outer surface highest. The molecular weight distribution of the released oligosaccharides was ranged from 1000 to 6000 Da. More than 80% of the initial activity of encapsulated enzyme retained after 8hrs of reaction.

• KSBB Journal
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• v.22 no.1
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• pp.43-47
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• 2007

The effect of surfactant on the hydrolysis of used newspaper was investigated. The most suitable surfactant for the pretreatment stage was found to be NP-series surfactants among 9 kinds of non ionic surfactants. Process parameters such as surfactant concentration, mixing speed, pretreatment temperature and time were tested to optimize for maximum digestibility and 0.5%, 100rpm, 30$^{\circ}C$, and 1 h were found to be optimum, respectively. In order to maximize digestibility, substrate was pretreated with NP-20 and then the pretreated substrate was hydrolyzed by adding TW-80. The effect of surfactant on the hydrolysis of previously surfactant-pretreated newspaper was marginal. Therefore, the digestibility with the addition order of enzyme and surfactant was investigated by using surfactant only in hydrolysis stage. The results show that digestibility was more lowered as the surfactant addition after adding enzyme to substrate was more delayed.

• Journal of Life Science
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• v.12 no.1
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• pp.32-42
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• 2002

It was researched to react horse serum-BChE with hefanoylthiocholine chosen among choline esters. According as number of carbon of acyl group in choline esters was increased, reactivity was decreased but strength of ES complex was increased (Km=0,140mM). The pH-V/K profile for BChE-catalyzed hydrolysis of hexanoylthiocholine yields a p $K_{a}$ =4.974$\pm$0.028. This value is equal to recent literature that shows systematic shift from dependence of activity on the basic form fo a residue that huts a p $K_{a}$ =6.2~6.4 to catalysis by a residue or residues that has a p $K_{a}$ =4.7~5.0. The resulting kinetic solvent isotope effect of hexanoylthiocholine is $^{D/V}$K=1.18. The magnitude of the isotope effect suggests that proton transfer is not an element of transition-state stabilization.n.

• Food Engineering Progress
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• v.15 no.3
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• pp.214-220
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• 2011

$\beta$-Glucosidase enzyme reaction under high hydrostatic pressure was investigated in terms of physical chemistry. A model substrate (p-nitrophenyl-${\beta}$-D-glucopyranoside(pNPG)) was used, and the pressure effects on the enzymatic hydrolysis (pNPG${\rightarrow}$pNP) at 25 MPa, 50 MPa, 75 MPa, and 100 MPa were analyzed. Two parts of the reaction such as kinetic and equilibrium stages were considered for mathematical modelling, and their physicochemical parameters such as forward and inverse reaction constants, equilibrium constant, volume change by pressure, etc. were mathematically modeled. The product concentration increased with pressure, and the two stages of reaction were observed. Prediction models were derived to numerically compute the product concentrations according to reaction time over kinetic to equilibrium stages under high pressure condition. Conclusively, the $\beta$-Glucosidase enzyme reaction could be activated by pressurization within 100 MPa, and the developed models were very successful in their prediction.

• KSBB Journal
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• v.4 no.3
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• pp.215-220
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• 1989

To develop an attrition coupled enzyme reactor with high efficiency-low energy consumption for saccharification of insoluble biomass, a 5L horizontal paddle type bioreactor was constructed and its performance was evaluated. The optimal condition for saccharification of 50g $\alpha$ -cellulose/L was found to be 200rpm with 500g of 3mm glass bead. Especially, the horizontal paddle type bloreactor was very effective for saccharification of high concentration of insoluble cellulose, in which around 72% of $\alpha$ -cellulose was saccharified for 75g $\alpha$ -cellulose/L, and even up to 70% for 100g of $\alpha$ -cellulose/L after 24hours. Under the optimal condition, the power consumption was measured to be around 1.7watth/g. Horizontal paddle type bioreactor seems to have an appropriated structural feature for industrial scale operation and to be an effective and energy saving attrition coupled enzyme reactor.

• Journal of Life Science
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• v.13 no.6
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• pp.788-793
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• 2003

Production of chiral phenyl oxirane by Rhodosporidium toruloides SJ-4 was investigated. Racemic phenyl oxirane was kinetically resolved by enantioselective hydrolysis reaction by epoxide hydrolase of R. toruloides in two-phase hollow-fiber reactor system. Dodecane with high concentration of the racemic substrate passed through the lumen side and cell suspension was recirculated through the shell side of the hollow fiber reactor For the removal of phenyl-1, 2-ethandiol to reduce the product inhibition to biocatalysts, another hollow-fiber reactor was employed to extract the diol. Racemic phenyl oxirane up to 300 mM was enantioselectively resolved with high enantiopurity (>99% ee) in hollow-fiber reactor system.

• Journal of the Korean GEO-environmental Society
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• v.15 no.5
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• pp.39-46
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• 2014

The objectives of this study were to determine biodegradation and characteristics of BTEX and MTBE under aerovic-anaerobic conditions and evaluate the potential of natural attenuation method in denitrifying condition.. In the single-substrate experiments, all of the BTEX compounds were degraded under all the conditions. but, lower degradation of benzene and p-xylene were observed under aerobic condition due to the lack of oxygen initially supplied. In the mixed-substrate experiments, BTEX degradation was delayed compared to that in the single-substrate experiments due to a competition of the substrates. Biodegradation of MTBE was observed only under denitrifying conditions and we expected that MTBE mineralized to $CO_2$ without the accumulation of TBA. We also conducted to determine the effect of initial nitrate concentration on BTEX and MTBE degradation. At low nitrate concentration (<50 mg/L), BTEX degradations were limited by the lack of electron acceptor and BTEX degradation was inhibited at high nitrate concentration (>200 mg/L). The results in this study indicated that biotransformation could be applied to the gasoline-contaminated region under aerovic-anaerobic.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.662-665
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• 2001

Enantioselective production of levofloxacin from ofloxacin butyl ester by porcine liver esterase was enhanced with the addition of ${\alpha}$-cyclodextrin(${\alpha}-CD$) and pH change. The conversion yield was increased from 27 to 64% and 100% with 150 mM substrate when the molar ratio of ${\alpha}-CD$ to substrate was 1 and 2, respectively. When 100 mM of substrate was added with the same molar ratio of ${\alpha}-CD$ at pH 5.6, the solubility was increased 3.8 times and the conversion yield was increased 4.4 times.

• Biomedical Science Letters
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• v.6 no.3
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• pp.181-186
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• 2000

Asadisulphide were purified from Ferrula assafoetida by organic solvent extraction and chromatography. Its inhibitory effects on the TPA-induced adherence of HL-60 cells was analyzed. Since ethyl acetate extracts of F. assafoetida has the strongest inhibitory effect on adherence of HL-60 cells, it was re-extracted with ethyl acetate, hexane, and ethyl ether and chromatographed three times to isolate asadisulphide. At the minimum concentration of 2 $\mu\textrm{g}$/ml, asadisulphide inhibited adherence of 98% of HL-60 cells that have been treated with TPA. It also showed anti-cancer effect with no cytotoxity in the ED$_{50}$ value of 20 $\mu\textrm{g}$/ml.