• KSBB Journal
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• v.20 no.1 s.90
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• pp.66-70
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• 2005

Optimization of culture conditions for pigment production of Monascus purpureus P-57 mutant was investigated in liquid culture. The optimum composition of medium for the pigment production was $4\%$ rice power, $0.1\%$ beef extract, $0.03\%$ glutamic acid, $0.1\%\;MgSO_4{\cdot}7H_2O,\;0.25\%\;KH_2PO_4$, the optimum initial pH was 5.0. And the optimum culture conditions was at $30^{\circ}C$ for 8 days under 150 rpm with shaking. M. purpureus P-57 mutant produced the highest pigment as 356.04 units at red pigment and as 268.20 units at yellow pigment, and produced high cell mass as 15.00 g/L in liquid culture under the optimum conditions.

• Journal of Life Science
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• v.13 no.4
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• pp.492-497
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• 2003

This study was carried out to get the basic data for the mycelial growth of Lentinus lepideus in liquid culture. The optimal temperature and initial pH of mycelial growth of Lentinus lepideus were $25^{\circ}C$ and pH 5.5, respectively. The optimal medium was YMG medium. Among the carbon sources tested, glucose was effected to the mycelial growth and optimal glucose concentration was 4% (w/v). As nitrogen sources, malt extract and yeast extract appeared to be favorable and optimal malt extract and yeast extract [ratio (w/w) of 1:1] concentration was 1.5% (w/v).

• Analytical Science and Technology
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• v.13 no.1
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• pp.41-48
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• 2000

A biosensor for the determination of hydrogen peroxide was constructed by immobilizing of porcine small instestinal tissue in a plain carbon paste, and the effect of varying the $H_2O_2$ concentration and pH on the rate of catalytic reaction was evaluated. For the mathematical simplicity, no mediator was added. Electrochemical properties and the maximal rate could be derived from the quantitative analysis of the observed phenomena related to the electrode reaction. Also, pH dependence of the Michaelis constant enabled to calculate various thermodynamic parameters and subsequently to design a electrochemical method to determine the optimum pH of enzyme.

• Microbiology and Biotechnology Letters
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• v.20 no.6
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• pp.647-654
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• 1992

In order to study the physiological properties of the intestinal bacteria, we isolated the intestinal bacteria of Koreans and tested the enzymatic patterns. Isolated Bifidobacterium sp. Int-57 had the higher activity of $\alpha$-glucosidase, $\beta$-glucosidase, $\alpha$-galactosidase, $\beta$-galactosidase. $\beta$-xylosidase and $\alpha$-arabinofuranosidase than other intestinal microorganisms. The effect of the carbon sources on the production of each enzymes of Bijidobacterium sp. Int-57 was investigated. The most suitable carbon source for the production of $\beta$-glucosidase was maltose, for a-glucosidase cellobiose, for $\alpha$-galactosidase raffinose, for $\beta$-galactosidase lactose, and for $\beta$-xylosidase and $\alpha$-arabinofuranosidase xylose, respectively. In addition, we investigated the optimal conditions and pH stability of each crude enzymes. The optimal condition of a-glucosidase was pH 6.0 and $40^{\circ}C$. that of Jj-glucosidase pH 7.0 and 50oe, that of $\beta$-galactosidase pH 7.0 and $50^{\circ}C$, that of $\beta$-xylosidase pH 6.0 and $40^{\circ}C$ , and that of $\alpha$-arabinofuranosidase pH 5.0 and $50^{\circ}C$. respectively. a-Glucosidase was stable at pH 4.0-9.0. Jj-glucosidase at pH 4.0-7.0. $\beta$-galactosidase at pH 4.0-9.0, $\beta$-xylosidase at pH 4.0-6.0, and /3-arabinofuranosidase at pH 7.0-9.0, respectively.

• Applied Biological Chemistry
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• v.39 no.1
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• pp.60-66
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• 1996

To investigate a possible application of three strains of lactic acid bacteria(strain No. 49. No. 61. No. 75) from kimchi in milk fermentation industry, the optimal condition for production of intracellular ${\beta}-galactosidase$ from Lactobacillus(L.) plantarum and its enzymatic properties were examined. The preferable carbon source of the medium for strain No. 49 in production of ${\beta}-galactosidase$ was MRS broth with 1.0% lactose instead of dextrose of pH 65. for strain No. 75 with 1.0% galactose and for strain No. 61 with 3.0% lactose at pH 7.5, respectively. The maximum enzyme production from strain No. 49, No. 75 was observed after 48 hours culture at $30^{\circ}C$ in a medium containing the appropriate carbon source, from strain No. 61 after 48 hours culture at room temperature. The optimum temperature for ${\beta}-galactosidase$ activity from L. plantarum was $60^{\circ}C$ for strain No. 49, $37^{\circ}C$ for strain No. 61 and $50^{\circ}C$ for strain No. 75, respectively. The heat stability of enzyme activities for all three strains remained 90% at $45^{\circ}C$. The optimal pH was pH 6.5 and enzyme activities were most stable at pH for all three bacteria.

• KSBB Journal
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• v.10 no.3
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• pp.292-297
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• 1995

Studies on the production of Newcastle disease virus(NDV) were carried out to optimize culture conditions such as initial pH, temperature, serum concentration, multiplicity of infection(M.O.I.) as well as the addition of polycation, antioxidant, and DMSO. Initial pH from 7.2 to 8.1 showed little difference on NDV production but the initial pH below 6.8 resulted in the negative effect. The highest NDV titer was obtained at 0.1 M.O.I. In addition, the maximum production of virus was achieved at 2% FBS and optimum temperature was found to be $34^{\circ}C$. Treatment of polycoation increased the virus production. When ascorbic acid was added as an antioxidant, NDV production was also enhanced. Utilization of DMSO, a well-known permeabilizing agent, showed an inhibitory effect on the propagation of NDV.

• Journal of the Korean Chemical Society
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• v.48 no.6
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• pp.654-658
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• 2004

• Proceedings of the Plant Resources Society of Korea Conference
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• 2002.11b
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• pp.61-61
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• 2002

This study was excuted to decide the physiological characteristics of Kuehneromyces mutabilis. K. mutabilis was tested to select pertinent substract, temperature and pH range for the growth. Mycelial growth of K. mutabilis was mostly supported on MYPA among other tested synthetic or semi-synthetic media. The temperature range for pertinent mycelial growth was about 25~32$^{\circ}C$ and mostly stimulated at $25^{\circ}C$. And the pertinent pH range of MYPA was 5.0~6.0. The required carbon and nitrogen source for mycelial growth of K. mutabilis was tested. The mycelial growth was mostly stimulated by soluble starch at content. The carbon sources for pertinent mycelial growth was mannose or glucose. And the nitrogen source for pertinent mycelial growth was yeast extract or peptone.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.4
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• pp.620-624
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• 1997

The conditions for color intensity and electron donating ability to $\alpha$,$\alpha$-diphenyl-$\beta$- picryl-hydrazyl (DPPH) of Bacillus subtilis DC-2 were investigated. Temperature, pH and cultivation time were chosen as three factors, and the optimal conditions of color intensity and DPPH was determined with response surface methodology. Color intensity was affected by cultivation temperature(p<0.1). DPPH was influenced by cultivation temperature(p<0.05) and pH(p<0.1). But cultivation time was affected neither color in- tensity nor DPPH. Optimal conditions of color intensity with Bacillus subtilis DC-2 were appeared at cultivation temperature of 39.$25^{\circ}C$, pH 8.83 and cultivation time of 84.41hrs. Optimal conditions of DPPH with Bacillus subtilis DC-2 were revealed at cultivation temperature of 39.19$^{\circ}C$, pH 8.84 and cultivation time of 82.21hrs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2708-2712
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• 2010

Amines, ammonia or 3-methoxypropylamine (MPA), are used to maintain the optimized pH for the prevention of corrosion in the secondary side of Pressurized Water Reactors (PWRs). They are differently dissociated as a function of temperature which is not same in each location of the water-steam cycle. pH at the operation temperature depends on temperature of fluid and equilibrium constants of water and amines. Thus, every amine provides the different pH in the entire secondary side so that pH is not only the sufficient parameter in corrosion control. The secondary parameter, i.e., buffer intensity, is the ability to maintain a stable pH when $H^+$ are added or removed due to the ingress of impurities or the reaction of corrosion. The buffer intensity is necessary to provide the selection criteria for the best pH control agent for secondary side and the basic understanding of the reason why the flow-accelerated corrosion(FAC) rate may demonstrate the bell-shape curve over temperature. The buffer intensities of ammonia and MPA were reviewed over the entire operation temperature of PWRs. The sufficient buffer intensity is provided for the inhibition of corrosion by ammonia in low temperature $(25{\sim}100^{\circ}C)$ and by DMA in high temperature $(150{\sim}250^{\circ}C)$. In terms of buffer intensity, i) the best pH control agent is an amine with $pK_a(T)$ range of pH(T)- $1{\leq}pK_a(T){\leq}pH(T)$ + 0.5 and ii) the amine solution should have sufficient buffer intensity, ${\beta}$ to inhibit corrosion, and iii) FAC rate may be maximum at the temperature, where ${\beta}_B/{\beta}$ ratio is lowest.