• Microbiology and Biotechnology Letters
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• v.21 no.1
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• pp.23-29
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• 1993

A bacterial strain. producing a nucleoside oxidase was isolated from soil and identified as Flavobacterium meningosepticum by its taxonomical characteristics. The enzyme has been purified ISO-fold to electrophoretic homogeniety in an overall yield of 18% from the cell free extract of the producer. The enzyme catalyzed oxidation of only nucleosides related to both purine and pyrimidine with very high substrate specificity. The nucleoside oxidase was proved to be a noble enzyme by stoichiometry that 1 mol adenosine as a substrate was especially oxidized via adenosine 5' -aldehyde to 1 mol adenosine 5' -carboxylic acid with the formation of 2 mol $H_20_2$

• Microbiology and Biotechnology Letters
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• v.2 no.2
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• pp.63-77
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• 1974

The optimal operation problem of enzyme reactor of double inhibitions are dealt with Maximum Principle and Steepest Ascent Method. The operation policy of the intial concentration and amount of substrate, reaction time and the method of cross feed of substrate are determined in a system of reactor of constant volume add with cross feed of substrate. The policy for the soluble enzyme and the immobilized enzyme are greatly different from each other, and the performance index, the profit per unit time, of the latter are nearly twice greater than that of the former.

• Microbiology and Biotechnology Letters
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• v.18 no.1
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• pp.76-80
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• 1990

The production of extracellular soymilk clotting enzyme by Bacillus licheniformis strain 192, one of the soymilk clotting enzyme producers isolated formerly, was studied under various conditions. The medium composed of 1.5% potato starch, 2.0% soybean milk, 10% defatted soybean meal extract and 0.6% KH$_2$PO$_4$ (pH 6.1) was chosen as the most suitable medium and the culture at 35-4$0^{\circ}C$ for 3 days was most appropriate for the production of clotting enzyme.

• Microbiology and Biotechnology Letters
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• v.19 no.3
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• pp.281-289
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• 1991

Neurospora crassa (KCTC 6079) produces tyrosinase (EC 1.14.18.1) during sexual differentiation under derepressed conditions in the presence of inducers such as amino acid analogues, antimetabolites or protein synthesis inhibitors. The selection of inducer concentration and induction time as well as inducer type are critical for the optimization of the enzyme production. The best inducer was found to be cycloheximide. Since cycloheximide was toxic to the cells, an optimal inducer concentration and an optimal induction time were determined to maximize the enzyme production from batch cultures. Mathematical models for the cell growth and the enzyme production were proposed and used for process optimization. By optimizing the induction conditions, maximum tyrosinase productivity was increased significantly.

• Microbiology and Biotechnology Letters
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• v.16 no.6
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• pp.457-462
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• 1988

A potent actinomycetes strain was selected to digest raw starch, which was classified as a strain of Streptomyces sp.. Its amylase production was maximized when it was grown on wheat bran extract media added 4% of cooked corn starch and 0.16% of potassium nitrate for 6 days at 3$0^{\circ}C$ and initial pH 6.2.

• Microbiology and Biotechnology Letters
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• v.17 no.4
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• pp.313-320
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• 1989

Rhodotorula glutinis K-24 was found to produce internal, cell wall bound, and external invertase. Internal invertase was purified by column chromatographies on DEAE-Sephadex A-50, Sp-sephadex C-50, gel filtration on Sephadex G-200 and isoelectric focusing. Cell wall bound invertase was partially purified by the following procedures; column chromatography on DEAE-Sephadex A-50 and gel filtration on Sephadex G-100. Optimum pH and temperature for enzymatic activities of internal and cell wall bound invertase were pH 3.0 and 6$0^{\circ}C$, respectively. Both enzymes were inhibited by HgC1$_2$, AgNO$_3$, MnSO$_4$, and sodium dodecylsulfate. The molecular weights of internal and cell wall bound invertases were estimated to be 310,000 and 61,000, respectively. Other physicochemical properties of the both enzymes were similar.

• Microbiology and Biotechnology Letters
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• v.17 no.2
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• pp.148-153
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• 1989

A strain of alkalophilic Bacillus sp. YC-335 has been isolated from soil. The strain was capable of producing large amount of cyclodextrin glycosyl transferase (CGTase) in the culture broth. The preferable medium composition has been determined to be as follows : 1.5% soluble starch, 5% corn steep liquor, 0.1% $K_2$HPO$_4$, 0.02%mgSO$_4$.7$H_2O$, 1% CaCO$_3$and 1% Na$_2$CO$_3$(pH 10.3). The highest enzyme production was observed after 48 hours of cultivation at 31$^{\circ}C$. The optimum pH and temperature for the activity of crude enzyme were 6.0 and 5$0^{\circ}C$, respectively. The enzyme was stable between pH 5 and 9, and upto 5$0^{\circ}C$. The enzyme converted starch into $\alpha$-, $\beta$- and ${\gamma}$-CD in the relative amounts of 1:10:1.5, respectively.

• Microbiology and Biotechnology Letters
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• v.26 no.4
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• pp.345-351
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• 1998

In an effort to develop a potent system for the production of various dp (degree of polymerization) chitooligosaccharides, 32 enzymes or microbial systems were screened for chitosanolytic acitivity using chitosan as a substrate. The efficiency of each enzyme system was evaluated by the changes of turbidity and viscosity of chitosan solution, the amount of precipitate and the reducing sugar-producing activity in the enzymatic reaction mixture. Based on these assay methods for the chitosanase activity, Bacillus sp. P2l out of 32 screened systems showed highly potent endochitosanase, which was comparable with a commercially available enzyme (E7). Chitooligosaccharides of dp 3-7 were separated by TLC as major enzymatic reaction products, suggesting that the chitosanase from Bacillus sp. P2l be endo-splitting type.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.11 no.1
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• pp.27-32
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• 2011

최근 유전공학의 발달로 리소좀 축적 질환에서 효소 치료제가 개발되어 실제 치료에 사용되고 있다. 현재 효소 보충 치료가 가능한 리소좀 축적 질환에는 고셔병(Gaucher disease), 파브리병(Fabry disease), 폼페병(Pompe disease), 뮤코다당체침착병(Mucopolysaccharidosis, MPS) 1형, 2형, 6형이 있으며 비교적 안전하면서 증상 완화에도 효과적으로 보인다. 그러나 이미 진행이 된 증상에 대해서는 비가역적이므로 조기에 진단을 하여 치료를 시작하는 것이 중요하다. 효소 보충 치료의 장기간에 걸친 치료 효과에 대해서 지속적인 평가가 필요하며 무엇보다 뼈와 중추신경계에 대한 효과는 제한적이므로 이에 대한 새로운 치료법의 개발이 필요하다.

• 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.