• Applied Science and Convergence Technology
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• 제26권6호
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• pp.157-163
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• 2017

Immobilized enzymes have become the subject of considerable interest due to their excellent functional properties such as reusability, cost-effectiveness, and optimality during the past decades. Enzyme immobilization technology is not only used in industrial processes, but also a component technology of products for medical diagnostics, therapy, food industry, bio energy, and biomaterial detection. In this review, new methods for enzyme immobilization are introduced, and the advantages and disadvantages of a variety of techniques in enzyme immobilization will be also discussed.

• Journal of Applied Biological Chemistry
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• 제66권
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• pp.512-518
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• 2023

To address inherent weaknesses such as low mechanical strength and limited enzyme loading capacity in conventional chitosan or alginate beads, an additional step involving the exchange of anionic surfactants with hydroxide ions was employed to prepare porous chitosan hydrogel capsules for enzyme immobilization. Consequently, excellent thermal stability and long-term storage stability were confirmed. Furthermore, coating the porous chitosan hydrogel capsules with polydopamine not only improved mechanical stability but also exhibited remarkable enzyme immobilization efficiency (97.6% for M1-D0.5). Additionally, it was demonstrated that the scope of application for chitosan hydrogel beads, prepared using conventional methods, could be further expanded by introducing an additional step of polydopamine coating. The enzyme immobilization matrix developed in this study can be selectively applied to suit specific purposes and is expected to be utilized as a support for the adsorption or covalent binding of various substances.

• BMB Reports
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• 제44권2호
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• pp.87-95
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• 2011

Enzymatic catalysis has been pursued extensively in a wide range of important chemical processes for their unparalleled selectivity and mild reaction conditions. However, enzymes are usually costly and easy to inactivate in their free forms. Immobilization is the key to optimizing the in-service performance of an enzyme in industrial processes, particularly in the field of non-aqueous phase catalysis. Since the immobilization process for enzymes will inevitably result in some loss of activity, improving the activity retention of the immobilized enzyme is critical. To some extent, the performance of an immobilized enzyme is mainly governed by the supports used for immobilization, thus it is important to fully understand the properties of supporting materials and immobilization processes. In recent years, there has been growing concern in using polymeric materials as supports for their good mechanical and easily adjustable properties. Furthermore, a great many work has been done in order to improve the activity retention and stabilities of immobilized enzymes. Some introduce a spacer arm onto the support surface to improve the enzyme mobility. The support surface is also modified towards biocompatibility to reduce non-biospecific interactions between the enzyme and support. Besides, natural materials can be used directly as supporting materials owning to their inert and biocompatible properties. This review is focused on recent advances in using polymeric materials as hosts for lipase immobilization by two different methods, surface attachment and encapsulation. Polymeric materials of different forms, such as particles, membranes and nanofibers, are discussed in detail. The prospective applications of immobilized enzymes, especially the enzyme-immobilized membrane bioreactors (EMBR) are also discussed.

• 한국미생물·생명공학회지
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• 제19권1호
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• pp.100-108
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• 1991

Molecular characteristics and improving methods for thermal stability of enzyme have been considered. Intrinsic and extrinsic stabilizing mechanisms are two governing principles for enhanced thermal stability of enzyme in molecular basis. Factors contributing to the former and the latter mechanisms may be involved in the enhanced thermal stability of enzyme complementarily. Also, the methods for improving thermal stability of enzyme which comprise reaction in organic solvent system, chemical modification, immobilization, sequential unfolding and refolding, gene manipulation techniques and enzyme-antibody complexing are reviewed.

• KSBB Journal
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• 제18권4호
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• pp.306-311
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• 2003

융합단백질의 절단을 위해 EK를 고정화하여 액상 절단반응과 같은 80％의 절단수율을 얻을 수 있었다. 그리고 니켈 친화칼럼을 이용하여 간단한 정제공정을 구축하였다. 공유결합한 EK의 경우 니켈친화 결합한 EK보다 높은 재접힘 수율을 나타내었고 풀림과 재접힘을 이용하여 효소의 초기 활성을 회복함에 따라서 반복사용을 통한 경제적인 절단공정을 구축할 수 있게 되었다. 그러나 고정화 과정에서 효소의 활성이 감소하는 문제점과 고정화 수율을 높이기 위한 연구가 필요하다.

• Current Research on Agriculture and Life Sciences
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• 제3권
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• pp.166-173
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• 1985

��신을 DEAE-cellulose, CM-cellulose, Sepharose-4B와 porous glass beads을 사용(使用)하여 고정화(固定化)시켰던 바 그 결과(結果)를 요약(要約)하면 다음과 같다. 1. CM cellulose와 DEAE-cellulose의 ��신 흡착량(吸着量)은 건조된 bead 1 gr에 대하여 각각 10 mg와 15 mg이었고 glutaralde을 사용(使用)함으로서 20 mg와 27 mg로 흡착량(吸着量)이 증가(增加)하였고 효소(酵素)의 활력(活力)은 용해성효소(溶解性酵素)에 비해 각각 22%, 24%로 나타났다. 2. Sepharose-4B을 cyanogen bromide을 사용(使用)하여 활성화(活性化)시킨후 glutaraldehyde을 사용(使用)하여 공유결합을 유도하였던 바 건조된 bead 1 gr에 ��신 19 mg가 통합(統合)되었고 효소(酵素)의 활력(活力)은 23%로 나타났다. 3. Porous glass beads의 표면(表面)을 succineamido - propyl glass beads의 형태(形態)로 유도체를 만든후 ��신을 고정화(固定化)시켰을 때 bead 1 gr가 ��신 40 mg을 통합(統合)할 수 있었고 효소(酵素)의 활력(活力)은 용해성효소(溶解性酵素)에 비해 45%로 나타났다.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 1978년도 춘계학술대회
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• pp.96.2-96
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• 1978

Commerial naringinase from Aspergillus niger was partially purified by various methods, and was immobilized to porous alkylamine silica of 30~40 mesh and 400 $\AA\pm10％$ pore diameter that had been activated with 2.5％ glutaraldehyde. About 50~70％ of initial naringinase activity was recovered after the immobilization process. Some enzymatic properties of the immobilized naringinase was investigated and compared with those of the native enzyme. The optimal temper-ature had moved from $40^{\circ}C$ to $55^{\circ}C$ and the heat stability of the immobilized enzyme was better than that of the native naringinase. But no signi-ficant diference in the pH effect on activity was detected. The activation energy of reaction, Ea, was markedly decreased from 14.9 to 8.64 (Kcal/mole) by immobilization.

• Journal of the Korean Wood Science and Technology
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• 제29권3호
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• pp.104-111
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• 2001

There are some evidence that active enzymatic proteins, e.g. fungal laccase, exist in the naturally occured soil humus. This study was performed to investigate the covalent binding of fungal laccase to the humic acid-iron complex, and to measure laccase activity of immobilized ones. Seven methods were adopted to form the covalent binding of fungal laccase with soil humic acids complexed with iron. Using these seven methods it was possible to change the dimension of spacer arm between laccase and support, and also to regulate the mode of covalent binding of this enzyme. The spacer arm was regulated from 2C to 11C. There was not observed any straight relationship between the spacer arm longitude and the laccase activity after immobilization, but the binding mode more effective than the former. Three out of the seven methods gave the high activity of immobilized laccase, and which active products of laccase immobilization was stable up to 10 days after the process. It is indicated that natural soil condition might be prevented the laccase activation by the toxic influence of some phenolic humic compounds. It was shown, for the first time, the possibilities to obtain the high activity of fungal laccase by binding to humic acids, and especially in complex with iron.

• 한국미생물·생명공학회지
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• 제18권1호
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• pp.56-60
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• 1990

Brevibacterium sp. CH1 균주가 흙으로부터 분리하여 아크릴로니트릴을 아크릴아마이드로 생변화를 수행하는데 필요한 효소를 생산하기 위하여 사용하였다. 여러가지 고정화 방법과 효소 안정성이 조사 되었다. Nitrile hydratase는 free cell에 대하여 pH7에서 최대한 안정성을 보여주었다. EDTA와 phenyl menthl fluoride을 protease inhibitor로 선정하여 inhibitor 농도를 변화시키면서 효소의 저장안정성을 평가하였다. 아크릴아마이드가 안정성 및 물리화학적 강도를 고려 할 때 가장 좋은 carrier였다. 고정화 세포의 저장안정성은 4$^{\circ}C$에서 gel상의 아크릴아마이드 농도가 증가함에 따라 감소하였고, 25% 이상의 아크릴아마이드 농도에서 안정성이 매우 낮았다.

• Journal of Electrochemical Science and Technology
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• 제8권2호
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• pp.87-95
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• 2017

Enzymatic fuel cells are promising low cost, compact and flexible energy resources. The basis of enzymatic fuel cells is transfer of electron from enzyme to the electrode surface and vice versa. Electron transfer is done either by direct or mediated electron transfer (DET/MET), each one having its own advantages and disadvantages. In this study, the DET and MET of laccase-based biocathodes are compared with each other. The DET of laccase enzyme has been studied using two methods; assemble of needle-like carbon nanotubes (CNTs) on the electrode, and CNTs/Nafion polymer. MET of laccase enzyme also is done by use of ceramic electrode containing, ABTS (2,2'-azino-bis [3-ethylbenzthiazoline-6-sulphonic acid]) /sol-gel. Cyclic voltammetric results of DET showed a pair of well-defined redox peaks at $200{\mu}A$ and $170{\mu}A$ in a solution containing 5and $10{\mu}M$ o-dianisidine as a substrate for needle-like assembled CNTs and CNTs-Nafion composite respectively. In MET method using sol-gel/ABTS, the maximum redox peak was $14{\mu}A$ in the presence of 15 M solution o-dianisidine as substrate. The cyclic voltammetric results showed that laccase immobilization on needle-like assembled CNTs or CNTs-Nafion is more efficient than the sol-gel/ABTS electrode. Therefore, the expressed methods can be used to fabricate biocathode of biofuel cells or laccase based biosensors.