• Journal of Electrochemical Science and Technology
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• 제2권2호
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• pp.124-129
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• 2011

A simple process of fabricating micropillar structure and its influence upon enhancing electrochemical biosensor response were studied in this work. Conducting polymer PEDOT was used as a base material in formulating a composite with PVA. Micro porous PC membrane filter was used as a template for the micropillar of the composite on ITO electrode. This structure could provide plenty of encapsulating space for enzyme species. After dosing enzyme solution into this space, Nafion film tent was cast over the pillar structure to complete the micropillar cavity structure. In this way, the encapsulation of enzyme could be accomplished without any chemical modification. The amount of enzyme species was easily controllable by varying the concentration of the dosing solution. The more amount of enzyme is stored in the sensor, the higher the electrochemical response is produced. One more reason for the sensitivity improvement comes from the large surface area of the micropillar structure. Application of 0.7 V produced the best current response under the condition of pH 7.4. This biosensor showed linear response to the glucose in 0.1~1 mM range with the average sensitivity of $14.06{\mu}A/mMcm^2$. Detection limit was 0.01 mM based on S/N = 3.

• 한국미생물·생명공학회지
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• 제48권1호
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• pp.12-23
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• 2020

Edible films containing antimicrobial agents can be used as safe alternatives to preserve food products. Essential oils are well-recognized antimicrobials. However, their low water solubility, volatility and high sensitivity to oxygen and light limit their application in food preservation. These limitations could be overcome by embedding these essential oils in complexed product matrices exploiting the encapsulation efficiency of β-cyclodextrin. This study focused on the maximization of β-cyclodextrin production using cyclodextrin glucanotransferase (CGTase) and the evaluation of its encapsulation efficacy to fabricate edible antimicrobial films. Response surface methodology (RSM) was used to optimize CGTase production by Brevibacillus brevis AMI-2 isolated from mangrove sediments. This enzyme was partially purified using a starch adsorption method and entrapped in calcium alginate. Cyclodextrin produced by the immobilized enzyme was then confirmed using high performance thin layer chromatography, and its encapsulation efficiency was investigated. The clove oil/β-cyclodextrin inclusion complexes were prepared using the coprecipitation method, and incorporated into chitosan films, and subjected to antimicrobial testing. Results revealed that β-cyclodextrin was produced as a major product of the enzymatic reaction. In addition, the incorporation of clove oil/β-cyclodextrin inclusion complexes significantly increased the antimicrobial activity of chitosan films against Staphylococcus aureus, Staphylococcus epidermidis, Salmonella Typhimurium, Escherichia coli, and Candida albicans. In conclusion, B. brevis AMI-2 is a promising source for CGTase to synthesize β-cyclodextrin with considerable encapsulation efficiency. Further, the obtained results suggest that chitosan films containing clove oils encapsulated in β-cyclodextrin could serve as edible antimicrobial food-packaging materials to combat microbial contamination.

• 대한화장품학회지
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• 제33권2호
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• pp.93-97
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• 2007

일반적으로 음이온 계면활성제는 효소의 disulfide bond를 분해시켜 효소의 활성이 없어진다. 따라서 특정한 캡슐에 효소를 포집하여 안정도를 증대시킨다. 본 연구에서는 polyethylene glycol (PEG), polypropylene glycol (PPG), 그리고 PEG-PPG-PEG block copolymer 등의 폴리올을 이용하여 papain 효소의 안정도를 증대시켰다. Energy dispersive spectroscopy (EDS)와 confocal laser scanning microscope (CLSM) 분석을 통하여 폴리올은 고분자층과 효소의 중간에 위치하며, 이들은 완충액으로 작용하여 효소의 안정도를 증대시키는 것으로 확인하였다. 또한, 이온 복합체를 이용하여 다층 캡슐을 제조하여 wash-off 형태의 세정제에 응용하였다. 세정제 내에서 계면활성제와 물은 효소캡슐의 표면에 분산되었으며, 캡슐의 중앙부분으로 서서히 침투되었다. 반면에 본 연구에서 사용된 sodium lauroyl sarcosinate와 polyguaternium-6는 물이 효소부분으로 침투하지 않는 것을 in vivo 시험을 통하여 확인하였다.

• Journal of Pharmaceutical Investigation
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• 제22권1호
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• pp.1-10
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• 1992

The use of erythrocyte as drug carrier has been reviewed, Carrier erythrocytes have proven to offer many advantages for delivery of therapeutic agents, especially in the treatment of inherited enzyme deficiency and cancer. Carrier erythrocytes are biodegradable and nonimmunogenic. Encapsulated drugs may be protected from premature degradation, inactivation and excretion. Carrier erythrocytes may be used as a slow-release system. Targeting of encapsulated drugs directly to a site of action is another possibility. Methods for encapsulating drugs into erythrocytes, the fate of carrier erythrocytes in vivo, the strategies of targeting carrier erythrocytes to special organs and in vivo applications of erythrocytes have been discussed. The encapsulation of drugs in erythrocytes has shown attractive possibilites in future use.

• 한국축산식품학회지
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• 제36권1호
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• pp.114-121
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• 2016

This study was performed to improve the techniques used for tenderizing red meat as elderly food. Beef meat was immersed in liposome encapsulated enzyme solution and the effect of protease encapsulation on the beef properties was analyzed. The protease encapsulation properties were analyzed according to the size distribution and enzymatic activity. After enzyme reaction on the beef, the chemical properties of the meat such as pH, water holding capacity, shear rate, lipid oxidation and total volatile basic nitrogen (TVB-N) were analyzed. The pH of the beef increased during the reaction and coating protease (CP) was higher than non-coating protease (NCP). Total color differences were increased remarkably after 36 h and generally, the difference in CP was relatively lower than in NCP. WHC was significantly decreased within 24 h, and no effect from the protease coating was observed. Protease activity was significantly increased within 48 h and no differences in the enzyme coating were observed. The TVB-N value of NCP was increased within 24 h while CP was sustained for up to 36 h. The TVB-N value of protease treated meat increased after 36 h and no effect from the protease coating was detected. Consequently, liposome encapsulated protease was found to have similar properties as non-coated protease. Application of liposome seems to be an interesting option for injecting various functional materials without changing the properties of meat.

• 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.

• Journal of Microbiology and Biotechnology
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• 제28권4호
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• pp.638-644
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• 2018

In this study, the immobilization of xylanase using a protein-inorganic hybrid nanoflower system was assessed to improve the enzyme properties. The synthesis of hybrid xylanase nanoflowers was very effective at $4^{\circ}C$ for 72 h, using 0.25 mg/ml protein, and efficient immobilization of xylanase was observed, with a maximum encapsulation yield and relative activity of 78.5% and 148%, respectively. Immobilized xylanase showed high residual activity at broad pH and temperature ranges. Using birchwood xylan as a substrate, the $V_{max}$ and $K_m$ values of xylanase nanoflowers were 1.60 mg/ml and $455{\mu}mol/min/mg$ protein, compared with 1.42 mg/ml and $300{\mu}mol/min/mg$ protein, respectively, for the free enzyme. After 5 and 10 cycles of reuse, the xylanase nanoflowers retained 87.5% and 75.8% residual activity, respectively. These results demonstrate that xylanase immobilization using a proteininorganic hybrid nanoflower system is an effective approach for its potential biotechnological applications.

• Journal of Microbiology and Biotechnology
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• 제34권6호
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• pp.1189-1196
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• 2024

Bacterial resistance to commonly used antibiotics is one of the major challenges to be solved today. Bacteriophage endolysins (Lysins) have become a hot research topic as a new class of antibacterial agents. They have promising applications in bacterial infection prevention and control in multiple fields, such as livestock and poultry farming, food safety, clinical medicine and pathogen detection. However, many phage endolysins display low bactericidal activities, short half-life and narrow lytic spectrums. Therefore, some methods have been used to improve the enzyme properties (bactericidal activity, lysis spectrum, stability and targeting the substrate, etc) of bacteriophage endolysins, including deletion or addition of domains, DNA mutagenesis, chimerization of domains, fusion to the membrane-penetrating peptides, fusion with domains targeting outer membrane transport systems, encapsulation, the usage of outer membrane permeabilizers. In this review, research progress on the strategies for improving their enzyme properties are systematically presented, with a view to provide references for the development of lysins with excellent performances.

• KSBB Journal
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• 제22권1호
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• pp.7-15
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• 2007

진균류 추출물로부터 신규 멜라닌 분해효소의 분리 및 분해능 test는 멜라닌 분해효소의 균사체 배양 상등액으로 분비 생산됨을 분해능 테스트를 통하여 확인하였고, 이 분해 효소에 의한 멜라닌 분해반응은 pH 7에서 가장 높고, 30$^{\circ}C$에서 가장 안정함을 확인하였다. 멜라닌 분해 효소의 characterization은 2D-gel을 이용하여 멜라닌 분해효소 중 한 가지 효소의 pI값이 약 6.5이고 Molecular weight는 약 54-57 kDa임을 알 수 있었고, 정제된 멜라닌 분해 효소의 전체적인 단백질 및 유전자 서열을 분석하여 degenerate primer를 합성하였으며, RT-PCR 법을 이용하여 유전자를 확보하였다. 멜라닌 분해효소 생산을 위한 진균류의 배양방법 확립은 멜라닌 분해효소가 최대 활성을 갖는 배지 조건은 ammonium tartrate 0.4% : glucose 2% 배지에 yeast extract를 0.1%를 첨가한 배지임을 확인하였고, 진군류의 최적 배양온도는 24-26$^{\circ}C$였으며, 이 때 건조 균체 중량으로 약 6 g/L의 균체를 얻을 수 있었다. 또한 진균류 성장의 최적 pH는 약 5.5로서 이 경우 건조균체중량이 약 6.6 g/L였다. 정제공정은 최적화를 통하여 멜라닌 분해효소의 정제 순도 90% 이상의 정제공정을 확립하였다. Scale-up은 5 L fermenter를 이용한 기초 배양공정을 확립하여 500 L fermenter로의 경제성 있는 scale up에 성공하였고, 이 때 건조균체중량 약 14.5 g/L의 진균류를 얻었으며, 배지 중에 분비 생산된 melanin 분해효소의 양이 300 mg/L에 달하였다. 멜라닌 분해효소의 formulation은 멜라닌 분해효소를 효율적으로 피부로 전달시키기 위하여 50-100 nm 크기로 encapsulation을 실시하여 70 nm, 100 nm size의 nano capsule을 얻었다. 본 연구는 tyrosinase 저해제가 갖는 부작용이 없어 생체 친화적 물질에 의한 부작용 감소 효과가 기대되며, 독자적 기술에 의한 고부가 미백용 화장품 원료 확보로 새로운 기능에 의한 신규시장 창출이 가능하여 미백용 기능성 화장품 원료로서 고부가 화장품에 사용되어 수입대체효과 및 기업의 매출증대 효과가 있을 것으로 기대되어진다.

• 폴리머
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• 제29권6호
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• pp.613-616
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• 2005

본 연구에서는 한 개의 세포와 같은 미세한 생체시료 내부의 분석 대상물질을 감지하는데 사용할 수 있는 광바이오센서를 개발하기 위한 첫 단계로서 효소가 함유된 고분자 수화젤 구형입자를 나노크기로 중합하는 방법을 확립하고 센서로서의 사용 가능성을 확인하였다. 현탁 광중합을 통하여 305 nm의 평균크기를 가지는 horseradish peroxidase(HRP)가 함유된poly(ethylene glycol)(PEG) 수화젤 구형입자를 합성하였으며, 중합반응 이후 입자내부의 효소의 존재 및 활성유지를 HRP와$\H_{2}O_{2}$의 효소반응에 의한 Amplex Red의 형광산화물 생성을 통하여 확인하였다. 합성된 HRP가 함유된 PEG 수화젤 입자는 Amplex Red의 존재하에 $\H_{2}O_{2}$의 농도가 0에서 11 nM로 미량 변화함에 따라서 형광세기가 약 300$\%$ 증가함을 보여 주었다. 이러한 결과는 효소가 함유된 PEG 수화젤 나노입자를 합성하는 본 기술이 향후 미세한 생체시료 내부의 다양한 분석대상물질을 감지할 수 있는 나노크기의 광바이오센서를 개발하는데 이용 될 수 있는 가능성을 보여준다.