• 전기화학회지
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• 제13권1호
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• pp.70-74
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• 2010

전기화학 반응을 이용한 실리콘 표면상으로의 단백질 고정을 연구하였다. 이를 위해 Nitrobenzendiazonium(NiBD) 양이온을 화학적 환원반응을 통해 수식하고 수식된 실리콘 표면을 전기화학적으로 다시 환원시켜 나이트로 기능기를 일차아민 기능기로 활성화하여 단백질 고정에 이용하였다. 활성화 된 표면에 금 나노입자를 고정하여 일차 아민 생성을 확인하였다. 또한 이 방법을 응용하여 실리콘 나노선 어레이 중 선택된 나노선 만을 활성화하고 단백질을 선택적으로 고정하는 연구를 수행하였다. 이 연구를 통하여 NiBD 양이온의 화학 및 전기화학 반응이 실리콘 나노선 표면으로 단백질의 선택적 고정화에 유용하게 사용될 수 있음을 보였다.

• Journal of Microbiology and Biotechnology
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• 제15권6호
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• pp.1317-1322
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• 2005

This work describes neo-fructooligosaccharides (neo-FOSs) production using the immobilized mycelia of Penicillium citrinum. Some critical factors were evaluated to optimize maximal production of neo-FOS. Optimal alginate and cell concentrations were determined to be $1.96\%$ alginate and $7.17\%$ cell, respectively, by statistical analysis. The optimal concentration of $CaCl_{2}$, which is related to bead stability, was determined to be 2 M. It was possible to increase the neo-FOS production by adding 15 units of glucose oxidase to the batch reaction. By co-immobilizing cells and glucose oxidase, neoFOS productivity increased $123\%$ compared with the whole-cell immobilization process. Based on the results above, a co-immobilization technique was developed and it can be utilized for large-scale production.

• Journal of Microbiology and Biotechnology
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• 제24권5호
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• pp.639-647
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• 2014

Laccases have a broad range of industrial applications. In this study, we immobilized laccase on $SiO_2$ nanoparticles to overcome problems associated with stability and reusability of the free enzyme. Among different reagents used to functionally activate the nanoparticles, glutaraldehyde was found to be the most effective for immobilization. Optimization of the immobilization pH, temperature, enzyme loading, and incubation period led to a maximum immobilization yield of 75.8% and an immobilization efficiency of 92.9%. The optimum pH and temperature for immobilized laccase were 3.5 and $45^{\circ}C$, respectively, which differed from the values of pH 3.0 and $40^{\circ}C$ obtained for the free enzyme. Immobilized laccase retained high residual activities over a broad range of pH and temperature. The kinetic parameter $V_{max}$ was slightly reduced from 1,890 to 1,630 ${\mu}mol/min/mg$ protein, and $K_m$ was increased from 29.3 to 45.6. The thermal stability of immobilized laccase was significantly higher than that of the free enzyme, with a half-life 11- and 18-fold higher at temperatures of $50^{\circ}C$ and $60^{\circ}C$, respectively. In addition, residual activity was 82.6% after 10 cycles of use. Thus, laccase immobilized on $SiO_2$ nanoparticles functionally activated with glutaraldehyde has broad pH and temperature ranges, thermostability, and high reusability compared with the free enzyme. It constitutes a notably efficient system for biotechnological applications.

• KSBB Journal
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• 제19권5호
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• pp.399-405
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• 2004

A reticulated PU-g-PAAc foam was modified through the surface treatment of PU foam by one atmospheric pressure plasma. The synthesized PU-g-PAAc foam was prepared for the purpose of immobilizing microbial organisms. We also attempted different plasma treatment methods including simple plasma treatment, plasma induced grafting and plasma induced grafting followed by plasma re-treatment. The effect of grafting on equilibrium water content (EWC) of PU forms was examined by swelling measurements. Adhesion test was performed to investigate the effect of different plasma treatment methods on the improvement of microbial immobilization. Two foams modified by plasma induced grafting and plasma re-treatment after grafting showed 2.7 and 3.0 fold higher microbial immobilization than unmodified one, respectively. Meanwhile, simple plasma treatment showed a little enhancement. FT-IR analysis of each sample verified the contribution of surface functional groups on the enhancement of microbial immobilization. SEM observation confirmed microbial adherence.

• Journal of Microbiology
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• 제39권2호
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• pp.83-88
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• 2001

There is considerable interest in how microbiological processes can affect the behaviour of metal contaminants in natural and engineered environments and their potential for bioremediation. The extent to which microorganisms can affect metal contaminants is dependent on the identity and chemical form of the metal and the physical and chemical nature of the contaminated site or substance. In general terms, microbial processes which solubilize metals increase their bioavailability and potential toxicity, whereas those that immobilize them reduce bioavailability. The balance between mobilization and immobilization varies depending on the metal, the organisms, their environment and physico-chemical conditions.

• Journal of Microbiology and Biotechnology
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• 제33권1호
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• pp.127-134
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• 2023

Laccase activity is influenced by copper (Cu) as an inducer. In this study, laccase was immobilized on Cu and Cu-magnetic (Cu/Fe₂O₄) nanoparticles (NPs) to improve enzyme stability and potential applications. The Cu/Fe₂O₄ NPs functionally activated by 3-aminopropyltriethoxysilane and glutaraldehyde exhibited an immobilization yield and relative activity (RA) of 93.1 and 140%, respectively. Under optimized conditions, Cu/Fe₂O₄ NPs showed high loading of laccase up to 285 mg/g of support and maximum RA of 140% at a pH 5.0 after 24 h of incubation (4℃). Immobilized laccase, as Cu/Fe₂O₄-laccase, had a higher optimum pH (4.0) and temperature (45℃) than those of a free enzyme. The pH and temperature profiles were significantly improved through immobilization. Cu/Fe₂O₄-laccase exhibited 25-fold higher thermal stability at 65℃ and retained residual activity of 91.8% after 10 cycles of reuse. The degradation of bisphenols was 3.9-fold higher with Cu/Fe₂O₄-laccase than that with the free enzyme. To the best of our knowledge, Rhus vernicifera laccase immobilization on Cu or Cu/Fe₂O₄ NPs has not yet been reported. This investigation revealed that laccase immobilization on Cu/Fe₂O₄ NPs is desirable for efficient enzyme loading and high relative activity, with remarkable bisphenol A degradation potential.

• Journal of Microbiology and Biotechnology
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• 제14권5호
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• pp.1043-1046
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• 2004

The stability and electrochemical properties of a self-assembled layer of spinach ferredoxin on a quartz substrate and on a highly oriented pyrolytic graphite electrode were investigated. To fabricate the ferredoxin self-assembly layer, dimyristoylphosphatidylcholine was first deposited onto a substrate for ferredoxin immobilization. Surface analysis of the ferredoxin layer was carried out by atomic force microscopy to verify the ferredoxin immobilization. To verify ferredoxin immobilization on the lipid layer and to confirm the maintenance of redox activity, absorption spectrum measurement was carried out. Finally, cyclic-voltammetry measurements were performed on the ferredoxin layers and the redox potentials were obtained. The redox potential of immobilized ferredoxin had a formal potential value of -540 mV. It is suggested that the redox-potential measurement of self-assembled ferredoxin molecules could be used to construct a biosensor and biodevice.

• 대한수의학회지
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• 제43권3호
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• pp.501-505
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• 2003

The chemical immobilization in giraffes (Giraffa camelopardalis reticulata) remains a challenge because of their size, behavior, and anatomic and physiologic characteristics that commonly create life threatening problems during immobilization. The drug combination medetomidine (MED) and ketamine (KET) was administered by remote injection. The dosages of MED and KET were correlated to the giraffe's shoulder height (SH), become recumbent with a dosage of $114{\mu}g$ of MED and 2.1 mg of KET, $320{\mu}g$ of atipamezole per cm of SH, respectively. After injection of the drugs, initial signs of sedation including ataxia were noticed at 3 minutes followed by lateral recombency at 12 minutes. The mean heart rate, respiratory rate and rectal temperature recorded during the procedures were 55 beats per minute, 48 breaths per minute and $36.6^{\circ}C$, respectively. Atipamezole was administered, after 33 minutes result in death. Assuming that 24 hours fasting times were short and light esteemed of atipamzole adverse effects like vomiting, passive regurgitation.

• Journal of Microbiology and Biotechnology
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• 제20권7호
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• pp.1086-1091
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• 2010

This study explored the use of gellan gum as an immobilization matrix for the production of cyclosporin A (CyA) by immobilized spores and mycelia of Tolypocladium inflatum MTCC 557. Different carriers, such as gellan gum, sodium alginate, celite beads, and silica, were tested as immobilization carriers, along with the role of the carrier concentration, biomass weight, number of spore-inoculated beads, and repeated utilization of the immobilized fungus. The maximum CyA production was 274 mg/l when using gellan gum [1% (w/v)], and a mycelial weight of 7.5% (w/v) supported the maximum production of CyA. Additionally, the addition of a combination of $_L$-valine (6 g/l) and $_L$-leucine (5 g/l) after 48 h of fermentation produced 1,338 mg/l of CyA when using gellan gum. The immobilized mycelia beads were found to remain stable for four repetitive cycles, indicating their potential for semicontinuous CyA production.

• 유기물자원화
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• 제19권2호
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• pp.16-21
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• 2011

생물흡착제는 그 자체만으로 실제폐수처리에 적용하기에는 충분하지 못한 구조를 가지고 있기 때문에 고정화는 매우 중요하다. 그래서 최근의 연구는 생물흡착제를 효과적으로 고정화시키는 방법에 초점이 맞추어져 있다. 미생물이나 다당류와 같은 생물흡착제의 기계적 강도를 향상시키기 위하여 지금까지 많은 고정화 방법이 제안되어 왔다. 본 연구에서는 다양한 고정화 방법들(adsorption, covalent binding, entrapment, encapsulation, and crosslinking)을 소개하고자 한다.