• Title/Summary/Keyword: deactivation kinetics

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Prediction of Continuous Reactors Performance Based on Batch Reactor Deactivation Kinetics Data of Immobilized Lipase

  • Murty, V.Ramachandra;Bhat, Jayadev;Muniswaran, P.K.A.
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.7 no.4
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    • pp.225-230
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    • 2002
  • Experiments on deactivation kinetics of immobilized lipase enzyme from Candida cyl-indracea were performed in stirred bath reactor using rice bran oil as the substrate and temperature as the deactivation parameter. The data were fitted In first order deactivation model. The effect of temperature on deactivation rate was represented by Arrhenius equation. Theoretical equations were developed based on pseudo-steady state approximation and Michaelis -Menten rate expression to predict the time course of conversion due to enzyme deactivation and apparent half-life of the immobilized enzyme activity in PFR and CSTH under constant feed rate polity for no diffusion limitation and diffusion limitation of first order. Stability of enzyme in these continuous reactors was predicted and factors affecting the stability were analyzed.

Deactivation Kinetics in Heavily Boron Doped Silicon Using Ultra Low Energy Ion Implantation (초 저 에너지 이온주입으로 고 조사량 B 이온 주입된 실리콘의 Deactivation 현상)

  • Yoo, Seung-Han;Ro, Jae-Sang
    • Korean Journal of Materials Research
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    • v.13 no.6
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    • pp.398-403
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    • 2003
  • Shallow $p^{+}$ n junction was formed using a ULE(ultra low energy) implanter. Deactivation phenomena were investigated for the shallow source/drain junction based on measurements of post-annealing time and temperature following the rapid thermal annealing(RTA) treatments. We found that deactivation kinetics has two regimes such that the amount of deactivation increases exponentially with annealing temperature up to $850^{\circ}C$ and that it decreases linearly with the annealing temperature beyond that temperature. We believe that the first regime is kinetically limited while the second one is thermodynamically limited. We also observed "transient enhanced deactivation", an anomalous increase in sheet resistance during the early stage of annealing at temperatures higher than X$/^{\circ}C$. Activation energy for transient enhanced deactivation was measured to be 1.75-1.87 eV range, while that for normal deactivation was found to be between 3.49-3.69 eV.

Hydrolysis of Oils by Using Immobilized Lipase Enzyme : A Review

  • Murty, V.Ramachanda;Bhat, Jayadev;Muniswaran, P.K.A.
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.7 no.2
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    • pp.57-66
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    • 2002
  • This review focuses on the use of immobilized lipase technology for the hydrolysis of oils. The importance of lipase catalyzed fat splitting process, the various immobilization procedures, kinetics, deactivation kinetics, New immobilized lipases for chiral resolution, reactor configurations, and process considerations are all reviewed and discussed.

Deactivation kinetics of C. rugosa lipase

  • 손현수;이준식
    • Proceedings of the Korean Society for Applied Microbiology Conference
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    • 1986.12a
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    • pp.523.1-523
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    • 1986
  • To extend the spectrum of enzyme utilization in the organic solvent system, C. rugosal lipase was selected as a model enzyme because its substrate is soluble to organic solvent. One of the serious disadvantages in this system was the deactivation of the lipase. The pattern of lipase deactivation was the biphasic model. The activation energies for the deactivation were 14.05${\times}$10$^4$ KJ/Kg mole in the first phase and 3.59 ${\times}$ 10$^4$ KJ/mole in the second phase. The several factors were studied for their influences on the pattern of deactivation. Iso-octane as organic solvent influenced more on the first phase than the second phase. Urea as the reagent affecting boty hydrophobic interaction and hydrogen bond of enzyme also influencea more on the first phase. And the optimum pH for the activity was not correlated to that of the stability.

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Deactivation of Porous Photocatalytic Particles During a Wastewater Treatment Process

  • Cho, Young-Sang;Nam, Soyoung
    • Korean Chemical Engineering Research
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    • v.57 no.2
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    • pp.185-197
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    • 2019
  • Deactivation of porous photocatalytic materials was studied using three types of microstructured particles: macroporous titania particles, titania microspheres, and porous silica microspheres containing CNTs and $TiO_2$ nanoparticles. All particles were synthesized by emulsion-assisted self-assembly using micron-sized droplets as micro-reactors. During repeated cycles of the photocatalytic decomposition reaction, the non-dimensionalized initial rate constants (a) were estimated as a function of UV irradiation time (t) from experimental kinetics data, and the results were plotted for a regression according to the exponentially decaying equation, $a=a_0\;{\exp}(-k_dt)$. The retardation constant ($k_d$) was then compared for macroporous titania microparticles with different pore diameters to examine the effect of pore size on photocatalytic deactivation. Nonporous or larger macropores resulted in smaller values of the deactivation constant, indicating that the adsorption of organic materials during the photocatalytic decomposition reaction hinders the generation of active radicals from the titania surface. A similar approach was adopted to evaluate the activation constant of porous silica particles containing CNT and $TiO_2$ nanoparticles to compare the deactivation during recycling of the photocatalyst. As the amount of CNTs increased, the deactivation constant decreased, indicating that the conductive CNTs enhanced the generation of active radicals in the aqueous medium during photocatalytic oxidation.

Adsorption Analysis of Benzene Vapor in a Fixed-Bed of Granular Activated Carbon (활성탄 충전층에서 벤젠 증기의 흡착특성)

  • Kim, Seong-Soo;Kim, Jong-Hyun;Park, Sang-Wook
    • Korean Chemical Engineering Research
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    • v.47 no.4
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    • pp.495-500
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    • 2009
  • Activated carbon was used as an adsorbent to capture benzene vapor from gaseous stream of nitrogen in a fixed-bed to obtain the breakthrough data. The deactivation model is used to analyze the adsorption kinetics of benzene vapor using the experimental breakthrough data. The experimental breakthrough data are fitted very well to the deactivation model than the adsorption isotherm models in the literature.

Sorption Analysis of Carbon Dioxide onto Cesium Carbonate (세슘카보네이트에서 이산화탄소의 수착반응)

  • Son, Young-Sik;Kim, Seong-Soo;park, Sang-Wook
    • Korean Chemical Engineering Research
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    • v.47 no.3
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    • pp.373-379
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    • 2009
  • Cesium carbonate was used as an adsorbent to capture carbon dioxide from gaseous stream of carbon dioxide, nitrogen, and moisture in a fixed-bed to obtain the breakthrough data of $CO_2$. The deactivation model in the non-catalytic heterogeneous reaction systems is used to analyze the sorption kinetics among carbon dioxide, carbonate, and moisture using the experimental breakthrough data. The experimental breakthrough data are fitted very well to the deactivation model than the adsorption isotherm models in the literature.

Extraction Process and Stability Characteristics of Soybean Peroxidase (Soybean peroxidase의 추출공정 및 안정성 특성)

  • 서경림;이은규
    • KSBB Journal
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    • v.13 no.5
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    • pp.599-605
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    • 1998
  • Soybean peroxidase was extracted from soybean hulls and purified by ammonium sulfate precipitations (25% and 75% saturation), pl fractionation, and anionic exchange and gel filtration chromatographies (DEAE-Sephadex A-50 and Superose 12). Modlecular weight and pl value were estimated to be ca. 45 kD and 4.2, respectively. Purified soybean peroxidase had an RZ value of 0.43. Compared with horseradish peroxidase, it showed superior thermal and pH stability. Assuming the first-order kinetics, the thermal deactivation rate constant of soybean peroxidase at 80$^{\circ}C$ was about 8 times lower than that of horseradish peroxidase. Deactivation energy was calculated to be 69.3 kcal/mol. Soybean peroxidase showed about 10% higher H2O2 degradation capacity than horseradish peroxidase. Exploiting these advantages, the soybean peroxidase purified from the domestic soybean hull is expected to replace horseradish peroxidase in various applications.

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Decursin from Angelica gigas Nakai Blocks hKv1.5 Channel

  • Kwak, Yong-Geun;Choi, Bok-Hee;Kim, Dae-Keun;Eun, Jae-Soon
    • Biomolecules & Therapeutics
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    • v.19 no.1
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    • pp.33-37
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    • 2011
  • Decursin was purified from Angelica gigas Nakai, and its effects on the human Kv1.5 (hKv1.5) currents were recorded in mouse fibroblasts ($Ltk^-$ cells) by whole-cell patch-clamp technique. Decursin inhibited hKv1.5 current in a concentration-dependent manner, with an $IC_{50}$ value of $2.7\;{\mu}M$ at +60 mV. Decursin accelerated the inactivation kinetics of the hKv1.5 channel, and slowed the deactivation kinetics of the hKv1.5 current, resulting in a tail crossover phenomenon. Also, decursin inhibited the hKv1.5 current in a use-dependent manner. These results strongly suggest that decursin is a kind of open-channel blocker of the hKv1.5 channel.

Immobilization of Diatom Phaeodactylum tricornutum with Filamentous Fungi and Its Kinetics

  • Tyler J. Barzee;Hamed M. El-Mashad;Andrew R. Burch;Annaliese K. Franz;Ruihong Zhang
    • Journal of Microbiology and Biotechnology
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    • v.33 no.2
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    • pp.251-259
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    • 2023
  • Immobilizing microalgae cells in a hyphal matrix can simplify harvest while producing novel mycoalgae products with potential food, feed, biomaterial, and renewable energy applications; however, limited quantitative information to describe the process and its applicability under various conditions leads to difficulties in comparing across studies and scaling-up. Here, we demonstrate the immobilization of both active and heat-deactivated marine diatom Phaeodactylum tricornutum (UTEX 466) using different loadings of fungal pellets (Aspergillus sp.) and model the process through kinetics and equilibrium models. Active P. tricornutum cells were not required for the fungal-assisted immobilization process and the fungal isolate was able to immobilize more than its original mass of microalgae. The Freundlich isotherm model adequately described the equilibrium immobilization characteristics and indicated increased normalized algae immobilization (g algae removed/g fungi loaded) under low fungal pellet loadings. The kinetics of algae immobilization by the fungal pellets were found to be adequately modeled using both a pseudo-second order model and a model previously developed for fungal-assisted algae immobilization. These results provide new insights into the behavior and potential applications of fungal-assisted algae immobilization.