Wyniki wyszukiwania - Biblioteka Nauki

1

Chitosan immobilization to the polypropylene nonwoven after activation in atmospheric – pressure nitrogen plasma

100%

Černáková Ľ. , Černák M. , Tóth A. , Mikulášová M. , Tomašková M. , Kováčik D.

Open Chemistry

|

2015

|

tom 13

|

nr 1

EN

Atmospheric-pressure air and nitrogen plasmas generated by surface dielectric barrier discharges have been used to incorporate new functionalities at the surface of polypropylene nonwoven fabric. The main goals were to activate the polymer surfaces for subsequent immobilization of chitosan from water solution without using any crosslinking and wetting agents. The samples were analyzed by diffuse reflectance infrared Fourier transform spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. The nitrogen plasma treatment resulted in relatively high oxygen incorporation, about 9 atomic % mainly in aliphatic C=O type bonds and about 4 at.% of nitrogen incorporation in amine and other nitrogen functionalities. Chitosan was immobilized on the fabric fibers surfaces very homogeneously in amount of 2 - 5 g m-2. The chitosan coated samples exhibited a good laundering durability and strong antimicrobial activity against Bacillus subtilis and Escherichia coli.

2

Screening of lipase carriers for reactions in water, biphasic and pure organic solvent systems

100%

Hrydziuszko Z. , Dmytryk A. , Majewska P. , Szymańska K. , Liesiene J. , Jarzębski A. , Bryjak J.

Acta Biochimica Polonica

|

2014

|

tom 61

|

nr 1

1-6

EN

In bioprocesses lipases are typically used in immobilized form, irrespective of type of reaction systems, to ensure an even distribution of catalysts in water restricted media and/or to facilitate separation and reuse. In these studies we report on the selection of appropriate enzyme-carrier preparation for hydrolysis reaction in aqueous and biphasic systems and transesterification in organic solvent. For this Candida rugosa lipase was bound by adsorption or covalent attachment onto various carriers to give 24 preparations. Selection of proper preparation was based on reactivity, thermal stability (4 h at 60°C), possibility of drying and operational stability in 17-23 successive batch processes of 4-nitrophenyl palmitate hydrolysis in water. Activity of preparations varied from 20 to 5100 U∙mL-1 but the most stable preparations were those of moderate activity: bound by adsorption or covalent attachment to NH2-Kieselgel or acrylic carrier (retained activity over 90%). Selected preparations were used for hydrolysis of ethyl (1-butyryloxyethyl)-phenylphosphinate in biphasic system, and, after drying, in ethyl (1-hydroxyethyl)-phenyl-phosphinate transesterification. In this study operational stability was the principal criterion of selection. In water system, lipase covalently bound to NH2-Kieselgel was the best - preserved 50% of initial activity in consecutive batch processes. In biphasic system and lipase covalently bound to acrylic and NH2-Kieselgel the values were 90 or 77%, respectively, whereas in organic solvent, when lipase was immobilized on NH2-Kieselgel by adsorption, it was 50%. Thus, NH2-Kieselgel appears to be an universal matrix for investigated lipase immobilization and can be used in all reaction systems.

3

Studies on the treatment of waste slurries containing heavy metal

100%

Paszek A.

Polish Journal of Chemical Technology

|

2007

|

tom 9

|

nr 2

81-82

EN

Immobilization of heavy metals in the waste with the use of cement matrix has been investigated. The quality of the obtained granulated products has been assessed and the possible areas of application have been indicated.

4

Immobilization of Catalase via Adsorption onto Natural and Modified Montmorillanit Analsim-Clay

100%

Alkan S. , Gür T. , Gür A. , Uruc H. , Demir H.

|

2009

|

tom Vol. 83, nr 12

2089-2095

EN

Immobilization of the enzyme catalase on natural and modified montmorillanit analsimclays was investigated using a batch system. Such an immobilization does not result in enzyme in activation and constitutes a valuable method for immobilizing catalase at high ionic strength. In the immobilization process, the effect of pH, ionic strength and reaction temperature were chosen as parameters. Further more the optimization of immobilization conditions were studied using data obtained from experimental results. For the free catalase and three different immobilized catalase enzymes, the optimum pH values 8, 7, 7 and 8; reaction temperature 30°C; ionic strength 0.25 M were found. It was determined that enzyme activity for enzyme supported by natural clay was 73.3 percent, when it was retained during the storage at 4°C for a period of 60 days. It was observed that storage and operational stabilities of the enzyme in creased with immobilization. The results obtained show that montmorillanit analsim-clay is valuable and favour able support the simple adsorption of enzymes.

5

β-Galactosidase from Penicillium canescens. Properties and immobilization

100%

Budriene S. , Gorochovceva N. , Romaskevic T. , Yugova L. , Miezeliene A. , Dienys G. , Zubriene A.

Open Chemistry

|

2005

|

tom 3

|

nr 1

95-105

EN

β-galactosidase from Penicillium canescens was immobilized on chitosan, sepharose-4B, foamable polyurethane and some other carriers. The highest yield of immobilization (up to 98%) was obtained by using chitosan as a carrier. The optimum pH and temperature were not significantly altered by immobilization. High stability of immobilized β-galactosidase during storage was demonstrated. Efficient lactose saccharification (over 90%) in whey was achieved by using immobilized β-galactosidase.

6

Cross-linked enzyme aggregates (CLEA) in enzyme improvement – a review

100%

Velasco-Lozano S. , López-Gallego F. , Mateos-Díaz J. C. , Favela-Torres E.

Biocatalysis

|

2014

|

tom 1

|

nr 1

EN

Structural and functional catalytic characteristics of cross-linked enzyme aggregates (CLEA) are reviewed. Firstly, advantages of enzyme immobilization and existing types of immobilization are described. Then, a wide description of the factors that modify CLEA activity, selectivity and stability is presented. Nowadays CLEA offers an economic, simple and easy tool to reuse biocatalysts, improving their catalytic properties and stability. This immobilization methodology has been widely and satisfactorily tested with a great variety of enzymes and has demonstrated its potential as a future tool to optimize biocatalytic processes.

7

THE PREVENTIVE EFFECTS OF RUTIN ON IMMOBILIZATION STRESS-INDUCED CARDIAC DAMAGE IN RATS

100%

Coskun R. , Inan A. , Suleyman Z. , Cimen F. K. , Cankaya M.

Acta Poloniae Pharmaceutica - Drug Research

|

2019

|

tom 76

|

nr 6

1079-1087

EN

Background: The previous studies formed the role of oxidants and proinflammatory cytokines in the pathogenesis of acute psychological stress-related cardiac damage leading to mortality and other complications. The aim of the study is to examine the protective effect of rutin against stress-induced cardiac damage. In the literature, no studies have been found analyzing the effects of rutin in acute stress related oxidative damage induced by immobilization method in rats.Material and Methods: Rutin was administered orally to rutin + stress applied (RSG) group albino rats at a dose of 50 mg/kg. For healthy control (HG) and stress applied to control (SAG) groups, distilled water as a solvent was orally administered at the same volume (0.5 ml). One hour after rutin and distilled water applications, all animals except for HG brought into supine position and their legs and arms were ligated and kept in the same position for 24 hours.Results: Oxidant, cytokine and cardiac biomarker levels in blood serum and heart tissues of SAG animals were found to be significantly higher and total glutathione was lower than RSG and HG groups. Histopathologically dilated conjugated blood vessels and myocardial destruction, hemorrhage, edema, and polymorphonuclear leucocyte infiltration were observed in the SAG heart tissues. On the other hand, the histological heart tissue results of the RSG group was found to be similar compare to healthy tissue except for the slightly dilated conjugated blood vessel. Conclusion: These results indicate that the rutin may be useful in the treatment of stress-related oxidative cardiac damage

8

Determination of biodegradation rate of carrier for microorganism immobilization fabricated based on starch

88%

Tomaszewska-Ciosk E. , Golachowski A. , Zdybel E.

Polish Journal of Chemical Technology

|

2013

|

tom 15

|

nr 3

110-114

EN

The study was aimed on the determination of biodegradation rate of extruded starch carriers, with or without immobilized microorganisms in diversified storage conditions. The research was conducted on potato starch, in which Saccharomyces cerevisiae yeast cells were immobilized. Preparations with and without yeasts were than placed for 84 days in the environments of: light soil, heavy soil, compost, water and activated sludge. After 0, 7, 14, 21, 49 and 84 days of storage the preparations were perfused with water and analyzed. In the recovered samples the following tests were carried out: the force causing fracture, the elongation caused by the mentioned force, the mass and the diameter of the carrier. Due to the degradation the size and the mechanical properties of the samples were decreased. The rate of the degradation was strongly dependent on the environment of the storage. The fastest degradation of the carriers were observed for compost and heavy soil, while the slowest biodegradation was observed for the samples placed in the water environment. The rate of biodegradation was also influenced by the Saccharomyces cerevisiae yeasts. The rate of biodegradation was faster in the samples containing yeast cells, than in the extrudates without the microorganisms.

9

Monitoring and evaluation of muscle atrophy: a much needed step in critically ill COVID-19 patients

88%

Kumar A. , Kumar A. , Kumar N. , Kumar A. , Sinha C. , Kumari P. , Singh V.

Critical Care Innovations

|

2021

|

tom 4

|

nr 1

30-43

XX

INTRODUCTION: Elderly COVID-19 patients admitted to the intensive care unit (ICU) are at high risk of an inflammatory syndrome, hypercatabolic reaction, malnutrition, and physical immobilization. This may result in loss of muscle mass and pulmonary infection leading to prolonged ventilatory support. Factors responsible for muscle mass loss in ICU are (1) microcirculatory disturbances, (2) presence of systemic inflammatory response syndrome (SIRS), (3) sepsis (4) drugs (corticoids, neuromuscular blockers) having inhibitory activity on the nervous system, neuromuscular junction and muscle itself. Mechanism of muscle atrophy in critically ill elderly patients include an imbalance between protein synthesis and degradation. Interventions to manage muscle atrophy for the patients admitted to ICU is also extrapolated to mechanically ventilated COVID-ARDS patients. PURPOSE: Early recognition of factors contributing to intensive care unit acquired weakness (ICUAW) in COVID-19 patients, inflammation, high catabolic phase, steroid use, and paralysis. The potential interventions to target these specific mechanisms and ameliorate muscle dysfunction in COVID-19 patients. CONCLUSIONS:Intensive care unit acquired weakness (ICUAW) in critically ill COVID-19 patients is due to severity of illness, co-morbidities, muscle unloading, or ICU treatments, a systemic reaction circulating within the body, or combinations therein. Furthermore, the availability of a culture model of ICUAW could facilitate in expediting the diagnosis of ICUAW and fast track the discovery of putative treatments. We recommend NIV or HFNC ventilation or early weaning from invasive mechanical ventilation in critically ill COVID-19 elderly patients.

10

Optical properties of silver nanocube surfaces obtained by silane immobilization

88%

Merk V. , Nerz A. , Fredrich S. , Gernert U. , Selve S. , Kneipp J.

Nanospectroscopy

|

2014

|

tom 1

|

nr 1

EN

Silver nanocubes were synthesized by the polyol method and immobilized on a surface in a simple approach using an aminopropyltriethoxysilane (APTES). The optical and structural properties of the polyvinylpyrrolidone (PVP) stabilized nanocubes were investigated in solution and on glass surfaces. The SERS enhancement factors at two excitation wavelengths for crystal violet were compared with electric fields arising in different nano¬particle configurations using finite-difference time-domain simulations. They are in agreement with the preferred face-to-face orientation in the nanoaggregates on the surfaces. The facile immobilization enables on-demand preparation and use of the nanocubes in real analytical applications.

11

Biosynthesis of ethyl butyrate with immobilized Candida rugosa lipase onto modified Eupergit®C

88%

Spinelli D. , Coppi S. , Basosi R. , Pogni R.

Biocatalysis

|

2014

|

tom 1

|

nr 1

EN

Lipase from Candida rugosa was immobilized onto the modified Eupergit®C. The support was treated with ethylenediamine and subsequently activated with glutaraldehyde. Enzyme immobilization efficiency was 85%. The optimum pH was close to 6.5 for both the free and immobilized lipase. Immobilized lipase retained its maximum activity in a temperature range of 55 – 60°C. Subsequently, ethyl butyrate synthesis was investigated using immobilized enzyme by esterification of butyric acid with ethanol in solvent-free conditions (23% product yield) and using hexane as a solvent (65% product yield). The acid-alcohol molar ratio and different enzyme amounts were tested as efficient reaction parameters. The biocatalyst maintained 60% of its activity when reused in 8 successive batch reactions in organic solvent. Therefore, the immobilized lipase has demonstrated its potential in practical applications such as short-chain ester synthesis for the food industry.

12

CYCLICAL METAL ADSORPTION AND DESORPTION THROUGH SLUDGE IMMOBILIZED IN CHITOSAN MEDIA

88%

Kuczajowska-Zadrożna M. , Filipkowska U. , Jóźwiak T. , Szymczyk P.

Progress on Chemistry and Application of Chitin and its Derivatives

|

2016

|

tom 21

135-146

EN

In this research, a cyclical adsorption/desorption of cadmium and zinc from solutions containing a single metal or its mixture in ratio of 1:1 and 1:2 using immobilized activated sludge in the chitosan (ASC) was examined. In the adsorption studies, the optimal dose of ASC was 4 g/L. The highest desorption efficiency was achieved for 1M HNO3. Both adsorption and desorption occurred in accordance with a pseudo-second order reactions which is confirmed by R2 values. Mass of zinc adsorbed and desorbed in one cycle from a solution containing a single metal was 0.78 and 0.40 mmol/g d.w. when cadmium was lower (respectively 0.41 and 0.21 mmol/g d.w.). In subsequent cycles, both metals were adsorbed and desorbed at a lower efficiency. The highest efficiency of desorption was observed for a mixture of Cd:Zn in the ratio of 1:1 and 1:2, respectively 86% and 89% of cycle1, whereas for the zinc it was 70% and 53%. Desorption efficiency of both metals and its mixtures, in subsequent cycles gradually decreased.

13

Enzymatic microreactors in biocatalysis: history, features, and future perspectives

88%

Laurenti E. , dos Santos Vianna Jr. A.

Biocatalysis

|

2014

|

tom 1

|

nr 1

EN

Microfluidic reaction devices are a very promising technology for chemical and biochemical processes. In microreactors, the micro dimensions, coupled with a high surface area/volume ratio, permit rapid heat exchange and mass transfer, resulting in higher reaction yields and reaction rates than in conventional reactors. Moreover, the lower energy consumption and easier separation of products permit these systems to have a lower environmental impact compared to macroscale, conventional reactors. Due to these benefits, the use of microreactors is increasing in the biocatalysis field, both by using enzymes in solution and their immobilized counterparts. Following an introduction to the most common applications of microreactors in chemical processes, a broad overview will be given of the latest applications in biocatalytic processes performed in microreactors with free or immobilized enzymes. In particular, attention is given to the nature of the materials used as a support for the enzymes and the strategies employed for their immobilization. Mathematical and engineering aspects concerning fluid dynamics in microreactors were also taken into account as fundamental factors for the optimization of these systems.

14

Biosorption of Uranium on Immobilized Microalgae

88%

Tobilko V. , Lypskyi V. , Kovalchuk I. , Spasonova I. , Kornilovich B.

|

2008

|

tom Vol. 82, nr 1-2

249-254

EN

The biological method of purification of water from uranium(VI) has been studied. The sorption capacity of the immobilized microalgae on the clay minerals as concerns uranium was established. Algal biomass of Scenedesmus acutus, Chlorella vulgaris and Microcoleus vaginatus and algae Neocystis broadiensis demonstrated high effectiveness in uranium sorption, and proved to be an excellent representative to remove uranium from contaminated water.

15

An organic solvent and surfactant stable α-amylase from soybean seeds

75%

Jaiswal N. , Prakash O.

Acta Biochimica Polonica

|

2013

|

tom 60

|

nr 3

387-393

EN

An organic solvent and surfactant stable α-amylase was obtained from soybean seeds. The direct and indirect effect of various organic solvents (non-polar, polar protic, and polar aprotic) and surfactants on the activity and stability of free enzyme was determined. The enzyme showed a very high catalytic efficiency and stabilization against most of the organic solvents and surfactants tested, except for few. Those organic solvents and surfactants (like chloroform, dimethyl formamide, n-butanol, and Tween 20), which caused an inhibition in enzyme activity, were used to study their effects on immobilized enzyme. The inhibitory effect was found to be decreased in immobilized enzyme as compared to free enzyme indicating that immobilization imparted stability to the enzyme. Moreover, the possibility of reuse of the enzyme in the presence of the organic solvents and surfactants was increased upon immobilization. The stability of soybean α-amylase towards organic solvents and surfactants shows that it is a potential candidate for use in organic-solvent biocatalysis as well as in detergent industries.

16

Immobilization of selected heavy metals from fly ash from thermal treatment of municipal sewage sludge in hardening slurries

75%

Szarek Ł. , Falaciński P. , Wojtkowska M. , Szarek Ł. , Falaciński P. , Wojtkowska M.

|

17

Badania nad utylizacją szlamu zawierającego metale ciężkie

75%

Paszek A.

|

2007

|

tom Vol. 60, nr 10

488-490

PL

Wykonano badania immobilizacji metali ciężkich w odpadzie z zastosowaniem matrycy cementowej. Sprawdzono jakość uzyskanych granulatów i określono kierunki ich wykorzystania.

EN

Immobilization of heavy metals in waste with the use of cement matrix has been investigated. The quality of granulated products obtained has been assessed and possible areas of application have been indicated.

18

Enzymatyczna deacetylacja chitozanu

63%

Jaworska M. M.

|

2011

|

tom Vol. 35, z. 3

3-119

PL

Enzymatyczna deacetylacja chitozanu jest procesem, który może w najbliższej przyszłości stać się interesującą alternatywą dla chemicznej modyfikacji tego polimeru. Proces enzymatyczny, podobnie jak chemiczny, prowadzi do przekształcenia merów N-acetyloglukozoaminy w mery glukozoaminy, lecz prowadzony jest w warunkach znacznie łagodniejszych i nie jest związany z jednoczesną hydrolizą łańcucha polimeru. Modyfikacja enzymatyczna pozwala także na prowadzenie procesu w warunkach kontrolowanych, co umożliwiłoby produkowanie chitozanu o z góry określonym stopniu acetylacji. W badaniach stosowano deacetylazę chitynową wydzieloną z biomasy grzybów strzępkowych Absidia orchidis vel coerulea NCAIM F 00642. W pracy scharakteryzowano enzym wykazując, że ma on maksymalną aktywność przy pH wynoszącym 4.0, (pH-stabilność w zakresie od 1.0 do 9.0) oraz w temperaturze 55°C. Zaproponowano także model opisujący termostabilność deacetylazy chitynowej w temperaturze pracy (50°C). Badania kinetyczne wykazały, że enzymatyczna deacetylacja chitozanu może być opisana za pomocą modelu zaproponowanego przez Michaelisa-Menten, z tym, że enzym podlega jednocześnie inhibicji współzawodniczącej wywołanej przez uwalniany kwas octowy. Równanie kinetyczne skorelowano z aktywnością preparatu enzymatycznego, co dawało lepszą zgodność z danymi doświadczalnymi niż oryginalna zależność oparta na stężeniu enzymu. Przeprowadzono badania mające na celu dobór właściwego nośnika do immobilizacji deacetylazy chitynowej oraz określenie kinetyki deacetylacji chitozanu przez enzym immobilizowany. Stwierdzono, że najlepsze efekty daje immobilizacja na nośniku DEAE-Granocel aktywowanym diwinylosulfonem w środowisku alkalicznym (pH 8.0). Warunki, przy których preparat wykazywałmaksymalną aktywność, były zbliżone do tych dla enzymu natywnego : pH = 4.0 i temperatura 45°C. Stwierdzono także, że enzymatyczna deacetylacja chitozanu z wykorzystaniem enzymu immobilizowanego może być również opisana za pomocą zależności zaproponowanej przez Michaelisa-Menten. Wykazano jednak, że otrzymany preparat stracił aktywność po trzykrotnym zastosowaniu w reaktorze okresowym, przy prowadzeniu doświadczeń w odstępach dwudziestoczterogodzinnych. Na końcowym etapie prac zbadano możliwość zastosowania reaktora membranowego do enzymatycznej deacetylacji chitozanu. Określono parametry w istotny sposób wpływające na badany proces. Analiza uzyskanych danych wykazała, że w obszarze przepływów laminarnych cieczy (Recm do 1700) oraz w obszarze mieszania w reaktorze zbiornikowym z mieszadłem w zakresie przejściowym między laminarnym a burzliwym (Rem do 1150) deacetylaza chitynowa nie ulega inaktywacji. Stwierdzono, że tworzenie się w układzie pęcherzy powietrza jest zjawiskiem bardzo niekorzystnym, prowadzącym do całkowitego zahamowania procesu. Wzrost lepkości mieszaniny reakcyjnej powodował spadek ilości zdeacetylowanych merów GlcNAc, a zatem zmniejszał wydajność procesu. Dezaktywacja termiczna enzymu okazała się czynnikiem najsilniej wpływającym na proces. Porównano także dane doświadczalne uzyskane w trakcie enzymatycznej deacetylacji chitozanu w reaktorze membranowym z modelem wykorzystującym zaproponowane równanie kinetyczne przy uwzględnieniu dezaktywacji termicznej enzymu, wykazując ich zgodność.

EN

Enzymatic deacetylation of chitosan is a process that can be an interesting alternative to chemical deacetylation. In both processes the linkage between the acetyl and amine groups in the N-acetylglucosamine units (GlcNAc) in chitosan in broken and the GlcNAc units are transformed into glucosamine units (GlcN) and acetic acid is released. Contrary to the chemical method, enzymatic deacetylation can be carried out under mild conditions and is not connected with parallel hydrolysis of the polymer chain. Additionally, by controlling the conditions of the enzymatic process, chitosan can be tailored to certain purposes. Chitin deacetylase from Absidia orchidis vel coerulea NCAIM F 00642 was used in the present work. This enzyme is not commercially available, and was separated from biomass by the author. Characterization of the enzyme showed that it has maximal activity at a pH of 4.0 (pH stability in the range from 1.0 to 9.0) and temperature 55°C. The model of thermal deactivation of chitin deacetylase at working temperature (50°C) was also proposed. Kinetics experiments indicated that enzymatic deacetylation of chitosan can be described by the Michaelis-Menten equation with competitive inhibition by acetic acid released during the deacetylation reaction.The kinetics equation was correlated with the specific activity of the enzyme, and this gave a much better approximation of experimental data than correlation with the enzyme concentration as in the original equation. In the next step of the work, the possibility of immobilization of chitin deacetylation on a carrier was investigated. It was shown that the best results were obtained for DEAE-Granocel activated with divinyl sulfone in alkaline conditions (pH 4.0 and T=45°). The kinetics of enzymatic deacetylation of chitosan by the immobilized enzyme was also described by the Michaelis-Menten equation. Unfortunately, the preparation lost its activity after the third usage. The last part of the work was dedicated to an investigation of the application of a membrane reactor for enzymatic deacetylation of chitosan. The parameters influencing the process were indicated. It was shown that chitin deacetylase stays active for laminar flow (up to Re = 1100) and for mixing in the range of the transition stage between laminar and turbulent flow (up to Re = 1150). The presence of air bubbles in the reaction mixture caused complete inactivation of chitin deacetylase. The increase in viscosity of the solution increased the stability of the enzyme, but also caused a decrease in the number of deacetylated GlcNAc units that influenced the effectiveness of the process. Thermal deactivation was the most important phenomenon that influenced enzymatic deacetylation of chitosan. The experimental data from the membrane reactor were compared to the models that used the propsed kinetics equation and/or lack of thermal deactivation of chitin deacetylase. The model with thermal deactivation gave a much better approximation than that without deactivation.

19

Efektywna synteza fluorofunkcyjnych (poli)siloksanów

63%

Maciejewski H. , Karasiewicz J. , Marciniec B.

|

2012

|

tom T. 57, nr 6

449-455

PL

Przeprowadzono badania nad syntezą fluorofunkcyjnych polisiloksanów opartą na procesach hydrosililowania fluorowanych eterów allilowych, których prekursorami były alkohole fluorowane. Porównano aktywność katalityczną kompleksów platyny i rodu w badanej reakcji i wyselekcjonowano najbardziej aktywny, bazujący na siloksylowym kompleksie rodu. Przeprowadzono także immobilizację wybranego kompleksu za pomocą czterech różnych cieczy jonowych i porównano aktywność katalityczną wytworzonych układów, w wielokrotnie powtórzonym cyklu reakcyjnym, przy użyciu takiej samej porcji katalizatora.

EN

Synthesis of fluorofunctional polysiloxanes based on hydrosilylation of fluoroalkyl ethers (precursors of the latter were fluoro alcohols) was studied. The most active catalyst, based on rhodium siloxide complex, was selected on the ground of a comparison of the catalytic performance of platinum and rhodium complexes. The rhodium complex was immobilized in four different ionic liquids and catalytic activities of the obtained systems were compared, while performing multiple reaction runs with the use of the same portion of catalyst.

20

Immobilizowane enzymy w bioremediacji środowisk zanieczyszczonych arenami

63%

Wojcieszyńska D. , Guzik U. , Nowak A. , Hupert-Kocurek K.

|

2011

|

tom R. 19, nr 2

53-61

PL

Związki aromatyczne, stanowiące duże zagrożenie dla organizmów żywych, rozkładane są przez mikroorganizmy do czterech głównych intermediatów: katecholu, kwasu protokatechowego, hydroksychinolu i kwasu gentyzynowego. Ze względu na dużą wrażliwość wolnych enzymów na zmienne warunki środowiska coraz częściej w technologiach oczyszczania ścieków stosuje się immobilizowane enzymy. Obecnie najpowszechniej stosowanym związkiem sieciującym jest glutaraldehyd, a nośnikami - membrany w układach przepływowych. Spośród enzymów stosowanych w technologiach oczyszczania terenów zdegradowanych, miedzy innymi zastosowanie znalazły immobilizowane: peroksydaza, lakaza oraz dioksygenazy katecholowe. Zaimmobilizowane enzymy odznaczają się większą stabilnością w czasie oraz odpornością na zmienne warunki środowiska. Ponadto stosowanie immobilizowanych enzymów pozwala na ich odzyskiwanie po zakończonym procesie, co obniża koszty bioprocesów.

EN

Aromatic compounds are considered as one of the most toxic and weakly degraded xenobiotics. They are degradated to four key intermediates such as catechol, protocatechuate, hydroxyquinol and gallic acid. Free enzymes are very sensitive to changing conditions of environment. That is a reason of immobilized enzymes very often use in technologies of sewage treatment. Glutaraldehyde is the most popular cross-linking agent and membranes in flow systems are the most often applied carrier in immobilization at present. The most often using enzymes in environmental treatment are immobilized peroxidise, laccase and catechol dioxygenases. Immobilized enzymes are more stable in time and resistant to environmental conditions changes. Immobilized enzymes use allow to recover them after finished process and, in the result, bioprocess cost reduction.