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Wykorzystanie metody enzymatycznej do badania rozpuszczalności tlenu w ciekłych perfluorozwiązkach

Pilarek M., Zygmuntowicz J., Dąbkowska K., Moniuk W.

Inżynieria i Aparatura Chemiczna

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2013

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Nr 5

467--468

PL

Opracowano metodę enzymatyczną pomiaru stężenia 02 w perfluorodeka- linie (PFD) poprzez wykorzystanie układu następczych reakcji katalizowanych przez oksydoreduktazy. Metodyka pozwala określić stężenie 02 w próbie PFD o objętości rzędu mikro litrów. Wyznaczono wartości objętościowych współczynników wnikania masy w fazie gazowej i ciekłej w dwufazowym układzie PFD-tlen/powietrze.

EN

An enzymatic method for the determination of 02 solubility in perfluoro- decalin (PFD) and based on the system of two reactions catalysed by oxi- doreductases was elaborated. The proposed method enables one to determine the 02 concentration in PFD microliter-scale samples. Volumetric mass transfer coefficients in gas and liquid phases for the PFD-oxygen/air two-phase system were calculated.

2

Carbon nanotubes chemically derivatized with redox systems as mediators for biofuel cell applications

Bilewicz R., Nazaruk E., Żelechowska K., Biernat J. F., Stolarczyk K., Roberts K. P., Ginalska G., Rogalski J.

Biocybernetics and Biomedical Engineering

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2011

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Vol. 31, no. 4

17-30

EN

The aim of this study was designing of nanostructured bioelectrodes and assembling them into a biofuel cell with no separating membrane. Carbon nanotubes (CNTs) chemically connected with residues of typical mediators, i.e. ferrocene (Fc) and 2,2'-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) deposited on glassy carbon electrodes (GCE) were found useful as mediators for the enzyme catalyzed electrode processes. The electrodes were in turn covered with glucose oxidase from Aspergillus niger AM-11 and laccase from Cerrena unicolor C-139, respectively, incorporated in a liquid-crystalline matrix. The nanostructured electrode coating with the cubic phase film containing enzymes acted as the catalytic surface for the enzymatic reactions that is oxidation of glucose at anode and reduction of oxygen at cathode. For the system with mediators anchored to CNTs the catalysis was almost ten times more efficient than on bare GCE electrodes: catalytic current of glucose oxidation was 1 mAcm-2 and oxygen reduction current exceeded 0.6 mAcm-2. The open circuit voltage of the biofuel cell was 0.43 V. Application of the carbon nanotubes increased maximum power output of the constructed biofuel cell to 100 \miWcm-2 without stirring the solution. It is ca. 100 times more efficient than using the same bioelectrodes without nanotubes on the electrode surface.

3

Enzymatic pre-treatment of cotton. Part 2. Peroxide generation in desizing liquor and bleaching

Anis P., Davulcu A., Eren H. A.

Fibres & Textiles in Eastern Europe

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2009

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Vol. 17, no. 2 (73)

87--96

EN

The objective of this study was to utilise desizing liquors of starch-sized fabrics using glucoseoxidase enzymes for bleach to produce hydrogen peroxide from glucose units of the starch removed; glucoseoxidase enzymes are efficient only at high glucose doses. In the first part of this paper, glucose generation in a desizing bath was discussed and an optimum recipe was obtained with an amyloglucodidase/pullanase mixture enzyme . In this study, process optimisation for the glucose oxidase enzyme was undertaken in order to generate hydrogen peroxide in the desizing liquor and then bleaching with the peroxide generated . Results indicated that sufficient hydrogen peroxide, about 800 mg l-1, could be generated to perform successful enzymatic bleaching; however, the bleaching was compatible with the conventional peroxide type only in the alkali pH range. The maximum whiteness obtained by enzymatic treatment was 73.8 Stensby degree, whereas the whiteness of the conventionally treated fabric was 79.4 Stensby degree.

PL

Przedmiotem badań była utylizacja kąpieli usuwającej klejonkę materiałów impregnowanych skrobią poprzez enzymy glikozydazy stosowane do bielenia w celu wydzielenia nadtlenku wodoru z glukozy zawartej w usuwanej skrobi. Enzymy glukozydazy są wydajne tylko przy dużych ilościach glukozy. W pracy przedyskutowano wydzielanie glukozy w kąpieli usuwającej klejonkę i określono optymalną procedurę stosowania mieszaniny enzymów amyloglukodidaze/pullanaze. W pracy przeprowadzono optymalizację działania enzymu glukozydazy w celu wydzielenia nadtlenku wodoru w roztworze usuwającym klejonkę a następnie bielenia tkaniny przez wydzielony nadtlenek. Wyniki badań wskazują, że dostateczna ilość nadtlenku wodoru ok. 800mg/l może być wydzielona dla uzyskania korzystnego enzymatycznego bielenia. Jednakże bielenie to jest porównywalne z konwencjonalnym bieleniem za pomocą nadtlenku tylko w zakresie pH odpowiadającemu zasadowości roztworu. Maksymalna biel uzyskana w wyniku enzymatycznej obróbki wynosiła 73,8 stopni Stensby’a podczas gdy biel tkanin poddanych konwencjonalnej obróbce wynosiła 79,4 stopni Stensby’a.

4

Fluorescence detection of biological objects with ultraviolet and visible light-emitting diodes

Kurilcik N., Vitta P., Zukauskas A., Gaska R., Ramanavicius A., Kausaite A., Jursenas S.

Optica Applicata

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2006

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Vol. 36, nr 2-3

193-198

EN

Recent progress in fabrication of semiconductor light emitting diodes (LEDs) allows these devices to be used for excitation of fluorescence of aromatic amino acids and other biofluorophores. In our work, a deep-UV UVTOPTM LED (280 nm) developed by Sensor Electronic Technology, Inc., was used for fluorescence characterisation of natural protein fluorophores in enzyme glucose oxidase (GOx) and in Bacillus subtilus dry spores (B. subtilus). A longer-wavelength Nichia LED (375 nm) and high-power LuxeonTM LED (450 nm) were used for fluorescence detection of enzyme cofactors. Combined spectral and fluorescence lifetime measurements using selective LED excitation enabled us to recognise the impact of specific autofluorophores in complex biological systems. Inexpensive LED-based fluorescence detectors can be used in designing biosensors and detect-to-warn systems.

5

Potentiometric tungsten electrodes with enzymes immobilised by the sol-gel technique

Przybyt M.

Materials Science

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2003

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Vol. 21, No. 4

417-429

EN

The application of sol-gel transitions in development of potentiometric enzyme electrodes with urease, glucose oxidase and tyrosinase is described. Urease and glucose oxidase electrodes showed features of typical potentiometric electrodes with the response modified by the change of pH. The slopes of calibration curves in semilogarithmic coordinates were lower than the Nernstian values and the dynamic ranges were narrow for both electrodes. The tyrosinase electrode shows response to mono- and o-diphenols. The response of this electrode is not connected with the pH changes. The mechanism of the response of the tyrosinase electrode is discussed; it is proposed that the potential changes reflect the redox state of the enzyme. The electrode responds to reactant concentration (phenol, catechol and some others) even at concentrations 210-6 M. Such a high sensitivity makes the electrode a promising candidate for application in detecting traces of phenols.

6

Behaviour of glucose oxidase during formation and ageing of silica gel studied by fluorescence spectroscopy

Przybyt M.

Materials Science

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2003

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Vol. 21, No. 4

397-416

EN

Glucose oxidase was entrapped in silica gels obtained by the sol-gel process with the retention of a part of its activity. The stability of the enzyme molecule during the sol-gel transition and ageing of the wet gel was followed by the measurement of fluorescence of tryptophan and flavin adeninedinucleotide (FAD). The results indicate unfolding and denaturation of the enzyme protein caused by the changes of microenvironment inside gel, presence of ethanol, decomposition of FAD and photosensitised oxidation of tryptophan by FAD. Among the products of FAD decomposition, alloxazine derivatives were identified through their specific fluorescence characteristics. The results of the observation of the fluorescencje variation and activity assay of the gel are in good agreement. The experiments with the dried gel indicato that illumination is not necessary to sensitise the reaction of oxidation of tryptophane by FAD although In the presence of light the effectiveness of this process is higher. Presumably the decomposition of FAD and tryptophan is not only induced by light but also by the paramagnetic (with free radical character) defects in the gel matrix. This reaction is enhanced by the presence of glucose and depends also on pH of the buffer used in the gel preparation. The products of the enzyme degradation are easily washed out from the gel. Leaching of active enzyme from the gel was also observed.