1. Mesocellular silica foam as immobilization carrier for production of statin precursorsDino Skendrović, Mateja Primožič, Tonči Rezić, Ana Vrsalović Presečki, 2024, original scientific article Keywords: immobilization, aldolase, DERA, statins, mesoporous silica, pore size
Published in DKUM: 04.09.2024; Views: 72; Downloads: 8
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2. The immobilization of β-galactosidase on glass fiber rollsDarja Pečar, Katja Zečević, Andreja Goršek, 2023, original scientific article Abstract: The usability of glass fibers as immobilization support with a porous open structure was investigated. We developed a method to immobilize the enzyme β-galactosidase on special glass fiber rolls. The new method is simple, non-expensive and industrially applicable. Glutaraldehyde was used as a non-specific cross-linking agent for the covalent binding of β-galactosidase on modified glass fibers. The efficiency of immobilization was tested with the known hydrolysis of lactose. All experiments were performed in a continuous laboratory reactor. The influence of the reaction temperature (20, 25 and 30 °C), the substrate flow rate (1, 2 and 3 mL/min) and the pH of the reaction medium (6, 7 and 8) on the conversion was investigated. The reaction efficiency was monitored by measuring the glucose concentration with a spectrophotometer. High immobilization efficiency, enzyme activity and stability were obtained. The optimal reaction temperature, substrate flow rate and pH were found. The activity and stability of the enzyme entrapped on the glass fiber rolls remained almost unchanged during reuse, which is promising for potential industrial applications.
Keywords: beta-galaktosidase, immobilization, glass fiber, lactose
Published in DKUM: 17.04.2024; Views: 189; Downloads: 17
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3. Transglutaminase in foods and biotechnologyKatja Vasić, Željko Knez, Maja Leitgeb, 2023, review article Keywords: transglutaminase, industrial enzyme, protein-modifying enzyme, crosslinker, antibody– drug conjugation, immobilization
Published in DKUM: 06.12.2023; Views: 563; Downloads: 22
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5. Chemical modification and characterization of poly(ethylene terephthalate) surfaces for collagen immobilizationMioara Drobota, Zdenka Peršin Fratnik, Lidija Fras Zemljič, Tamilselvan Mohan, Karin Stana-Kleinschek, Aleš Doliška, Matej Bračič, Volker Ribitsch, Valeria Harabagiu, Sergiu Coseri, 2013, original scientific article Abstract: The functionalization of poly(ethylene terephthalate) (PET) surface films by reactions with multifunctional amines such as triethylenetetramine (TETA), and tetraethylenepentamine (TEPA) was investigated. For the functionalization of PET films surface we used a new way of treatment, a 'sandwich model'. Physical-chemical properties of functionalized PET films were analysed. Qualitative and quantitative determination of the introduced amine groups were examined by means of Fourier Transform Infrared Attenuated Total Reflexion(FTIR - ATR), X-ray photoelectron spectroscopy (XPS), and potentiometric titration. Gained wetting properties were determined by using contact angle measurements and thoroughly analysed by acid-base approach. In addition, surface topography was investigated by atomic force microscopy (AFM). The amount of the introduced amino groups after TETA incorporation has been found to be two times higher as compared to TEPA. Wetting properties were significantly improved after aminolysis. Surface free energy was higher for PET - TETA treated film than that observed for PET - TEPA treated which is in accordance with titration results. The collagen immobilization onto PET treated films was evidenced by using AFM and subsequently by using XPS.
Keywords: PET, aminolysis, AFM, collagen immobilization
Published in DKUM: 03.04.2017; Views: 1532; Downloads: 418
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6. Silica aerogels as support for lipase catalyzed esterifications at sub- and supercritical conditionsZoran Novak, Maja Leitgeb, Vlasta Krmelj, Željko Knez, 2003, original scientific article Abstract: The enzymes (lipases from Candida rugosa and porcine pancreas) were immobilized on silica aerogels by sol-gel procedure followed by supercritical drying with CO2. Such immobilized enzymes were used as biocatalysts for esterification in supercritical CO2 and near critical propane at 40 °C and 100 bar. It was found out that the initial reaction rates in propane rose two to three times in comparison with the same reaction, catalyzed by free lipase. SC CO2 deactivated the non-immobilized lipase in reaction mixture while with the immobilized enzyme the conversion was 35%. The initial reaction rates in propane were 20 times higher than in water medium due to the properties of propane as a medium for esterification of fatty acids.
Keywords: chemical processing, biotechnology, esterification, immobilization of enzymes, supercritial CO2, propane, lipases, supercritical CO2 drying
Published in DKUM: 01.06.2012; Views: 1880; Downloads: 29
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