Naslov
Stabilization of D-amino acid oxidase by immobilization

Autori
Tusić, Marko ; Česnik, Morana ; Petranović, Marko ; Findrik, Zvjezdana ; Vasić-Rački, Đurđa

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Applied Biocatalysis, 6th meeting of students and university professors, Book of Abstracts / Vasić-Rački, Đurđa ; Vrsalović Presečki, Ana ( - Zagreb : Pasanec d.o.o., 2010, 11-11

ISBN
978-553-6470-50-1

Skup
Applied Biocatalysis, 6th meeting of students and university professors

Mjesto i datum
Zagreb, Hrvatska, 09.06.2010

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
immobilization ; D-amino acid oxidase ; mathematical model

Sažetak
Amino acid oxidases (AAO) catalyze oxidative deamination of amino acids which is the reaction of major biotechnological and industrial interest [1]. They belong to a group of enzymes called oxidases and therefore require oxygen as one of the reactants. Oxygen can be continuously supplied to the reactor via aeration, which may promote very rapid and irreversible enzyme deactivation [2, 3]. Enzyme stabilization could be achieved e.g. via biocatalyst immobilization [4]. In the previous studies two D-amino acid oxidases: a commercial from porcine kidney, and non-commercial microbial enzyme isolated from Arthrobacter protophormiae, were tested as catalysts under different aeration conditions. It was found that aeration, as well as oxygen concentration in the case of D-amino acid oxidase from porcine kidney, negatively affects the enzyme, and it was therefore the purpose of this work to investigate different immobilization methods as a way of their stabilization. Immobilization was carried out by using the covalent method (Eupergit C) and entrapment in gel (Ca-alginate) as a physical method of immobilization. The results have shown that these two oxidases cannot be immobilized in Ca-alginate due to their low pI value which makes them negatively charged under the immobilization conditions (neutral pHs). Since alginate is negatively charged as well, the enzyme cannot stay entrapped in gel. The covalent immobilization on spherical particles of Eupergit C was successful. Both enzymes were immobilized in that manner, however porcine kidney enzyme was easier to immobilize because of its solid form. It was found that the porcine kidney enzyme was stabile under aeration conditions in this form and could be used repetitively. A. protophormiae oxidase was available as a suspension, a due to that the percentage of protein immobilization on Eupergit was much lower. The activity of this enzyme was lost during the immobilization procedure and it was not possible to achieve good results. Porcine kidney oxidase was further characterized. Enzyme kinetic parameters were estimated from the measurements carried out by the initial reaction rate method. Enzyme activity was determined under different aeration conditions and at different pH values. [1] Fisher L., D-amino acid oxidase in biotechnology, Recent Res Developm Microbiol 1998, 2: 295-317. [2] Golini P., Bianchi D., Battistel E., Cesti P., Tassinari R., Enzyme Microb Technol, 1995, 17: 324-329. [3] Bes T., Gomez-Moreno C., Guisan J.M., Fernández-Lafuente R., J Mol Catal, 1995, 98: 161-169. [4] Fernández-Lafuente R., Rodriguez V., Guisán J.M., Enzyme Microbial Technol, 1998, 23 (1-2):28-33.

Izvorni jezik
Engleski

Znanstvena područja
Biotehnologija

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