الفهرس 
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Abstract
Catalase is an oxidoreductase enzyme that plays an important role in quenching hydrogen peroxide that is produced as a byproduct of aerobic respiration.Thus catalase enzyme is considered as an antioxidant that protects the cell from oxidative stress. In addition, catalase has been used as a biocatalyst in many industrial applications such as pasteurization of milk and textile bleaching for hydrogen peroxide degradation.
However, there are some limitations in using catalase in industrial applications such as the inability to separate the enzyme from reaction mixture; hence the difficulty of reusing the enzyme many times that would be economically expensive.
So, enzyme immobilization has been developed that overcome the previously mentioned limitations. Many decades ago, scientists are trying to develop matrices that are able to enhance the stability and catalytic properties of the enzyme as well as the probability of reusing the enzyme more than one time in reaction.
The present work was designed to synthesize two novel matrices based on carrageenan/alginate beads as well as iron oxide magnetic nanoparticles, optimizing their loading capacity for the catalase enzyme and studying their enhancement for catalaytic, kinetic properties and reusability of the immobilized catalase. Finally, a comparison was made in order to evaluate best matrix that could be applied in the industrial scale.
To achieve this goal, carrageenan/alginate hybrid was treated with poly ethyleneimine followed by glutraldehyde to be suitable for the covalently immobilizing the catalase enzyme. On the other hand, iron oxide nanoparticles were synthesized by the co-precipitation technique, functionalized with epichlorohydrin and finally used to immobilize the catalase enzyme.
The two catalase immobilized matrices were subsequently subjected to the following studies of measuring their effects on the catalytic properties, kinetic parameters and reusability of the immobilized catalase.
In conclusion, the formulated iron oxide magnetic nanoparticles presented good results compared to the carrageenan/alginate matrix that would enable them to be a promising matrix for catalase immobilization and application in the industrial scale.
Key words: catalase, carrageenan/alginate beads, magnetic nanoparticles, immobilization.
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