Publications by authors named "Milena Zuza"

The aim of this study was to investigate covalent immobilization of horseradish peroxidase (HRP) on magnetic nanoparticles (Mag) encapsulated in calcium alginate beads (MABs) for color degradation, combining easy and fast removal of biocatalyst from the reaction mixture due to its magnetic properties and strong binding due to surface alginate functional groups. MABs obtained by extrusion techniques were analyzed by optical microscopy, FEG-SEM and characterized regarding mechanical properties, magnetization and HRP binding. HRP with initial concentration of 10 mg/g was successfully covalently bonded on MABs (diameter ~1 mm, magnetite/alginate ratio 1:4), with protein loading of 8.

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Article Synopsis
  • The study focused on immobilizing alcalase, a protease, onto activated chitosan microbeads using various methods like adsorption, crosslinking, and covalent binding.
  • Covalent immobilization proved to be the most effective, achieving the highest enzyme activity and loading when using chitosan beads created by electrostatic extrusion.
  • The optimally produced alcalase-chitosan microbeads demonstrated significant effectiveness in hydrolyzing egg white and soy protein, achieving a high degree of hydrolysis after multiple uses in industrial conditions.
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The use of penicillin G acylase (PGA) covalently linked to insoluble carrier is expected to produce major advances in pharmaceutical processing industry and the enzyme stability enhancement is still a significant challenge. The objective of this study was to improve catalytic performance of the covalently immobilized PGA on a potential industrial carrier, macroporous poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) [poly(GMA-co-EGDMA)], by optimizing the copolymerization process and the enzyme attachment procedure. This synthetic copolymer could be a very promising alternative for the development of low-cost, easy-to-prepare, and stable biocatalyst compared to expensive commercially available epoxy carriers such as Eupergit or Sepabeads.

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  • Two anthraquinonic dyes, C.I. Acid Blue 225 and C.I. Acid Violet 109, were tested for decolorization using the horseradish peroxidase (HRP) enzyme to assess its effectiveness in treating wastewater.
  • The study analyzed how different factors like enzyme and hydrogen peroxide concentrations, temperature, dye concentration, and pH affected the decolorization process, finding optimal conditions for significant dye removal.
  • Results showed that under ideal settings, over 94% of Acid Violet 109 and around 89% of Acid Blue 225 were decolorized, indicating HRP's potential in reducing toxicity in wastewater treatments for similar dyes.
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Olive oil cake is a by-product from the olive oil processing industry and can be used for the lipase and protease production by Candida utilis in solid state fermentation. Different carbon and nitrogen sources were evaluated, and the results showed that the supplementation of the substrate with maltose and starch as carbon sources and yeast extract as a nitrogen source significantly increased the lipase production. The best results were obtained with maltose, whereas rather low lipase and protease activities were found with glucose and oleic acid.

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