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The occurrence of 17α-ethinylestradiol (EE2) in the environment and its removal have drawn special attention from the scientific community in recent years, due to its hazardous effects on human and wildlife around the world. Therefore, the aim of this study was to produce an efficient enzymatic system for the removal of EE2 from aqueous solutions. For the first time, commercial silica nanopowder and 3D fibrous chitinous scaffolds from Aplysina fistularis marine sponge were used as supports for horseradish peroxidase (HRP) immobilization. The effect of several process parameters onto the removal mechanism of EE2 by enzymatic conversion and adsorption of EE2 were investigated here, including system type, pH, temperature and concentrations of H 2 O 2 and EE2. It was possible to fully remove EE2 from aqueous solutions using system SiO 2 (HRP)-chitin(HRP) over a wide investigated pH range (5-9) and temperature ranges (4-45 °C). Moreover, the most suitable process conditions have been determined at pH 7, temperature 25 °C and H 2 O 2 and EE2 concentrations equaling 2 mM and 1 mg/L, respectively. As determined, it was possible to reuse the nanoSiO 2 (HRP)-chitin(HRP) system to obtain even 55% EE2 degradation efficiency after five consecutive catalytic cycles.

Enzymatic conversion of pharmaceutically active ingredients (API), using immobilized enzymes should be considered as a promising industrial tool due to improved reusability and stability of the biocatalysts at harsh process conditions. Therefore, in this study horseradish peroxidase was immobilized into sodium alginate capsules and then trapped into poly(vinyl chloride) electrospun fibers to provide additional enzyme stabilization and protection against the negative effect of harsh process conditions. Due to encapsulation immobilization, 100% of immobilization yield was achieved leading to loading of 25 μg of enzyme in 1 mg of the support. Immobilized in such a way, enzyme showed over 80% activity retention. Further, only slight changes in kinetic parameters of free ( K m = 1.54 mM) and immobilized horseradish peroxidase ( K m = 1.83 mM) were noticed, indicating retention of high catalytic properties and high substrate affinity by encapsulated biocatalyst. Encapsulated horseradish peroxidase was tested in biodegradation of two frequently occurring in wastewater API, sulfamethoxazole (antibiotic) and carbamazepine (anticonvulsant). Over 80% of both pharmaceutics was removed by immobilized enzyme after 24 h of the process from the solution at a concentration of 1 mg/L, under optimal conditions, which were found to be pH 7, temperature 25 °C and 2 mM of H 2 O 2 . However, even from 10 mg/L solutions, it was possible to remove over 40% of both pharmaceuticals. Finally, the reusability and storage stability study of immobilized horseradish peroxidase showed retention of over 60% of initial activity after 20 days of storage at 4 °C and after 10 repeated catalytic cycles, indicating great practical application potential. By contrast, the free enzyme showed less than 20% of its initial activity after 20 days of storage and exhibited no recycling potential.

• Polyamide 6 electrospun material was fabricated and characterised. • The horseradish immobilisation by adsorption and covalent binding was carried out. • The most efficient immobilisation conditions were: pH 7, 50 °C and 60 min of process. • The removal efficiencies were over 70% of Reactive Black 5 and 83% of Malachite Green. Despite many studies concerning dyes decolourisation, we propose a novel, cheap, eco-friendly and sustainable solution for highly effective dyes removal based on electrospun materials and immobilised enzyme. Our study provides proof-of-concept for the immobilisation of horseradish peroxidase (HRP) on polyamide 6 electrospun fibres by adsorption and covalent binding, and application for dyes decolourisation from imitating polluted sea waters. The highest relative activity of immobilised HRP was obtained after immobilisation performed at 50 °C and pH 7 for 60 min for adsorption method, as well as using 3% of glutaraldehyde concentration, 70 min of process time, 60 °C and pH 7 for covalent binding. Biocatalytic systems produced were found to possess high catalytic properties and were used for decolourisation of Reactive Black 5 and Malachite Green textile dyes from solutions imitating polluted sea waters, that is a novel approach for removal of pollutants from aqueous solutions. The highest decolourisation efficiencies of dyes were obtained after 60 min of treatment at pH 7 and temperature 25 °C and reached over 70%. In the future, the presented approach based on use of enzymes immobilised in decolourisation processes, might play significant role in industrial removal of dyes. [ABSTRACT FROM AUTHOR]

Glucose oxidase (GO X) and cholesterol oxidase (CO X) are enzymes with numerous practical applications in medicine and industry. Although various methods for improving of enzyme stability have been proposed, we present novel approach for enzyme compartmentalization using polyelectrolytes layers deposited on electrospun fibers made of poly(D,L-lactide- co -glycolide) and commercial membrane UFX5. Compartmentalization has a series of advantages over simple co-immobilization offering providing of suitable microenvironment for the immobilized enzymes, ensuring proper substrate/product channeling and improving stability and reusability of biomolecules. The biosystems produced via compartmentalization, resulted in higher conversion efficiency of model reaction at 45 °C and 65 °C compared to free enzymes as well as negative effect of hydrogen peroxide was minimalized after immobilization. Moreover, after 5 catalytic cycles, biosystems based on UFX5 membrane and HRP or GO X or CO X immobilized by compartmentalization reached efficiencies of 89% and 34%, respectively, with less than 10% enzyme elution from the support. Enzymes compartmentalized using ultrafiltration membrane showed also significant improvement of their biocatalytic productivity over repeated use, resulting in possible costs reduction of the desired process. Use of biosystems with electrospun fibers and co-immobilized enzymes resulted in enzyme elution of over 90% and very limited conversion efficiency. [Display omitted] • Novel approach for simultaneous compartmentalization of three enzymes on membranes. • Compartmentalization yield of over 90% was noticed. • Compartmentalized enzymes showed over 90% of conversion efficiency. • Over 40% improvement of enzyme stability against thermal and H 2 O 2 inactivation. • After 5 catalytic cycles UFX5/HRP/LbL/GO X retained 89% conversion efficiency. [ABSTRACT FROM AUTHOR]

Enzymatic conversion of pharmaceutically active ingredients (API), using immobilized enzymes should be considered as a promising industrial tool due to improved reusability and stability of the biocatalysts at harsh process conditions. Therefore, in this study horseradish peroxidase was immobilized into sodium alginate capsules and then trapped into poly(vinyl chloride) electrospun fibers to provide additional enzyme stabilization and protection against the negative effect of harsh process conditions. Due to encapsulation immobilization, 100% of immobilization yield was achieved leading to loading of 25 μg of enzyme in 1 mg of the support. Immobilized in such a way, enzyme showed over 80% activity retention. Further, only slight changes in kinetic parameters of free (Km = 1.54 mM) and immobilized horseradish peroxidase (Km = 1.83 mM) were noticed, indicating retention of high catalytic properties and high substrate affinity by encapsulated biocatalyst. Encapsulated horseradish peroxidase was tested in biodegradation of two frequently occurring in wastewater API, sulfamethoxazole (antibiotic) and carbamazepine (anticonvulsant). Over 80% of both pharmaceutics was removed by immobilized enzyme after 24 h of the process from the solution at a concentration of 1 mg/L, under optimal conditions, which were found to be pH 7, temperature 25 °C and 2 mM of H2O2. However, even from 10 mg/L solutions, it was possible to remove over 40% of both pharmaceuticals. Finally, the reusability and storage stability study of immobilized horseradish peroxidase showed retention of over 60% of initial activity after 20 days of storage at 4 °C and after 10 repeated catalytic cycles, indicating great practical application potential. By contrast, the free enzyme showed less than 20% of its initial activity after 20 days of storage and exhibited no recycling potential. [ABSTRACT FROM AUTHOR]