Characteristics of immobilized urease onto modified zirconium (IV) oxide via glutaraldehyde: kinetic, stability, and operational stabilities in bioreactors

Autor: Özlem Alptekin
Rok vydání: 2021
Předmět:
Zdroj: Chemical Papers. 76:749-761
ISSN: 2585-7290
0366-6352
Popis: This study aimed to obtain an efficient immobilized urease covalently immobilized onto modified zirconium (IV) oxide (ZrO2) that could serve in a dialysate regeneration system. For the first time, the characteristics of modified ZrO2 and immobilized urease preparations were studied in detail. The operational stabilities of urease in batch and continuous flow-type reactors were also compared. ZrO2 was sequentially modified with Piranha, 3-aminopropyl triethoxysilane, and glutaraldehyde (GA) followed by urease immobilization. The surface area of the carrier was increased by 29% after Piranha treatment. The bound urease onto modified ZrO2 was 3.9 mg g carrier−1. Optimum pH and temperature of free and immobilized ureases were found as 6.5 and 50 °C, and 7.0 and 60 °C, respectively. Following immobilization, the Km value of urease was increased from 2.7 ± 0.1 to 10.2 ± 0.4 mM and the Vmax value decreased from 51.6 ± 2.0 to 0.16 ± 0.02 U mg protein−1. The immobilized urease was 62, 35, and 46 fold more stable than the free urease at 50, 60, and 70 °C, respectively. It showed 90 and 58% of its initial activity at 4 °C and room temperature at the end of 12 days, respectively. The amount of removed urea was found to be 0.22 mg in a batch-type reactor and 0.39 mg in a continuous flow-type reactor at the end of 60 min. The immobilized urease onto ZrO2 has superior potential to use in artificial kidney machines due to significant contribution to reducing device weight.
Databáze: OpenAIRE
Externí odkaz: