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- Title
Removal of Selected Azo Dyes and Phenolic Compounds via Tyrosinase Immobilized Magnetic Iron Oxide Silver Nanoparticles.
- Authors
Yavaşer, Rukiye; Aktaş Uygun, Deniz; Karagözler, Arife Alev
- Abstract
Tyrosinase is a well-known oxidoreductase for removal of dyes and phenolic compounds regarded as hazardous and toxic substances concerning environmental issue and health of living systems. To develop an efficient, practical and reusable biocatalyst to remove these pollutants, covalent immobilization of Agaricus bisporus tyrosinase onto 3-mercaptopropionic acid modified silver-coated Fe3O4 nanoparticles through EDC/NHS chemistry was employed. Characterization techniques involving Fourier transform infrared spectroscopy, transmission electron microscopy–energy dispersive X-ray mapping and electron spin resonance confirmed the synthesis and immobilization success. The amount of immobilized tyrosinase was calculated to be 216.6 ± 1.250 mg per one gram of nanoparticles. Enzymatic characterization of free and immobilized tyrosinase was elucidated using two substrates, l-catechol and l-tyrosine to evaluate the differences in enzyme behavior towards different substrates. Optimum pH was 7.0 and 6.5 with l-catechol and l-tyrosine, respectively, for free and immobilized enzyme. Optimum temperatures were determined to be 45 °C and 35 °C for free and immobilized tyrosinase with l-catechol respectively, whereas with l-tyrosine, maximum activity was observed at 45 °C for both forms of tyrosinase. The affinity between tyrosinase and the substrates increased about 1.4 fold after immobilization. Immobilized tyrosinase preserved 48.9% of its initial activity after six reuses. Residual activity of immobilized tyrosinase was 68.3% after 84 days of storage whereas it was only 45.8% for free enzyme. Immobilized tyrosinase was able to decolorize azo dyes [Reactive Green 19 (36.9%) and Congo Red (95.0%)] and remove phenolic compounds [phenol (82.5%), Bisphenol F (65.0%), Bisphenol A (39.3%), p-cresol (73.1%), phenyl acetate (92.3%), 3-chlorophenol (50.5%), 4-chlorophenol (87.8%)] from aqueous solutions. Electrochemical behavior of immobilized tyrosinase as a catechol biosensing material was also demonstrated by cyclic voltammetry (CV). This work contributes to the bioremediation strategies that could be applied for removal of azo dyes and phenolic compounds from wastewaters through an environmentally-safe manner.
- Subjects
BISPHENOL A; IRON oxide nanoparticles; BISPHENOLS; FOURIER transform infrared spectroscopy techniques; PHENOL oxidase; PHENOLS; AZO dyes
- Publication
Catalysis Letters, 2023, Vol 153, Issue 5, p1265
- ISSN
1011-372X
- Publication type
Article
- DOI
10.1007/s10562-022-04087-z