Immobilization of horseradish peroxidase on ZnO nanowires/macroporous SiO₂ composites for the complete decolorization of anthraquinone dyes

Abstract

A zinc oxide (ZnO) nanowires/macroporous silicon dioxide composite was used as support to immobilize horseradish peroxidase (HRP) simply by in situ cross-linking method. As cross-linker was adsorbed on the surface of ZnO nanowires, the cross-linked HRP was quite different from the traditional cross-linking enzyme aggregates on both structure and catalytic performance. Among three epoxy compounds, diethylene glycol diglycidyl ether (DDE) was the best cross-linker, with which the loading amount of HRP with pI of 5.3 reached as high as 118.1 mg/g and specific activity was up to 14.9 U/mg-support. The mass loss of HRP cross-linked with DDE was negligible during 50-H leaching at 4 °C, and the thermal stability of the immobilized HRP was also quite good. The catalytic performance of immobilized HRP to decolorize anthraquinone dye was explored by using Reactive Blue 19 (RB 19) and Acid Violet 109 (AV 109) as model substrates. The results indicated that the immobilized HRP exhibited high decolorization efficiency and good reusability. The decolorization efficiency reached 94.3% and 95.9% for AV 109 and RB 19 within the first 30 Min, respectively. A complete decolorization of these two dyes has been realized within 2-3 H by using this new biocatalysis system.

Functionalized Materials as a Versatile Platform for Enzyme Immobilization in Wastewater Treatment

“…Many researchers have also used horseradish peroxide (HRP) in the degradation of organic dyes. For example, Sun et al [61] researched the immobilization of horseradish peroxidase on silica coated with zinc oxide. The results indicated that the proposed catalyst HRP/ZnO/SiO 2 exhibited a high decolorization efficiency and good reusability for anthraquinone dyes.…”

A robust and stable nano‐biocatalyst by co‐immobilization of chloroperoxidase and horseradish peroxidase for the decolorization of azo dyes

“…[39][40][41][42] More recently, ZnO nanowires were found to be capable of adsorbing bi-epoxy compound (diethylene glycol diglycidyl ether, DDE) that can react with amino groups on HRP; thus, an in situ cross-linking of HRP molecules was realized on the surface of ZnO nanowires. 43,44 This was quite different from the traditional method of CLEA preparation, in such a case the size of CLEAs of HRP could be limited because the amount and distribution of cross-linker was controlled by the structure of the nano-composite support.…”

Catalytic and Physicochemical Evaluation of a TiO2/ZnO/Laccase Biocatalytic System: Application in the Decolorization of Azo and Anthraquinone Dyes

“…ZnO and TiO 2 have been widely used as supports for enzyme immobilization [30][31][32][33]. For example, Movahedi et al [34] developed an easy and effective method of increasing the stability of lactoperoxidase (LPO) immobilized on ZnO nanoparticles (ZnO/LPO).…”