Immobilized Soybean Peroxidase Hybrid Biocatalysts for Efficient Degradation of Various Emerging Pollutants.

Rana Morsi,Khadega A Al-Maqdi,Iltaf Shah,Muhammad Bilal,Hafiz M N Iqbal,Syed Salman Ashraf,Abbas Khaleel

doi:10.3390/biom11060904

Rana Morsi, Khadega A Al-Maqdi + Show 5 more

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https://doi.org/10.3390/biom11060904

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Abstract

In the present study, soybean peroxidase (SBP) was covalently immobilized onto two functionalized photocatalytic supports (TiO2 and ZnO) to create novel hybrid biocatalysts (TiO2-SBP and ZnO-SBP). Immobilization caused a slight shift in the pH optima of SBP activity (pH 5.0 to 4.0), whereas the free and TiO2-immobilized SBP showed similar thermal stability profiles. The newly developed hybrid biocatalysts were used for the degradation of 21 emerging pollutants in the presence and absence of 1-hydroxy benzotriazole (HOBT) as a redox mediator. Notably, all the tested pollutants were not equally degraded by the SBP treatment and some of the tested pollutants were either partially degraded or appeared to be recalcitrant to enzymatic degradation. The presence of HOBT enhanced the degradation of the pollutants, while it also inhibited the degradation of some contaminants. Interestingly, TiO2 and ZnO-immobilized SBP displayed better degradation efficiency of a few emerging pollutants than the free enzyme. Furthermore, a combined enzyme-chemical oxidation remediation strategy was employed to degrade two recalcitrant pollutants, which suggest a novel application of these novel hybrid peroxidase-photocatalysts. Lastly, the reusability profile indicated that the TiO2-SBP hybrid biocatalyst retained up to 95% degradation efficiency of a model pollutant (2-mercaptobenzothiazole) after four consecutive degradation cycles.

Highlights

Emerging pollutants (Eps) are a new class of organic chemicals that are increasingly detected in water bodies
The current study was carried out to expand the potential application of peroxidases by immobilizing soybean peroxidase (SBP) onto two photocatalytic supports (TiO2, ZnO) to address the limitations associated with scalability and non-reusability of these enzyme-based approaches
They were degraded slightly (

Summary

Introduction

Emerging pollutants (Eps) are a new class of organic chemicals that are increasingly detected in water bodies. Though the concentration of Eps in the environmental matrices ranges from ng/L to few hundreds of μg/L [4,5], these are recognized to cause serious ecological and physiological threats such as interfering with the endocrine system, reproductive impairments, physical abnormalities, congenital disorders, and feminization of some fish species [6]. Due to these undesirable and deleterious effects on human health and the ecosystem, research on emerging pollutants has prioritized the focus of researchers and environmental engineers around the globe.

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