Nanoporous Phyllosilicate Assemblies for Enzyme Immobilization.

Abstract

Physical/chemical adsorption is well-known as a facile and effective method for enzyme immobilization, while ideal adsorbents with a high structural stability, high loading capacity, and low leaching ratio are still under exploration. In this study, nanoporous assemblies of two-dimensional (2D) copper phyllosilicate (L-CuSiO3) are prepared as an adsorbent to immobilize horseradish peroxidase (HRP) for phenol-containing wastewater treatment. Specifically, the robust chemical bonds of Si-O-Si and Si-O-Cu in L-CuSiO3 ensure its superior structural stability; the well-developed porous structure endows L-CuSiO3 assemblies with a high specific surface area of 611.7 cm3 g-1, which enables a fast and high enzyme loading of 140 mg g-1 within 4 h, and the well-distributed Cu(II) ions ensure the stable attachment of enzyme through Cu(II)-arginine (in HRP) coordination with a leaching ratio less than 10%. Meanwhile, the scaling assembly of L-CuSiO3 renders the resultant biocatalyst (HRP-loaded L-CuSiO3 assemblies) ease-of-recycling performance. Given the above features, the HRP-loaded L-CuSiO3 assemblies exhibit a better stability and 2-fold higher activity by contrast with HRP adsorbed on conventional mesoporous SiO2 and SiO2 nanoparticles, and it also acted as an efficient bioreactor in the application of catalytical removal of phenol pollutants from wastewater. Our L-CuSiO3 assemblies show great potential in immobilization of enzymes for industrial biocatalysis.