Potential and challenges of enzyme incorporated nanotechnology in dye wastewater treatment: A review

Enzymes are known to catalyze reactions at high efficiency, operate at milder conditions and are biodegradable. Due to enzyme limitations such as sensitivity to environmental conditions, enzyme immobilization is often used. The commonly employed immobilization methods include adsorption, entrapment, covalent attachment and cross-linking. Many research works have now focused on the immobilization of enzymes on nanoscale support due to the higher surface area to volume ratio, effective enzyme loading, significantly enhanced mass transfer efficiency and minimization of diffusional problems. The application of enzyme incorporated nanotechnology in the treatment of dye wastewater is thus, of high interest. Therefore, this paper has critically reviewed (1) the current technologies available for dye wastewater treatment; (2) different methods utilized for enzyme immobilization; and (3) the application and performance of enzyme incorporated nanotechnology for dye wastewater treatment. We identified that there is high potential for enzyme incorporated nanotechnology to be implemented in dye wastewater treatment due to the high decolorization performance (e.g. laccase immobilized on Fe₃O₄/SiO₂ nanoparticles achieved 99% decolorization of Procion Red MX-5B in 20min). We have also identified the key challenges faced by enzyme incorporated nanotechnology in dye wastewater treatment that includes: (i) realization of lab scale experiments to industrial applications; (ii) lack of understanding of enzymes incorporated nanotechnology; (iii) recovery of immobilized enzyme; (iv) synthesis of hybrid nanoflowers; and (v) sustainability of the nanomaterials used.