A carbon-based bifunctional heterogeneous enzyme: toward sustainable pollution control

We present a study on an immobilized functional enzyme (IFE), a novel biomaterial with exceptional sustainability in enzyme utility, widely employed across various fields worldwide. However, conventional carriers are prone to eroding the active functional domain of the IFE, thereby weakening its intrinsic enzyme activity. Consequently, there is a burgeoning interest in developing next-generation IFEs. In this study, we engineered a carbon-based bifunctional heterogeneous enzyme (MIP-AMWCNTs@lipase) for the intelligent recognition of di(2-ethylhexyl)phthalate (DEHP), a common plasticizer. The heterogeneous enzyme contains a bifunctional structural domain that both enriches and degrades DEHP. We investigated its dual-response performance for the enrichment and specific removal of DEHP. The imprinting factor of the carrier for DEHP was 3.4, demonstrating selectivity for DEHP. The removal rate reached up to 94.2% over a short period. The heterogeneous enzyme exhibited robust activity, catalytic efficiency, and excellent stability under harsh environmental conditions, retaining 77.7% of its initial lipase activity after 7 cycles. Furthermore, we proposed a stepwise heterogeneous enzyme reaction kinetic model based on the Michaelis-Menten equation to enhance our understanding of enzyme reaction kinetics. Our study employs a dual-effect recognition strategy of molecular blotting and enzyme immobilization to establish a method for the removal of organic pollutants. These findings hold significant implications for the fields of biomaterials and environmental science.