Co-immolization of lipase and bimetallic Cu/Mn aminoclay nanozyme onto montmorillonite for spatially synergistic conversion of p-nitrophenyl esters

The detoxification and valorization of toxic p-nitrophenol (p-NP) and its ester derivatives into high-value p-aminophenol (p-AP) present a significant challenge in green chemistry. This work addresses this challenge by developing a hybrid catalyst through the co-immobilization of lipase and a novel bimetallic Cu/Mn aminoclay nanozyme (CMAC) onto montmorillonite (Mt). The key innovation lies in the multifunctional design of CMAC, which serves not only as a highly active laccase-mimicking nanozyme but also as an intrinsic immobilization matrix for lipase, while the Mt support simultaneously prevents nanozyme aggregation and enhances structural stability. This integrated lipase-CMAC@Mt. platform enables efficient substrate channeling, whereby the p-NP intermediate generated from lipase-catalyzed hydrolysis of p-NPP is directly reduced by adjacent CMAC to p-AP, minimizing intermediate accumulation and overcoming diffusion limitations. As a result, the hybrid catalyst achieves efficient one-pot conversion of p-NPP to p-AP, without requiring harsh reagents or intermediate separation. Remarkably, it exhibits exceptional reusability (76.8 % activity retention after 10 cycles) and storage stability (82.4 % activity retained over 30 days), substantially outperforming conventional free enzyme systems. This study demonstrates a strategic bio-nano synergy that combines the specificity of enzymes with the robustness of nanozymes, offering a scalable and economically viable platform for simultaneous toxic waste elimination and resource recovery.