An engineering strategy from biomass support to a precision-recognition interface: amino acid-assisted imprinted polymers for protein adsorption.

An integrated strategy was developed to fabricate papain-imprinted polymers using magnetic biochar derived from waste tangerine peel. The biochar surface was modified with amino acids to improve protein affinity, and a biocompatible imprinting layer was subsequently formed through the mild polymerization of dual functional monomers. The optimized imprinted polymers exhibited high adsorption capacity (197.31 mg/g), strong selectivity (IF = 6.12), and robust reusability. Their utility was demonstrated through one-step selective purification of papain from complex samples, including crude commercial enzyme and spiked biological matrices. This work provides a sustainable strategy that combines biomass valorization with molecular imprinting for the purification of high-value enzymes in the food and biopharmaceutical industries.