Surface-Functionalized Fe3O4 Particle-Mediated Coimmobilization of Multienzyme for Cascade Biocatalytic Detoxification of Deoxynivalenol

Deoxynivalenol (DON), a ubiquitous mycotoxin contaminant in food and feedstuffs, has garnered global concern owing to its severe hazards to human and animal health. Here, magnetic Fe3O4 composites reinforced with polydopamine and polyethylenimine were employed for the coimmobilization of alcohol dehydrogenase (ADHM3) and aldo/keto reductase (AKRM5). This dual-enzyme reactor enabled the direct, one-step conversion of DON into nontoxic 3-epi-DON. Physicochemical characterization confirmed successful construction of the cascade biocatalytic system. The immobilized enzyme retained 85.9% relative activity retention compared to the free enzyme and maintained 63.8% of its initial activity after seven reuse cycles. Molecular dynamics simulations demonstrated that immobilization underpinned the experimentally observed improvement in enzyme thermal stability. Crucially, this coimmobilized system integrates the ADHM3 and AKRM5 cascade with the Fe3O4@PDA@PEI carrier, enabling one-step DON detoxification together with improved operational stability and magnetic recoverability, providing a high-efficiency pathway for mycotoxin management in the food industry.