Abstract
Aflatoxin B1 (AFB1) is a potent mycotoxin threatening food and feed safety. Here, we report the identification and characterization of a Bacillus safensis-derived multicopper oxidase (BsaMCO) capable of efficient AFB1 detoxification. Recombinant BsaMCO exhibited robust in vitro activity, achieving >78% degradation of AFB1 under 24 h incubation at 37 °C. Optimization experiments revealed that enzyme concentration, pH, temperature, metal ions, and electron acceptors significantly influenced degradation efficiency, defining an operational window suitable for practical applications. LC–MS profiling suggested the presence of transformation products tentatively consistent with oxidative demethylation to aflatoxin P1 (AFP1) and with the formation of AFG2a-like products through subsequent hydration- and oxidation-related transformations. Molecular docking and 100 ns all-atom molecular dynamics (MD) simulations demonstrated stable binding of AFB1 in the T1 copper pocket. Van der Waals and electrostatic interactions, together with a persistent hydrogen bond at Gly323, facilitated single-electron transfer through the intramolecular T2/T3 copper cluster. Principal component and Gibbs free energy analyses confirmed a low-energy, stable conformational ensemble. HepG2 cell assays indicated that BsaMCO-degraded products substantially reduced cytotoxicity and apoptosis compared with native AFB1. Simulated feed experiments further validated enzymatic AFB1 degradation, with approximately 53% reduction after 24 h. Collectively, these findings establish BsaMCO as a safe and effective biocatalyst for AFB1 detoxification, providing mechanistic, structural, and cellular evidence supporting its application in food and feed safety.