Relay run property of immobilized cholesterol oxidase on magnetic biochar for sterol removal

This study investigated the biocatalytic performance of immobilized cholesterol oxidase (CHOD) on magnetite-based carbon (MBC) for degrading cholesterol. The results showed that MBC-CHOD exhibited higher activity and good affinity towards substrate compared to free enzyme and other immobilized enzymes. Mass spectra analysis revealed that MBC-CHOD damaged the main structure of cholesterol, benefitting the further biological treatment. The study proposes a Fenton process mechanism by which H₂O₂ is transferred to free radicals such as ·OH under acidic conditions, promoting further substrate degradation. This suggests that MBC-CHOD has a relay run property leading to high degradation of cholesterol. Molecular docking indicates that cholesterol preferentially binds to TYR-28 residue and LYS-138 residue in CHOD through hydrogen bonds. Overall, MBC-CHOD proved to be a promising candidate for efficient and sustainable cholesterol degradation.