Dihydroflavonol 4-reductase immobilized on Fe3O4-chitosan nanoparticles as a nano-biocatalyst for synthesis of anthocyanidins

Dihydroflavonol 4-reductase (DFR) is a crucial enzyme involved in anthocyanidin biosynthesis pathway in plants. Here, we successfully immobilized the recombinant DFR protein onto Fe3O4-Chitosan (Fe3O4-CS) nanocarrier based on covalent bonding. The Fe3O4-CS-immobilized DFR enzyme were characterized and its catalytic function for anthocyanidins synthesis in vitro was confirmed. The immobilized enzyme enhanced thermal and acid stabilities and tolerances to the inhibitions of Zn2+, Cu2+, Fe2+and several organic solvents, remained 75 % initial activities after 25 days of storage, other than relatively lower catalytic yield of anthocyanidins. In this work, we developed a new recyclable nano-immobilized biocatalyst for the catalytic synthesis of anthocyanidins.