Microperoxidase-11-NH2-FSM16 biocatalyst: A heterogeneous enzyme model for peroxidative reactions

FSM16 mesoporous silicate and its chemically modified samples were synthesized. Then the relevant nanobiocatalysts consisting of Fe(III)protoporphyrin(IX) (Hemin, Fe(III)PPIX), microperoxidase-11 and horseradish peroxidase were obtained via direct immobilization of the biocatalysts in the nanopores of amine modified FSMs. The prepared catalysts were characterized by XRD, ASAP and diffuse reflectance UV/Vis techniques. The performances of the obtained peroxidase model nanostructures were evaluated by some typical test reactions, such as oxidation of ABTS, ortho-methoxyphenol (guaiacol) and peroxidatic synthesis of indophenol and N-antipyryl-p-benzoquinoneimine. Kinetic parameters including initial reaction rates, rate constants, Vmax, turnover number, Michaelis constant and catalytic efficiency were obtained and compared to those of Fe(III)PPIX/MCM41 (as a blank) and homogeneous native horseradish peroxidase (HRP). Results showed that MP-11-NH2-FSM16 nanobiocatalyst is able to mimic horseradish peroxidase with a Km value of 55.45 ± 1.29 μM with respect to ABTS and guaiacol (as the reducing substrates of HRP). The prepared nanobiocatalysts with high catalytic efficiencies about 108 M−1 min−1 showed high peroxidatic activity for oxidation and conversion of aromatic substrates.

Graphical abstractNanobiocatalysts consisting of hemin, microperoxidase-11 and peroxidase were obtained by immobilization of biocatalysts on amine-modified FSM16. Performances of these peroxidase models examined by peroxidatic and biotransformation reactions. Results showed that MP-11/NH2-FSM16 mimics HRP (Km ∼ 55.45 ± 1.29 μM for ABTS and guaiacol), meaning that these heterogeneous models with high catalytic efficiencies (108 M−1 min−1) are applicable for oxidation and peroxidative conversion of aromatic substrates. Figure optionsDownload full-size imageDownload as PowerPoint slide