A chemo-biocatalyst based on glutamate oxidase-integrated biomimetic trimanganese tetraoxide as cascade composite nano-catalyst for synthesis of α‑Ketoglutaric acid

The combination of chemo- and biocatalysts to perform one-pot synthetic route has presented great challenges for decades. Herein, glutamate oxidase (GLOX) and trimanganese tetraoxide (Mn 3 O 4 ) nanocrystals were combined for the first time by one-step biomineralization to construct a mimic multi-enzyme system ( [email protected] 3 O 4 ) for chemoenzymatic synthesis of α‑ketoglutaric acid (α‑KG). Mn 3 O 4 not only served as a support for the enzyme immobilization, but also contributed its catalytic activity to co-operate with natural enzymes for the cascade reactions . The as-synthesized chemo-enzyme catalysts with directly contacted catalytic sites of the enzyme and inorganic catalyst maximizes the substrate channeling effffects for in situ rapid decomposition of the oxidative intermediate, H 2 O 2 , during the enzymatic oxidation of sodium glutamate, thus relieving the inhibition of H 2 O 2 accumulation for GLOX. Benefiting from the excellent stability and reusability of [email protected] 3 O 4 , a nearly 100% conversion (99.7%) of l -glutamate to α-KG was achieved, over 4.7 times higher than that of the free GLOX system (21.2%). This work provides a feasibility for constructing a high-performance chemo-enzyme catalyst for cascade catalysis, especially for those reactions with toxic intermediates.