A potential application of a novel synergistic catalytic nanocluster system composed of biological enzymes and nanozyme in glycerol bioconversion

The integration of multimodal chemical/biocatalysis technology has provided a broad prospect in the efficiency of cascade reactions for a long time. Inspired by the intricate structure and superior efficiency of natural multi-enzyme systems, it is attractive for developing the next generation of high-performance orderly enzyme cascade biological platforms, combined with the catalase-like activity and immobilization properties of nanozymes. In our simple and convenient design, a biomimetic multi-enzyme hybrid nanocluster with excellent catalytic activity was synthesized by in-situ adsorption and immobilization of biological enzyme on nanozyme Fe3O4@OA. The combination of nanozyme Fe3O4@OA with single enzyme (concatenated alditol oxidase, catAldO) or double enzymes (catAldO and concatenated dihydroxy-acid hydrolyase, catDHAD) enjoys outstanding synergistic biocatalytic ability. Nanozyme Fe3O4@OA alternatives catalase to catalyze H2O2 cycle and regenerate O2, which implements the internal circulation of O2 → H2O2 → O2 system and accelerates the conversion of glycerol. It realized the high efficiency synergistic catalysis of nanozyme and biological enzyme successfully. In contrast to simple biocatalyst mixtures in solution, the prepared multienzyme hybrid resulted in the obvious improvements in activity for tandem reactions. The cascade bioactivity of the multienzyme complex was enhanced by the synergistic effect of the immobilization of nanozyme Fe3O4@OA, the opening of substrate channel between the enzyme and nanozyme, and the effective reduction of the transport distance among intermediate metabolites. In this study, it highlights the superiority of synergistic bioreactor integrated with nanoclusters contain Fe3O4@OA nanozyme and biological enzyme, realizing rapid recovery and multiple reusability of nanoclusters, and suggesting great application potential in multi-enzyme synergistic cascade catalysis.