Continuous Fluid Catalytic Reactor Constructed Based on In Situ Growth of MOF Immobilized Enzyme on Ordered Silk Fabric

Enzyme catalysis applications are limited because of their poor stability under extreme conditions. Using metal–organic frameworks (MOFs) as enzyme immobilization carriers efficiently solves this problem. However, MOFs easily agglomerate, are difficult to recover as a crystalline powder, and can only be used under continuous stirring, resulting in low reaction efficiencies. The use of immobilized enzymes for continuous fluid catalysis to improve catalytic efficiency remains challenging. At the same time, the spatial division of most immobilized enzyme porous materials is disordered, which leads to poor mass transfer efficiency and consequently low reaction rates. In this context, we want to construct a new type of reactor that solves the problem of enzyme stability by encapsulating enzymes in MOFs and then using low-cost and easily available silk fabric materials as immobilized carriers to load MOF immobilized enzymes. The ordered structure of silk fabric enhances substrate mass transfer, thereby improving the catalytic efficiency of the reactor. By comparing the mass transfer of a continuous fluid catalytic reactor with ordered silk fiber immobilized enzyme (OSCR) with that of a continuous fluid catalytic reactor with disordered silk fiber immobilized enzyme (DSCR) using crystal violet adsorption and catalytic process simulations, we demonstrated that the reaction efficiency in ordered spaces can be improved through mass transfer within each partition space. Finally, the reactor was used in the biotransformation of polydatin and demonstrated a high conversion of 98%, which was much higher than that of DSCR. This study revealed the enormous potential of ordered structure enzyme reactors in continuous fluid catalysis.