Enzymatic catalytic processes possess great potential in chemical manufacturing, including pharmaceuticals, fuel production and food processing. However, the engineering of enzymes is severely hampered due to their low operational stability and difficulty of reuse. Here, we develop a series of stable metal-organic frameworks with rationally designed ultra-large mesoporous cages as single-molecule traps (SMTs) for enzyme encapsulation. With a high concentration of mesoporous cages as SMTs, PCN-333(Al) encapsulates three enzymes with record-high loadings and recyclability. Immobilized enzymes that most likely undergo single-enzyme encapsulation (SEE) show smaller Km than free enzymes while maintaining comparable catalytic efficiency. Under harsh conditions, the enzyme in SEE exhibits better performance than free enzyme, showing the effectiveness of SEE in preventing enzyme aggregation or denaturation. With extraordinarily large pore size and excellent chemical stability, PCN-333 may be of interest not only for enzyme encapsulation, but also for entrapment of other nanoscaled functional moieties.
This work was supported as a part of the Methane Opportunities for Vehicular Energy (MOVE) Program under the Award Number DE-AR0000249, as part of the Center for Clean-Energy-Related Gas Separation, an Energy Frontier Research Center funded by the U. S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences and as part of N000141310753 supported by the Office of Naval Research. Use of the Advanced Photon Source, an Office of Science User Facility operated for the U. S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, was supported by the U. S. DOE under Contract No. DE-AC02-06CH11357. The structure characterization by PXRD and TEM was supported by the Swedish Research Council (VR), the Swedish Governmental Agency for Innovation Systems (VINNOVA) and the Knut & Alice Wallenberg Foundation through a grant for purchasing the TEM and the project grant 3DEM-NATUR. We also thank Zhenggang Xu and Dr Qian Peng from the Supercomputing Facility at Texas A&M University and Laboratory for Molecular Simulation for offering access to computing time and valuable discussions; Dr Hung-Jue Sue and Dr Peng Liu from Mechanical Engineering at Texas A&M University for Thermogravimetric analysis; Dr Hansoo Kim in the Microscopy and Imaging Center at Texas A&M University for the TEM-DEX elemental mapping; Lizzie West for organizing other manuscript related works.
Crystallographic Information Files for PCN-332 and PCN-333.