The Chemistry and Applications of Metal–Organic Frameworks (MOFs) as Industrial Enzyme Immobilization Systems

Abstract

Enzymatic biocatalysis is a sustainable technology. Enzymes are versatile and highly efficient biocatalysts, and have been widely employed due to their biodegradable nature. However, because the three-dimensional structure of these enzymes is predominantly maintained by weaker non-covalent interactions, external conditions, such as temperature and pH variations, as well as the presence of chemical compounds, can modify or even neutralize their biological activity. The enablement of this category of processes is the result of the several advances in the areas of molecular biology and biotechnology achieved over the past two decades. In this scenario, metal–organic frameworks (MOFs) are highlighted as efficient supports for enzyme immobilization. They can be used to ‘house’ a specific enzyme, providing it with protection from environmental influences. This review discusses MOFs as structures; emphasizes their synthesis strategies, properties, and applications; explores the existing methods of using immobilization processes of various enzymes; and lists their possible chemical modifications and combinations with other compounds to formulate the ideal supports for a given application.

Directed Immobilization of PETase on Mesoporous Silica Enables Sustained Depolymerase Activity in Synthetic Wastewater Conditions

“…Recent examples include applications of engineered lipases toward biofuel production − and enantiopure synthesis of important drug precursor molecules . Immobilization has been shown to further enhance the versatility of enzymes in industrial contexts. ,− Discovery and engineering of plastic degrading enzymes have shown that biodegradation of microplastics in the wastewater treatment system is a strategy with high potential for success . Indeed, the volume of research on characterization − and engineering − of PETase, a depolymerase specific to the common polyester poly­(ethylene terephthalate) (PET), highlights the potential of this enzyme to degrade PET on a large scale.…”

“…Immobilization of enzymes on solid surfaces has numerous advantages in industrial contexts, including reusability and enhanced catalytic stability. ,,,,− Strategies for preparation of immobilized enzymes (covalent tethering through both native and installed functional groups, carrier-free cross-linking, both specific and nonspecific adsorption, etc.) have been reviewed in-depth by several research groups. ,− Several published studies have explored PETase immobilization on metallic supports as a means of increasing stability by genetically fusing the enzyme to a metal-binding polyhistidine tag. , It has been shown that immobilization, even without introduction of spacer molecules to reduce steric hindrance, has the potential to enhance PETase activity and stability in harsh temperature and pH conditions , but the full scope of PETase immobilization has yet to be explored.…”

Surface Modification of Magnetic ZIF-90 Nanoparticles Improves the Microenvironment of Immobilized Lipase and Its Application in Esterification

“…MOFs have characteristics of a high specific surface area, high porosity, and easy functional modification. They have considerable application potential in gas adsorption, separation, energy storage, proton conduction, and drug transport. − Owing to the diversity of structures and types of metal nodes and organic ligands, researchers can flexibly design and synthesize MOFs with specific geometry, size, and function such that they can be used as excellent biomolecular immobilization platforms. , In general, enzymes are immobilized on MOFs mainly via three strategies: surface immobilization, encapsulation in the pores via diffusion, and coprecipitation . The nanometer size of the MOF–enzyme complex ensures that it has good dispersion, which makes it difficult to separate it from the reaction medium and reduces its reusability.…”

Structural Diversity and Carbon Dioxide Sorption Selectivity of Zinc(II) Metal-Organic Frameworks Based on Bis(1,2,4-triazol-1-yl)methane and Terephthalic Acid

“…Metal–organic frameworks (MOFs) are one of the most perspective classes of coordination polymers due to their luminescent and sensing properties [ 8 , 9 , 10 , 11 , 12 , 13 ], catalytic activity [ 14 , 15 , 16 , 17 ], and high sorption capacity or sorption selectivity toward gases [ 18 , 19 , 20 ] and liquids [ 21 , 22 ]. Emerging applications of MOFs include targeted drug delivery [ 23 , 24 ], enzyme immobilization [ 25 , 26 ] and bio-imaging [ 27 , 28 ]. The most widespread approach to build MOFs is to use a three-component system of metal ion, di- or polycarboxylate ligand and N,N-bitopic auxiliary ligand that self-assembles into a 3D porous coordination polymer [ 29 , 30 , 31 , 32 ].…”