Biocatalysis

Introduction

Biocatalysis, which can facilitate biotransformation catalyzed by biomacromolecules and even whole cells, is an indispensable part of catalysis industries. The biocatalysts, commonly referred as enzymes, can reduce the reaction activation energy with unparalleled efficiency, selectivity and specificity. Until now, over 5000 catalytic reactions in different industries benefit from the enzymes-based biocatalysis, which are highly reactive and environmentally friendly. Although enzymes possess unparallel advantages than other catalysts, their poor stability, low recyclability, and difficult recovery procedures in general impede their further utilization in catalysis industries. To circumvent the shortcomings in biocatalysis, a promising strategy has been proposed, namely enzyme immobilization into solid materials. Enzyme immobilization into solid supports not only improves convenient handling and rapid separation but also increases their stability against organic solvents or heat. The critical point about enzyme immobilization is the choice of solid support. MOFs and COFs have unparalleled advantages compared with other conventional solid supports materials such as silica, glass, graphene oxides, carbon nanotubes, polymer microcapsules, and hydrogel attributing to their unique characteristics.

Application of MOFs in Biocatalysis

The diversity of building units, molecular-scale tunability, and modular synthetic routes of MOFs greatly expand its ability as the host to integrate with biocatalysts. MOFs can be used as favourable solid supporting materials to immobilize various enzymes to enhance their catalytic activities^[1].

• Immobilization of natural enzymes: The stability of all kinds of natural enzymes in harsh conditions can be usually enhanced by MOFs. The natural enzymes include oxidoreductases (horse radish peroxidase, catalases, Cyt C, glucose oxidase and etc.), hydrolase (urease, β-glucosidase, RNase, protease and etc.), lyase (carbonic anhydrase and etc.), multienzymes and many others.
• Immobilization of metal-based artificial enzyme mimics: Apart from natural enzyme immobilization, alternatively, enzyme mimics such as metal nanoparticles are a promising strategy in biocatalysis, MOFs are regarded as one of the best supporting materials for nanozymes because of their large surface areas and highly tunable porous environments, thus avoiding the deactivation of enzymes mimics caused by nanoparticle aggregation during catalysis.
• Protection of whole organisms: Exclusive of natural and artificial enzymes, living organisms such as whole cells or viruses also play irreplaceable roles in biocatalysis or biotransformation. MOFs have recently emerged as alternative and attractive candidates for extracellular coatings provide a strong protection on organisms under hostile environments to preserve the biological functionalities of cells.

Furthermore, MOFs not only can be excellent supporting materials for enzyme immobilization, but also can be excellent enzyme mimics and stimuli-responsive biocatalysts by themselves, owing to their unique structural properties.

Application of COFs in Biocatalysis

Highly porous and diversity nature of COFs might consider as perfect host materials for enzyme immobilization to improve the desirable properties of enzymes for biocatalysts such as poor stability, low operational range, lack of repeatability, and products/by-products inhibition for large-scale applications. The enzymes can be immobilized into COFs through different techniques, the details are as follows^[2].

• Immobilization by physical adsorption: Physical adsorption is a straightforward and simple approach for the immobilization of enzymes into COFs carriers. Accomplished by different interactions, including ionic interactions, hydrogen bonding, and van der Waals forces, which permits the adsorptive attachment of a variety of enzymes in COFs materials.
• Immobilization by covalent attachment: That is, the direct covalent attachment between the enzyme molecules and COFs or through a cross-linking agent. The introduction of specific functional moieties, which facilitates the covalent linkage of the enzyme, can be strengthened the combination of the enzyme molecules and COFs, further, the improving the prospect of enzyme used in repeated cycles and reducing the enzyme leaching.

What Can Alfa Chemistry Do

Alfa Chemistry provides high-quality MOFs and COFs used in biocatalysis field for enzyme immobilization to improve enzyme catalytic activities. And our professional technology team that can also provide customers with high-quality MOFs and COFs design and customization services, no matter what design ideas you have, we will implement them together with you. In addition, Alfa Chemistry is committed to supporting customers a series of solutions in biocatalytic fields by using MOFs and COFs. Please contact us immediately to order or cooperate in research and development with high quality and reasonable price.