Pore Environment Control and Enhanced Performance of Enzymes Infiltrated in Covalent Organic Frameworks

Abstract

In the drive toward green and sustainable methodologies for chemicals manufacturing, biocatalysts are predicted to have much to offer in the years to come. That being said, their practical applications are often hampered by a lack of long-term operational stability, limited operating range, and a low recyclability for the enzymes utilized. Herein, we show how covalent organic frameworks (COFs) possess all the necessary requirements needed to serve as ideal host materials for enzymes. The resultant biocomposites of this study have shown the ability boost the stability and robustness of the enzyme in question, namely lipase PS, while also displaying activities far outperforming the free enzyme and biocomposites made from other types of porous materials, such as mesoporous silica and metal-organic frameworks, exemplified in the kinetic resolution of the alcohol assays performed. The ability to easily tune the pore environment of a COF using monomers bearing specific functional groups can improve its compatibility with a given enzyme. As a result, the orientation of the enzyme active site can be modulated through designed interactions between both components, thus improving the enzymatic activity of the biocomposites. Moreover, in comparison with their amorphous analogues, the well-defined COF pore channels not only make the accommodated enzymes more accessible to the reagents but also serve as stronger shields to safeguard the enzymes from deactivation, as evidenced by superior activities and tolerance to harsh environments. The amenability of COFs, along with our increasing understanding of the design rules for stabilizing enzymes in an accessible fashion, gives great promise for providing "off the shelf" biocatalysts for synthetic transformations.

Defective 2D Covalent Organic Frameworks for Postfunctionalization

“…Covalent organic frameworks (COFs), which are constructed by light elements (B, O, N, and C) and connected by covalent bonds, are a class of crystalline polymers and have developed rapidly in the last decade. Their tunable structures and pore sizes, high surface area values, and good thermal/chemical stabilities make them good candidates in various applications . Since the first COF was reported by Yaghi's group in 2005, numerous 2D or 3D COFs have been achieved by utilizing different kinds of building blocks via dynamic covalent chemistry principle.…”

Covalent Organic Frameworks: Chemical Approaches to Designer Structures and Built‐In Functions

“…This enhanced activity originates from the binding of the enzyme to TPB‐DMTP‐COF so that a conformational change occurs to offer easy access to the catalytic site. Interestingly, the composite is stable at high temperatures, such as 120 °C, and exhibits excellent recyclability and good applicability of other alcohols . Perylene CTF (Figure j) films loaded with a rhodium complex can be coupled with NADH/formate dehydrogenase to form a binary photocatalyst/biocatalyst system that harvests visible light to produce HCOOH from CO 2 at a rate of 881×10 6 nmol g −1 h −1 with high stability and reusability …”

Kovalente organische Gerüstverbindungen: chemische Ansätze für Designerstrukturen und integrierte Funktionen

“…B. 120 °C, stabil, sehr gut wiederverwendbar und gut für andere Alkohole anwendbar . Mit einem Rhodiumkomplex beladene Perylen‐CTF‐Filme (Abbildung j) werden mit NADH/Formiat‐Dehydrogenase zu einem binären Photokatalysator/Biokatalysator‐System gekuppelt, das sichtbares Licht sammelt, um mit einer Rate von 881×10 6 nmol g −1 h −1 mit hoher Stabilität und Wiederverwendbarkeit HCOOH aus CO 2 zu erzeugen …”

“…120 8 8C, stabil, sehr gut wiederverwendbar und gut für andere Alkohole anwendbar. [220] Mit einem Rhodiumkomplex beladene Perylen-CTF-Filme (Abbildung 49 j) werden mit NADH/Formiat-Dehydrogenase zu einem binären Photokatalysator/Biokatalysator-System gekuppelt, das sichtbares Licht sammelt, um mit einer Rate von 881 10 6 nmol g À1 h À1 mit hoher Stabilitätu nd Wiederverwendbarkeit HCOOH aus CO 2 zu erzeugen. [221] Wieo ben beschrieben, zeigen COFs ein enormes Potenzial fürd ie heterogene Katalyse.E sb leibt aber die grundsätzliche Frage zu klären, wie die porçsen Gerüste ihre besonderen Eigenschaften in der Katalyse manifestieren kçnnen.…”