Showing papers on "Immobilized enzyme published in 2022"

Applications of immobilized lipases in enzymatic reactors: A review

Abstract: Lipases are efficient biocatalysts with numerous applications in different industrial sectors, such as pharmaceutical, food, and fine chemistry industries. Enzyme immobilization further extends the applications of lipases by enhancing stability, selectivity, and half-life. However, obtaining high catalytic efficiency in reactions catalyzed by immobilized lipases requires optimization of reaction conditions (presence or absence of organic solvents, temperature, medium viscosity) and operational characteristics. This is a technical review focused on exploring the state-of-the-art of industrial applications of immobilized lipases in different reactor systems. Articles published between 2015 and 2020 were selected and analyzed to identify the major factors affecting the application of immobilized lipases, such as types of enzyme support, enzyme–support interactions (immobilization methods), substrate characteristics, and reactor configurations. The most common reactor configurations are discussed, as well as their advantages and disadvantages. In the current literature, studies on immobilized lipases and enzymatic reactors focus on developing strategies to minimize mass transfer limitations and eliminate the need for organic solvents.

Metal Nanoparticles@Covalent Organic Framework@Enzymes: A Universal Platform for Fabricating a Metal-Enzyme Integrated Nanocatalyst.

Abstract: Cascade catalysis that combines chemical catalysis and biocatalysis has received extensive attention in recent years, especially the integration of metal nanoparticles (MNPs) with enzymes. However, the compatibility between MNPs and enzymes, and the stability of the integrated nanocatalyst should be improved to promote the application. Therefore, in this study, we proposed a strategy to space-separately co-immobilize MNPs and enzymes to the pores and surface of a highly stable covalent organic framework (COF), respectively. Typically, Pd NPs that were prepared by in situ reduction with triazinyl as the nucleation site were distributed in COF (Tz-Da), and organophosphorus hydrolase (OPH) was immobilized on the surface of Tz-Da by a covalent method to improve its stability. The obtained integrated nanocatalyst Pd@Tz-Da@OPH showed high catalytic efficiency and reusability in the cascade degradation of organophosphate nerve agents. Furthermore, the versatility of the preparation strategy of COF-based integrated nanocatalyst has been preliminarily expanded: (1) Pd NPs and OPH were immobilized in the triazinyl COF (TTB-DHBD) with different pore sizes for cascade degradation of organophosphate nerve agent and the particle size of MNPs can be regulated. (2) Pt NPs and glucose oxidase were immobilized in COF (Tz-Da) to obtain an integrated nanocatalyst for efficient colorimetric detection of phenol.

Enzyme Immobilization and Co-Immobilization: Main Framework, Advances and Some Applications

Abstract: Enzymes are outstanding (bio)catalysts, not solely on account of their ability to increase reaction rates by up to several orders of magnitude but also for the high degree of substrate specificity, regiospecificity and stereospecificity. The use and development of enzymes as robust biocatalysts is one of the main challenges in biotechnology. However, despite the high specificities and turnover of enzymes, there are also drawbacks. At the industrial level, these drawbacks are typically overcome by resorting to immobilized enzymes to enhance stability. Immobilization of biocatalysts allows their reuse, increases stability, facilitates process control, eases product recovery, and enhances product yield and quality. This is especially important for expensive enzymes, for those obtained in low fermentation yield and with relatively low activity. This review provides an integrated perspective on (multi)enzyme immobilization that abridges a critical evaluation of immobilization methods and carriers, biocatalyst metrics, impact of key carrier features on biocatalyst performance, trends towards miniaturization and detailed illustrative examples that are representative of biocatalytic applications promoting sustainability.

Food enzymes immobilization: novel carriers, techniques and applications

Abstract: Food enzyme immobilization is a technology to mitigate various limitations of free enzymes in food processing. Versatile carriers such as agro-waste based materials, nano materials, and metal organic frameworks are developed to immobilize enzymes with improved enzymological characteristics to enable catalytic reactions to be carried out under sophisticated and extreme processing conditions. New fabrication technologies of immobilized food enzymes, for example, 3D printing and coaxial electrospraying also enhance enzyme functionality. Recent research on food enzyme immobilization is aimed at sustainability, cost-effectiveness, automation, high-throughput, multifunction, and safety. These developments enable new applications in food bioprocessing, food analyses, food control and food packaging, and so on.

MOF‐Hosted Enzymes for Continuous Flow Catalysis in Aqueous and Organic Solvents

Abstract: Abstract Fully exploiting the potential of enzymes in cell‐free biocatalysis requires stabilization of the catalytically active proteins and their integration into efficient reactor systems. Although in recent years initial steps towards the immobilization of such biomolecules in metal–organic frameworks (MOFs) have been taken, these demonstrations have been limited to batch experiments and to aqueous conditions. Here we demonstrate a MOF‐based continuous flow enzyme reactor system, with high productivity and stability, which is also suitable for organic solvents. Under aqueous conditions, the stability of the enzyme was increased 30‐fold, and the space–time yield exceeded that obtained with other enzyme immobilization strategies by an order of magnitude. Importantly, the infiltration of the proteins into the MOF did not require additional functionalization, thus allowing for time‐ and cost‐efficient fabrication of the biocatalysts using label‐free enzymes.

Enzyme Immobilization Strategies for the design of robust and efficient biocatalysts

Abstract: Different strategies for the preparation of efficient and robust immobilized biocatalysts are here reviewed. Different physico-chemical approaches are discussed. i.- The stabilization of enzyme by any kind of immobilization on pre-existing porous supports. ii.- The stabilization of enzymes by multipoint covalent attachment on support surfaces. iii.- Additional stabilization of immobilized-stabilized enzyme by physical or chemical modification with polymers. These three strategies can be easily developed when enzymes are immobilized in pre-existing porous supports. In addition to that, these immobilized-stabilized derivatives are optimal to develop enzyme reaction engineering and reactor engineering. Stabilizations ranging between 1000 and 100,000 folds regarding diluted soluble enzymes are here reported.

Emerging 3D Printing Strategies for Enzyme Immobilization: Materials, Methods, and Applications

Abstract: As the strategies of enzyme immobilization possess attractive advantages that contribute to realizing recovery or reuse of enzymes and improving their stability, they have become one of the most desirable techniques in industrial catalysis, biosensing, and biomedicine. Among them, 3D printing is the emerging and most potential enzyme immobilization strategy. The main advantages of 3D printing strategies for enzyme immobilization are that they can directly produce complex channel structures at low cost, and the printed scaffolds with immobilized enzymes can be completely modified just by changing the original design graphics. In this review, a comprehensive set of developments in the fields of 3D printing techniques, materials, and strategies for enzyme immobilization and the potential applications in industry and biomedicine are summarized. In addition, we put forward some challenges and possible solutions for the development of this field and some possible development directions in the future.

Template-Free In Situ Encapsulation of Enzymes in Hollow Covalent Organic Framework Capsules for the Electrochemical Analysis of Biomarkers.

Abstract: Although capsule-like materials as host carriers for enzyme encapsulation have been a hot topic in recent years, creating an ideal microenvironment for enhanced enzymatic performance is still a formidable challenge. Herein, we created a template-free method to in situ encapsulate natural enzymes in hollow covalent organic framework (COF) capsules at room temperature. The COF crystallites migrated from the inner core and self-assembled at the outside walls during the inside-out Ostwald ripening process, retaining the enzymes in the cavity. The adjustable hollow structure of the enzyme@COF capsule allowed the basic vibration of the enzyme to maintain a certain degree of freedom, thus significantly enhancing the enzymatic bioactivity. The hollow enzyme@COF capsule has large mesoporous tunnels allowing the efficient transport. In addition, the enzyme encapsulated in the capsule showed superior activity and ultrahigh stability under various extreme conditions that may lead to enzyme inactivation, such as high temperature, organic solvents, chelates, and the denaturing agent. Finally, the prepared hollow GOx@COF capsule was used for electrochemical sensing of glucose in human serum, and the electrochemical sensor exhibited high selectivity and satisfactory test results. This research not only provides a new way for COFs to encapsulate enzymes but also has potential applications in biocatalysis and biosensing, making artificial organelles possible.

Food enzymes immobilization: novel carriers, techniques and applications

Abstract: Food enzyme immobilization is a technology to mitigate various limitations of free enzymes in food processing. Versatile carriers such as agro-waste based materials, nano materials, and metal organic frameworks are developed to immobilize enzymes with improved enzymological characteristics to enable catalytic reactions to be carried out under sophisticated and extreme processing conditions. New fabrication technologies of immobilized food enzymes, for example, 3D printing and coaxial electrospraying also enhance enzyme functionality. Recent research on food enzyme immobilization is aimed at sustainability, cost-effectiveness, automation, high-throughput, multifunction, and safety. These developments enable new applications in food bioprocessing, food analyses, food control and food packaging, and so on.

Green and Scalable Fabrication of High-Performance Biocatalysts Using Covalent Organic Frameworks as Enzyme Carriers.

Abstract: Enzyme immobilization is essential to the commercial viability of various critical large-scale biocatalytic processes. However, vast challenges remain for the immobilization systems, such as difficulties in loading large enzymes, enzyme leaching, and limitations for large-scale fabrication. Herein, we describe a green and scalable strategy to prepare high-performance biocatalysts through in situ assembly of enzymes with covalent organic frameworks (COFs) under ambient conditions (aqueous solution and room temperature). The obtained biocatalysts possess exceptional reusability and stability and serve as efficient biocatalysts for important industrial reactions that cannot be efficiently catalyzed by free enzymes or traditional enzyme immobilization systems. Notably, this versatile enzyme immobilization platform is applicable to various COFs and enzymes. The reactions in an aqueous solution occurred within a short timeframe (ca. 10-30 min) and could be scaled up readily (ca. 2.3 g per reaction).

Nanoflowers: A New Approach of Enzyme Immobilization

Abstract: Enzymes are biocatalysts known for versatility, selectivity, and brand operating conditions compared to chemical catalysts. However, there are limitations to their large‐scale application, such as the high costs of enzymes and their low stability under extreme reaction conditions. Immobilization techniques can efficiently solve these problems; nevertheless, most current methods lead to a significant loss of enzymatic activity and require several steps of activation and functionalization of the supports. In this context, a new form of immobilization has been studied: forming organic‐inorganic hybrids between metal phosphates as inorganic parts and enzymes as organic parts. Compared to traditional immobilization methods, the advantages of these nanomaterials are high surface area, simplicity of synthesis, high stability, and catalytic activity. The current study presents an overview of organic‐inorganic hybrid nanoflowers and their applications in enzymatic catalysis.