Enzyme Stabilization and Immobilization by Sol-Gel Entrapment (original) (raw)

Enzyme immobilization using two processing methods onto silica core-shell particles

Boletín de la Sociedad Española de Cerámica y Vidrio, 2020

b o l e t í n d e l a s o c i e d a d e s p a ñ o l a d e c e r á m i c a y v i d r i o x x x (2 0 2 0) xxx-xxx invertase immobilization at 40 • C. The immobilized invertase showed decreased activity, but it was not hampered by substrate inhibition, as in the case of the free enzyme, due to the location of the enzyme inside the mesoporous silica layer, where the mass transfer resistance for the substrate to the enzyme active site was present.

Enzyme Immobilization: The Quest for Optimum Performance

Advanced Synthesis & Catalysis, 2007

Immobilization is often the key to optimizing the operational performance of an enzyme in industrial processes, particularly for use in non-aqueous media. Different methods for the immobilization of enzymes are critically reviewed. The methods are divided into three main categories, viz. (i) binding to a prefabricated support (carrier), (ii) entrapment in organic or inorganic polymer matrices, and (iii) cross-linking of enzyme molecules. Emphasis is placed on relatively recent developments, such as the use of novel supports, e.g., mesoporous silicas, hydrogels, and smart polymers, novel entrapment methods and cross-linked enzyme aggregates (CLEAs).

Current Trend in Enzyme Immobilization: A Review

2013

The term "immobilized enzymes" refers to "enzymes physically confined or localized in a certain defined region of space with retention of their catalytic activities, and which can be used repeatedly and continuously". Besides the application in industrial processes, the immobilization techniques are the basis for making a number of biotechnological products with applications in diagnostics, antibiotic production, bioremediation and biosensors. The major components of an immobilized enzyme system are the enzyme, the matrix, and the mode of attachment. The enzymes can be attached to the support by interactions ranging from reversible physical adsorption and ionic linkages to stable covalent bonds. As a consequence of enzyme immobilization, some properties such as catalytic activity or thermal stability become altered. However, immobilized enzymes possess the capability of reuse, low cost of production and have many industrial and medical applications. The concept o...

Advantages of the Pre-Immobilization of Enzymes on Porous Supports for Their Entrapment in Sol−Gels

Biomacromolecules, 2005

In this work, we have compared the entrapment of free or previously immobilized glucose oxidase using a sol-gel technique. The preimmobilization was carried out on Sepabeads (a porous support) derivatized with glutaraldehyde as the functional group. The prior immobilization of the enzyme permitted to maintain the enzyme activity intact after the formation of the sol-gel. In fact, only 10% of the enzyme activity was lost whereas the soluble enzyme lost 60% of its initial activity. Additionally, enzyme leakage from the sol-gel matrix was avoided, which was relatively high when entrapping the soluble enzyme (39% of the enzyme activity was released after 16 h of incubation in a buffered solution). Moreover, the immobilized enzyme, inside the porous support, cannot be in contact with the sol-gel, and, therefore, it maintained the stability achieved by means of the multipoint covalent attachment on the Sepabeads support.

Stable Immobilization of Enzymes in a Macro- and Mesoporous Silica Monolith

ACS Omega, 2019

Horseradish peroxidase isoenzyme C (HRP) and Engyodontium album proteinase K (proK) were immobilized inside macro-and mesoporous silica monoliths. Stable immobilization was achieved through simple noncovalent adsorption of conjugates, which were prepared from a polycationic, water-soluble second generation dendronized polymer (denpol) and the enzymes. Conjugates prepared from three denpols with the same type of repeating unit (r.u.), but different average lengths were compared. It was shown that there is no obvious advantage of using denpols with very long chains. Excellent results were achieved with denpols having on average 750 or 1000 r.u. The enzyme-loaded monoliths were tested as flow reactors. Comparison was made with microscopy glass coverslips onto which the conjugates were immobilized and with glass micropipettes containing adsorbed conjugates. High enzyme loading was achieved using the monoliths. Monoliths containing immobilized denpol−HRP conjugates exhibited good operational stability at 25°C (for at least several hours), and good storage stability at 4°C (at least for weeks) was demonstrated. Such HRP-containing monoliths were applied as continuous flow reactors for the quantitative determination of hydrogen peroxide in aqueous solution between 1 μM (34 ng/mL) and 50 μM (1.7 μg/mL). Although many methods for immobilizing enzymes on silica surfaces exist, there are only a few approaches with porous silica materials for the development of flow reactors. The work presented is a promising contribution to this field of research toward bioanalytical and biosynthetic applications.

Biocatalysis by sol-gel entrapped enzymes

Journal of Non-Crystalline Solids, 1992

Attachment of enzymes to insoluble matrix is an essential step in the development of biocatalysts. Transparent xerogels containing various enzymes were obtained by mixing a solution of an enzyme with tetra-methoxy orthosilicate (TMOS) at room temperature followed by gelation and drying. Effective immobilization was usually obtained at initial pH values > 7, where there is a change in the gelation mechanism from predominant hydrolysis/condensation to predominant direct polymerization of silicate precursors. The properties of sol-gel matrix, namely, transparency, large hydrophilic surface and good chemical and thermal stability, make it an ideal material for both biocatalysts and optical sensor devices. An example of a simple optical glucose sensor is demonstrated.

An Overview of Enzyme Immobilization

2017

The use of enzymes as biological catalysts has gained increasing importance in industries. Although enzymes can be obtained from plant and animal origin, microbial enzymes have several advantages over enzymes derived from other sources. Due to the high cost of separation of enzymes from product, the instability of enzymes and reduced enzyme activity, several strategies are now been explored to develop immobilized enzymes. Immobilized enzymes have been produced by cell immobilization techniques. Immobilized enzymes have found several industrial applications where they provide the advantages of easy separation of the enzyme from the product, reuse of the enzyme, convenient handling, high stability under extreme physical and chemical conditions, being applicable for all types of reactors with varied interior design, and provides easier process control. However, despite these advantages, enzyme immobilization techniques continue to pose some challenges. These challenges notwithstanding,...

Enzyme immobilization in biotechnology

Recent Patents on Engineering, 2008

Enzymes are proteins that catalyze chemical reactions. Unlike more traditional organic and inorganic catalysts, enzymes are large and fragile molecules, so over the years, scientists and engineers have found it more difficult to immobilize enzyme catalysts on easily separateable supports for use and re-use in a variety of technologies. Over the last decade, enzyme immobilization has become more important in industry, medicine, and biotechnology. This review will detail recent patents for techniques for enzyme immobilization, along with patents for chemical and biotechnological processes that can employ immobilized enzymes, which allow for the re-use of the enzymatic catalysts. These techniques include methods varying from physical adsorption and covalent attachment to entrapment in polymers and sol-gels. These techniques have shown value in the development of biosensors, bioprocessing for the chemical industry and the pharmaceutical industry, and bioremediation.