Immobilization of enzymes on alginic acid-polyacrylamide copolymers (original) (raw)
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Enzyme immobilization on graft copolymers
1999
Immobilised enzymes can be reused, easily separated from the reaction medium, and are more stable in most of the cases. Despite of these advantages, there are still some problems facing the usage of the immobilised enzyme in industry. One of those problems is diffusion-limitation of both the reactants and the products. This problem becomes even more serious when the products are inhibitors of the enzymes. Different strategies for overcoming this problem have been discussed in this thesis. A new solution to overcome diffusion limitation is based on processing the enzymatic reaction under non-isothermal conditions. In such a bioreactor the enzymes have to be immobilised on a hydrophobic membrane. In this thesis, two enzymes,β-galactosidase and penicillin G acylase have been immobilised onto teflon and nylon membranes. Two grafting techniques have been used to modify the membranes in order to be able to bind the enzyme. These grafting techniques were based on using high-energy radiatio...
Polymer-Based Strategies for Enzyme Immobilization: A Comprehensive Review
Tuijin Jishu/Journal of Propulsion Technology, 2023
Enzyme immobilization refers to the process of attaching or confining enzymes onto a solid support or within a matrix, often made of polymers or other materials. This immobilization creates a stable and controlled environment for the enzyme to interact with substrates and perform catalysis. The primary goal of enzyme immobilization is to enhance enzyme stability, reusability, and activity under specific conditions, making them more practical and efficient for various biotechnological, industrial, and medical applications. Immobilization methods can vary widely, including physical adsorption, covalent bonding, entrapment within matrices, encapsulation, crosslinking, and more. These methods provide a means to control the interactions between the enzyme and the surrounding environment, affecting factors such as substrate accessibility, enzyme orientation, and stability. Due to their ease of fabrication and superior structural adaptability, polymer compounds in a variety of physical forms, including beads, films, fibers,and coatings,have become popular as supportive materials for enzyme immobilization. For enzyme immobilization, a number of natural polymers, including agar, agarose, alginate, dextran, chitosan,and carrageenan, as well as synthetic polymers, such as polyamides, polystyrene, and polyacrylamide, are often employed as a carrier system. The immobilization offers a cost-effective system for various applications in biotechnology, industry, and research.
Biotechnology and Bioengineering, 1980
A method.of enzyme immobilization by graft copolymerization on polysaccharides is reported. Glycidylmethacrylate was used as a vinylating reagent and the reaction product with enzymes (HRP, GOD, Am, ChT) was copolymerized with different matrices (cellulose, Sepharose, Sephadex, starch). Various factors affect the final activity of copolymers; these include the redox system, the type of support, and the quantity and type of vinyl monomer added. Using a fixed quantity of enzyme and support (3 mg enzyme, 100 mg support), the coupling efficiency varied from 2 to 50%. The most important characteristics in these immobilized systems were tested (stability in continuous washing, kinetic characteristics, storage, thermal, and lyophilization stability). Immobilized-enzyme graft copolymers have very similar kinetic behavior to that of the free enzyme. Diffusion is not seriously limited, as shown by kinetic parameters and energy activation values, and this indicates that the immobilization reaction does not alter the enzymatic activity.
Immobilization of Enzymes by Polymeric Materials
Catalysts
Enzymes are the highly efficient biocatalyst in modern biotechnological industries. Due to the fragile property exposed to the external stimulus, the application of enzymes is highly limited. The immobilized enzyme by polymer has become a research hotspot to empower enzymes with more extraordinary properties and broader usage. Compared with free enzyme, polymer immobilized enzymes improve thermal and operational stability in harsh environments, such as extreme pH, temperature and concentration. Furthermore, good reusability is also highly expected. The first part of this study reviews the three primary immobilization methods: physical adsorption, covalent binding and entrapment, with their advantages and drawbacks. The second part of this paper includes some polymer applications and their derivatives in the immobilization of enzymes.
Natural polymers: suitable carriers for enzyme immobilization
2021
Enzyme immobilization onto support carriers has the potential to overcome some of the limitations of soluble enzymes in practical applications. Various materials have been used as carriers, such as inorganic matrices, as well as natural and synthetic polymers. Production of carriers from natural biopolymers and their derivatives has been the focus of research worldwide, and a summary of their applications for enzyme immobilization is presented in this paper. Enzymes, or cells as an enzyme source, are entrapped inside a three-dimensional polymeric network, called a hydrogel, that is able to retain large amounts of water. This network can be formed by chemical cross-linking, ionotropic gelling in the presence of cation, or in thermo reverse polymerization, depending on the polymer in use and its physico-chemical characteristics. The most frequently used biopolymers as carriers for immobilization include alginate, cellulose, chitosan, collagen, xylan, pectin, and others.
New supports for enzyme immobilization based on copolymers of vinylene carbonate and acrylamide
Applied Biochemistry and Biotechnology, 2001
Vinylene carbonate (VCA), -hydroxyethylene acrylate, and N,NЈ-methylene bisacrylamide were dissolved in water, and the aqueous solutions were copolymerized via reverse-phase suspension copolymerization in paraffin oil. A series of hydrophilic and beaded supports containing reactive cyclic carbonate groups for enzyme immobilization were obtained. The supports were examined by coupling with trypsin, and the results showed that the amount of enzymes coupled to the supports and the specific activity of the immobilized trypsin were related to the content of VCA structure units and the reaction time. Meanwhile, the optimal pH and temperature, as well as the Michaelis-Menten constant K m , for both native and immobilized trypsin were measured.
Lactam-amide graft copolymers as novel support for enzyme immobilization
Journal of Applied Polymer Science, 2002
A graft random copolymer of N-vinyl-2-pyrrolidone and N,NЈ-dimethylacrylamide onto polypropylene was synthesized using a simultaneous gamma radiation technique from a 60 Co source, so that the hydrogel poly(propylene-g-vinylpyrrolidoneco-N,NЈ-dimethylacrylamide) [PP-g-(VP-co-DMAM)], thus produced by grafting, could be used as a support for enzyme immobilization. The grafted spheres showed very good swelling behavior in water due to the incorporation of hydrophilicity in the PP spheres. The influence of pH and temperature on as well as the determination of the kinetic parameters, K M and V max , for both immobilized and soluble invertase were determined. PP-g-(VP-co-DMAM) grafting onto the PP spheres caused a significant change in the water content of the support and was more pronounced for the spheres with a high degree of grafting. A porous structure of the polymeric spheres was observed by scanning electron microscopy (SEM). The porous structure contributed to the reaction rate decrease due to diffusional effects, as shown by the larger K M value observed for immobilized invertase relative to the free enzyme. The enzyme affinity for the substrate (K M /V max) remains quite good after immobilization. The thermal stability of immobilized invertase was significatively higher than that of the free enzyme and a displacement of 20°C was observed for the immobilized enzyme.
Poly(EGDMA/AAm) copolymer beads: a novel carrier for enzyme immobilization
Reactive and Functional Polymers, 1998
In this study, we evaluated a new carrier (i.e., the poly(EGDMA /AAm copolymer beads) for enzyme immobilization. Two different types of copolymer beads with different swellabilities with an average diameter of about 200 mm were produced by suspension copolymerization of the respective comonomers, with or without using toluene. BPO and PVA were used as the initiator and the stabilizer. The copolymer beads produced without toluene were nonporous and nonswellable. While porous and swellable (swelling ratio: 14.28%) beads were obtained in which toluene was used as the diluent. Both type of beads were modified by using glutaraldehyde and hexamethylene diamine as the coupling agent and the spacer-arm, respectively. Immobilization of a model enzyme (i.e., glucose oxidase) was studied to show the feasibility of using these beads as an enzyme carrier. More enzyme, but with very low activities, were immobilized on the beads with relatively lower swellabilities. While much higher activities were observed on the beads with relatively higher swellabilities prepared with toluene. Incorporation of the spacer-arm (i.e., hexamethylene diamine) increased the apparent activity of the immobilized enzyme. The optimal glutaraldehyde concentrations to achieve the highest immobilized enzyme activities for the swellable and nonswellable beads were 23.1 and 4.8% (v / v), respectively, while the optimal hexamethylene diamine concentrations to achieve the highest immobilized enzyme activities for these beads were 0.10 and 0.16 mmol / ml, respectively.
Enzyme immobilization onto renewable polymeric matrixes: Past, present, and future trends
Journal of Applied Polymer Science, 2015
ABSTRACTIn this review, we present an overview of the different renewable polymers that are currently being used as matrixes for enzyme immobilization and their properties and of new developments in biocatalysts preparation and applications. Polymers obtained from renewable resources have attracted much attention in recent years because they are environmentally friendly and available in large quantities from natural sources. Different methods for the immobilization of enzymes with these matrixes are reviewed, in particular: (1) binding to a prefabricated biopolymer, (2) entrapment, and (3) crosslinking of enzyme molecules. Emphasis is given to relatively recent developments, such as the use of novel supports, novel entrapment methods and protocols of polymer derivatization, and the crosslinking of enzymes. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42125.
Enzyme immobilization by poly(vinyl alcohol) gel entrapment
Journal of Molecular Catalysis, 1982
A method is presented the formation of poly(vinyI for gel entrapment of enzymes [II, consisting of alcohol) fdrn from enzyme-containing poiy(vinyl alcohol) solution by drying or salt treatment_ The yield of immobilization can be enhanced by adding materials protecting the enzymes (inert proteins, -SH-compounds, etc_) to the gel-forming solution to decrease enzyme leakage. The details of immobilization procedure and some properties of aldolase arrd neutral lactase immobilized in this manner are described.