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Questions and Answers
Which immobilization method is known for its high cost?
Which immobilization method is known for its high cost?
What is a significant disadvantage of cross linking in enzyme immobilization?
What is a significant disadvantage of cross linking in enzyme immobilization?
Which immobilization method has the strongest binding force?
Which immobilization method has the strongest binding force?
In which immobilization method is enzyme leakage most likely to occur?
In which immobilization method is enzyme leakage most likely to occur?
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Which of the following are associated with the limitations of enzyme immobilization?
Which of the following are associated with the limitations of enzyme immobilization?
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Which immobilization method has been described as having a wide applicability?
Which immobilization method has been described as having a wide applicability?
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What common problem is noted across most enzyme immobilization techniques?
What common problem is noted across most enzyme immobilization techniques?
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Which of the following statements is true regarding entrapped enzymes?
Which of the following statements is true regarding entrapped enzymes?
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What is a disadvantage of using entrapment for enzyme immobilization?
What is a disadvantage of using entrapment for enzyme immobilization?
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Which of the following is a characteristic of lattice-type entrapment?
Which of the following is a characteristic of lattice-type entrapment?
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What is a disadvantage of covalent binding in enzyme immobilization?
What is a disadvantage of covalent binding in enzyme immobilization?
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Which type of entrapment allows for the retention of protein while permitting substrate penetration?
Which type of entrapment allows for the retention of protein while permitting substrate penetration?
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What is a key advantage of cross-linking enzymes in the immobilization process?
What is a key advantage of cross-linking enzymes in the immobilization process?
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Which of the following polymers can be used in lattice-type entrapment?
Which of the following polymers can be used in lattice-type entrapment?
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What is a primary characteristic of microcapsule entrapment?
What is a primary characteristic of microcapsule entrapment?
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What is a key advantage of using entrapment for enzyme immobilization?
What is a key advantage of using entrapment for enzyme immobilization?
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What is enzyme immobilization primarily aimed at achieving?
What is enzyme immobilization primarily aimed at achieving?
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Which of the following is NOT one of the advantages of immobilizing enzymes?
Which of the following is NOT one of the advantages of immobilizing enzymes?
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Which type of carriers is characterized by being cost-effective and stable?
Which type of carriers is characterized by being cost-effective and stable?
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What type of interaction is involved in the adsorption method of enzyme immobilization?
What type of interaction is involved in the adsorption method of enzyme immobilization?
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Which of the following is an example of an inorganic carrier for enzyme immobilization?
Which of the following is an example of an inorganic carrier for enzyme immobilization?
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Which of the following methods for enzyme immobilization is categorized as a chemical method?
Which of the following methods for enzyme immobilization is categorized as a chemical method?
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What is a characteristic of an ideal carrier matrix for enzyme immobilization that aids in reducing product inhibition?
What is a characteristic of an ideal carrier matrix for enzyme immobilization that aids in reducing product inhibition?
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Which of the following statements about entrapment as a physical method of enzyme immobilization is true?
Which of the following statements about entrapment as a physical method of enzyme immobilization is true?
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Study Notes
Enzyme Immobilization
- Enzyme immobilization is a process of confining enzyme molecules to a solid support. A substrate is passed over the support, and converted to products.
- An immobilized enzyme is one whose movement in space is restricted, either completely or to a small, limited region.
Why Immobilize Enzymes?
- Protection from degradation and deactivation
- Re-use for many reaction cycles, reducing enzyme costs
- Ability to stop reactions quickly by removing the enzyme
- Enhanced stability
- Easy enzyme product separation
- Product purity, no enzyme contamination
Ideal Carrier Matrices for Enzyme Immobilization
- Inert
- Physically strong and stable
- Cost effective
- Regenerable
- Reduces product inhibition
Classification of Carriers
-
Inorganic Carriers:
- High pressure stability
- May undergo abrasion
- Examples: commercially available SiO2 materials (porous glass, silica), mineral materials (clays, like Celite, and bentonite)
-
Organic Natural Carriers:
- Favorable compatibility with proteins
- Examples: cellulose derivatives (ODEAE-cellulose, OCM- cellulose), dextran, polysaccharides (agarose, starch, pectine, chitosan)
-
Organic Synthetic Carriers:
- High chemical and mechanical stability
- Examples: polystyrene, polyvinylacetate, acrylic polymers
Methods for Enzyme Immobilization
-
Physical Methods:
- Adsorption
- Entrapment
- Encapsulation
-
Chemical Methods:
- Covalent Binding
- Cross-linking
Physical Methods: Adsorption
- Physical binding of the enzyme to the surface of an organic or inorganic carrier matrix.
- Weak interactions (Vander Waals or hydrogen bonds) hold the enzyme.
- Examples of carriers: silica, bentonite, cellulose
- Examples of enzymes: catalase, invertase
Physical Methods: Entrapment
- Enzymes are trapped within suitable gels or fibers.
- Retains the protein while allowing substrate penetration.
- Two types: lattice and microcapsule
- Lattice Example: polyacrylamide gel, polyvinyl alcohol gels, cellulose and polyacrylamide gels
- Microcapsule Example: polyamine, polybasic acid chloride monomers
Physical Methods: Encapsulation
- Enzymes are enclosed within semi-permeable polymer membranes.
- Examples: semi-permeable collodion or nylon membranes in spherical shapes
Advantages of Adsorption
- Simple and economical
- Limited activity loss
- Recyclable, regenerated
Disadvantages of Adsorption
- Relatively low surface area for binding
- Enzyme exposure to microbial attack
- Low yield due to inactivation (and desorption)
Advantages of Entrapment
- No chemical modification
- Relatively stable forms
- Easy handling and re-usage
Disadvantages of Entrapment
- Enzyme leakage from the pores
Chemical Methods: Covalent Binding
- Enzymes are bound to water-insoluble carriers by covalent bonds.
- Functional groups (Amino, Carboxyl, Sulfhydryl, Hydroxyl, Imidazole, Phenolic, Thiol) involved in the binding.
- May alter enzyme conformation, resulting in activity and/or substrate changes.
- High binding strength: prevents leakage even in high ionic substrate solutions
Chemical Methods: Cross-Linking
- Intermolecular cross-linking of enzyme molecules to create 3-dimensional insoluble aggregates often in the absence/presence of solid support.
- Multifunctional reagents covalently link enzyme molecules.
- Highly stable enzyme-bound reactions- little desorption
Advantages of Cross-Linking
- Very little desorption
- Higher stability (pH, ionic, and substrate concentrations)
Disadvantages of Cross-Linking
- Cross-linking significantly alters the active site
- Not cost-effective
Comparison of Immobilization Methods
Comparison table given (Page 17). See the document for the table.
Limitations of Enzyme Immobilization
- High cost of carriers and immobilization
- Changes in enzyme properties (selectivity)
- Mass transfer limitations
- Problems with cofactor regeneration
- Problems with multienzyme systems
- Activity loss during immobilization
Conclusion
- Enzyme immobilization is a promising technique for biotransformation, diagnostics, and food/pharmaceutical industries.
- Many enzymes like penicillin G acylase, lipases, proteases, invertase are used.
- Current limitations in immobilization techniques need to be overcome to expand its applications.
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Description
Explore the fundamental concepts of enzyme immobilization, including its benefits, ideal carrier matrices, and classification of carriers. This quiz delves into the mechanisms that enhance enzyme stability and functionality in various applications.
