Enzyme immobilization involves attaching enzymes to solid carriers or supports. This allows enzymes to be reused, protects them from degradation, and enables stopping reactions quickly. There are five main immobilization methods: adsorption, entrapment, encapsulation, covalent bonding, and cross-linking. Immobilization has various applications in industry like production of food, biofuels, and detergents. However, it also has limitations like loss of enzyme activity and problems with regeneration. Overall, immobilization is a promising approach for exploiting enzymes in biotechnology but further research is needed to address its current limitations.
2. Contents
• Introduction
• Need of enzyme immobilization
• Methods of enzyme immobilization
• Applications
• Limitations
• Conclusion
• References
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3. Introduction
• Enzymes are immobilized to allow the exchange of medium
containing substrate or effectors molecules.
• The process of confining the enzyme to the solid support or
carrier over which substrate is passed and converted to product.
Carrier
• The substances that are employed for the enzyme
immobilization.
• They are regenerable, stable and cost effective.
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4. Need of enzyme immobilization
• Protection from degradation and deactivation
• Retention of enzyme or enzyme free product
• Reuse of enzyme
• Cost efficiency
• Enhanced stability
• Ability to stop the reaction rapidly by removing enzyme from
the reaction solution
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5. Methods of Enzyme Immobilization
Based on the support or matrix and type of bond involved , there
are five types of methods involved in enzyme immobilization.
1. Adsorption
2. Entrapment
3. Encapsulation
4. Covalent bonding
5. Cross linking
Fig No. 1: An overview of methods of enzyme immobilization
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6. Adsorption
• In this method the physical binding of the enzyme on the surface
of carrier matrix
• The enzyme is absorbed to the external surface of the carrier by
the weak interaction like Vander Waal or hydrogen bonds
• Nelson and Griffin used charcoal to absorb invertase
• Support/ carrier may be
1. Mineral support (Aluminum oxide, clay)
2. Organic support (Starch)
3. Modified sapharose and ion exchange resins.
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7. Entrapment
• In entrapment, the enzymes are not directly attached to the
support or carrier, but simply entrapped inside the polymer
matrix
• Enzymes are held or entrapped within suitable gels or fibers
• It can be classified into
1. Inclusion in gels: Polyacrylamide gel, poly vinyl alcohol gel
2. Inclusion in fibers: Cellulose
3. Inclusion in microcapsule: Polyamine,
Calcium alginate
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8. Encapsulation
• Immobilization is done by enclosing the enzyme semi-
permeable membrane like nitro cellulose or nylon
• In this method the effectiveness is depend on the stability of the
enzymes inside the membrane
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9. Covalent bonding
• This method involve formation of covalent bond between
chemical group in enzyme and chemical group on support/
carrier.
• It is one of the widely used method of enzyme immobilization.
• Hydroxyl and amino group of enzyme or carrier form covalent
bond more easily.
Carrier mainly used
1. Carbohydrate : cellulose, agarose
2. Protein: collagen, gelatin
3. Synthetic agents: polyacrylamide
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10. 4. Amino group bearing: amino benzyl cellulose
5. Inorganic carrier: porous glass, silica
Cross Linking
• This method is also called as copolymerization
• In this method enzymes directly linked by covalent bond
between various group of enzyme via polyfunctional group
• Unlike to other methods, there is no matrix or support involved
in this method
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11. Application
• Industrial production
• Biomedical application
• Food industry
• Research
• Production of bio-diesel
• Waste water management
• Textile industry
• Detergent industry
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12. Limitation
• Cost of carrier and immobilization
• Changes in properties
• Problem with regeneration
• Problem with multienzymes system
• Activity loss during immobilization
• Mass transfer limitation
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13. Conclusion
• Enzyme immobilization is most promising approach for
exploiting enzyme based processes in biotransformation,
diagnostics, pharmaceuticals and food industries.
• Several enzymes have been immobilized in variety of forms
including penicillin G, lipase, amylase, invertase.
• Research should be focused to overcome the current limitations
related to immobilization technique, so as to expand the horizon
from all around application
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