Role of Enzymes in Pharmaceutical Biotechnology
Enzymes act as biological catalysts, accelerating chemical reactions in drug manufacturing and diagnostics with high specificity and efficiency under mild conditions.
In pharmaceuticals, enzymes are used to:
Synthesize complex molecules (e.g., chiral intermediates, antibiotics, drug precursors).
Facilitate diagnostics as key components in diagnostic kits.
Modify drugs through conjugation and other reactions.
Why Immobilize Enzymes?
Free enzymes in solution pose challenges such as:
Difficulty in separation from the final product.
Sensitivity to denaturation under process conditions.
High costs due to limited reusability.
Immobilization
Attaching enzymes to a support or trapping them in a matrix—enhances enzyme stability, enables reuse, and improves cost-effectiveness for industrial applications.
Methods of Enzyme Immobilization
1) Adsorption
The enzyme is physically adsorbed onto a solid support (e.g., activated charcoal, silica, glass beads).
Advantages: Simple, inexpensive, minimal impact on enzyme activity.
Disadvantages: Weak bonding, enzyme may leach out.
2) Covalent Binding
The enzyme is chemically bonded to a solid carrier (e.g., polymers, glass, cellulose).
Advantages: Strong bonding, high stability.
Disadvantages: May alter enzyme activity, complex process.
3) Entrapment (Encapsulation)
The enzyme is physically trapped in a gel or polymeric network (e.g., alginate beads, polyacrylamide gel).
Advantages: Protects enzyme, good stability.
Disadvantages: Diffusion limitations, may restrict enzyme movement.
4) Cross-Linking (Co-aggregation)
Enzymes are chemically linked using cross-linking agents (e.g., glutaraldehyde).
Advantages: High stability, resistance to extreme conditions.
Disadvantages: Loss of enzyme activity due to chemical modification.
5) Encapsulation in Membranes
Enzymes are enclosed within semi-permeable membranes (e.g., liposomes, polymer membranes).
Advantages: Protects enzyme from degradation, allows controlled release.
Disadvantages: Complex preparation, possible enzyme leakage.
Applications of Immobilized Enzymes in Pharmaceuticals
Antibiotic Production: Immobilized penicillin amidase is used in the synthesis of semi-synthetic penicillins.
Lactose-Free Pharmaceuticals: Lactase enzyme immobilization helps in lactose hydrolysis for lactose-intolerant patients.
Biosensors: Enzyme-based biosensors help in glucose monitoring for diabetic patients.
Prodrug Activation: Immobilized enzymes help convert prodrugs into their active forms.
