Enzyme Immobilization

Definition

• Enzyme immobilization is the phenomenon where enzymes are attached to an inert insoluble material.

Methods of Enzyme Immobilization

• There are several methods to achieve enzyme immobilization:
  1. Adsorption
  2. Ionic Binding
  3. Covalent Binding
  4. Entrapment Method

1. Adsorption

• Process: Binding of enzymes onto inert carriers (e.g., activated charcoal, silica, clay).
• Forces Involved: Weak attractive forces such as:
  • Hydrogen bonding
  • Van der Waals interactions
• Effects on Activity: Enzyme activity generally remains unaffected.
• Factors Influencing Binding: Changes in pH, ionic strength, and temperature can disrupt enzyme binding.

2. Ionic Binding

• Process: Utilizes ion exchange resins with positive or negative charges depending on pH.
• Common Materials:
  • DEAE cellulose (positive charge)
  • CM cellulose (negative charge)
• Factors to Maintain: pH, ionic strength, and temperature are crucial for successful binding.

3. Covalent Binding

• Process: Permanent binding via covalent bond formation between the carrier's functional group and the enzyme's amino acid side chains.
• Advantages:
  • Not affected by external factors such as pH and ion presence.
• Consideration: Ensure that the catalytic site of the enzyme remains unaffected during the process.

4. Entrapment Method

• Process: Enzymes are trapped in a gel matrix.
• Advantages:
  • Cost-effective
  • Gel can be reused multiple times
  • Easy recovery of enzymes post-reaction.