Immobilising Enzymes - Biotechnology

Question 1

Adsorption

Answer 1

Enzyme binds to imobilising support due to hydrophobic interactions and ionic links. Bonding force not that strong so leakage can occur. E.g porous carbon, clays and resins. Substrate easily available so fast reaction rates.

Question 2

Covalent Bonding

Answer 2

Enzymes are covalently bonded to support. Binding is very strong so leakage is rare.

Question 3

Entrapment

Answer 3

Enzymes trapped in network of gel bead/cellulose fibres. Reaction rates can be reduced as substrate has to get through barrier (active site is less available).

Question 4

Membrane Seperation

Answer 4

Physically seperated from substrate mixture by partially permeable membrane that substrates can pass through as they are small enough. Product molecules are small enough to exit.

Question 5

Advantages of Immobilisation

Answer 5

Enzymes not present with products so purification costs reduced. Enzymes immediately available for reuse, which is useful in continuous batch. Immobilised enzymes are more stable as a matrix protects them, therefore less likely to be denatured.

Question 6

Disadvantages of Immobilisation

Answer 6

Immobilisation requires additional time, equipment and materials so more expensive to set up. Enzymes can be less active as they do not mix freely with substrate. Any contamination is costly as the whole system needs to be stopped.