Preparation and use of an immobilised enzyme

Background:

Immobilised enzymes: enzymes that are attached to an inert material.

Materials:

• Sodium alginate
• Water
• Yeast
• Beaker
• Glass stirring rod
• Syringe
• Calcium chloride solution
• Sieve
• Distilled water

Method:

i) Prepare enzyme immobilisation

1. Sterilise all glassware in advance of conducting the experiment to ensure no contamination from micro organisms.
2. Mix sodium alginate, water, and yeast in a beaker.
3. Use a glass stirring rod to stir the mixture and form a paste.
4. Draw the mixture into a syringe.
5. Release the mixture from the syringe, one drop at a time, into a calcium chloride solution. Beads containing yeast cells will form.
6. Leave the beads to harden.
7. Filter the beads through a sieve and rinse with distilled water to remove any excess free enzyme.

ii) Application of the immobilised enzyme-production of glucose from sucrose

8. Mix yeast and water, then pour into a separating funnel (free yeast).
9. Place the beads into another separating funnel (immobilised yeast).
10. Pour sucrose solution into each of the separating funnels.
11. Immediately test samples from each funnel for glucose using Clinistix.
12. Repeat the test at intervals until glucose appears in both funnels.
13. Record the results.
14. Run off the remaining product from each funnel into beakers.
15. Compare the turbidity of the solutions from both funnels.

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