Application of Enzymes in Daily Life

Enzymes in the food industry

Enzymes in detergents and medicine

Biological washing powders contain protease, which breaks down protein-based stains such as blood and egg, and lipase, which breaks down fat and oil stains. These enzymes work effectively at relatively low washing temperatures, which saves energy compared with using very hot water alone.

In medicine, enzymes are used in diagnostic test kits, for example glucose oxidase strips that detect glucose in urine or blood for diabetes monitoring. Some enzyme preparations are also given to patients who cannot produce enough digestive enzymes of their own, to help them digest food properly.

Immobilised enzymes

An immobilised enzyme is fixed onto or within a solid support material, such as beads of alginate gel, instead of being left free in solution. This allows the enzyme to be reused repeatedly, kept separate from the product so it does not contaminate it, and easily removed from the reaction mixture, which makes industrial processes more economical and efficient.

How it is examined

Exam questions typically name an industrial or household application and ask you to identify the enzyme involved and explain its role, or ask you to explain why using an enzyme is more efficient than the equivalent non-enzymatic process. You may also be asked to explain one advantage of using an immobilised enzyme over a free enzyme in an industrial process.

Worked exam-style question

Question. A food company wants to produce clear apple juice cheaply and in large amounts. It adds the enzyme pectinase to crushed apples, and it fixes the enzyme onto small gel beads packed into a column, so the juice flows through and out the bottom.

(a) State the role of pectinase in making apple juice. (b) The enzyme is fixed onto beads rather than mixed freely into the juice.

State the name given to an enzyme used in this way. (c) Give two advantages to the company of fixing the enzyme onto beads.

(d) Explain why the column is kept at a warm temperature but not made very hot.

Model answer. (a) Pectinase breaks down pectin in the crushed apples, which clarifies (clears) the juice and increases the volume of juice released. (b) It is an immobilised enzyme.

(c) Any two: the enzyme can be reused repeatedly; the juice is not contaminated by the enzyme, so less purifying is needed; the enzyme is easily separated from the product; the process can run continuously. (d) A warm temperature near the enzyme's optimum gives a fast rate of reaction; a very high temperature would denature the enzyme, changing the shape of its active site so the substrate no longer fits and the reaction stops.

Practice question

Try this. Biological washing powders contain protease and lipase and are recommended for washing at warm rather than boiling temperatures. Explain, in terms of enzymes, why washing at a warm temperature is effective but washing in boiling water would not be.

Exam tip

Key terms

These terms are needed to explain any enzyme application:

• Enzyme, a biological catalyst that speeds up a specific reaction.
• Substrate, the molecule an enzyme acts on.
• Active site, the part of the enzyme the substrate fits into.
• Denaturation, the loss of enzyme shape and activity at high temperature or extreme pH.
• Fermentation, the enzyme-driven anaerobic process used in brewing and baking.

Source:SRC-DSKP-EN

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