Immobilised lactase used to make lactose-reduced milk

This simple practical investigation introduces students to the principles of digestion and enzyme immobilisation.

It can be used as the starting point for numerous more advanced activities such as the regulation of lactase production in Escherichia coli (the lac operon), the evolution and social significance of lactose tolerance in humans and the use of enzymes in food production.

Languages available: uk1



Educational objectives
Students will learn about the basic biochemistry of lactose digestion and how to immobilise enzymes in calcium alginate. There are also opportunities for additional problem-solving activities.

Pre-knowledge and skills required by students
A basic knowledge of the properties of enzymes and the structure of carbohydrates would be useful, although it is not essential.

Time taken in lesson
40 minutes

Preparation time
30 minutes

Specialist equipment and materials required
Lactase enzyme, sodium alginate. Other items are available from supermarkets and high-street pharmacies.

Context where originally used
Used with students aged 10–16.

Additional information
The NCBE supplies Novozymes enzyme products to schools and colleges in the UK. Similar arrangements may exist in other countries. Sodium alginate is available from suppliers of laboratory chemicals (it is also widely used in the food industry).

Dean Madden

Author's address
NCBE, Science and Technology Centre
University of Reading
Earley Gate

Copyright holder(s)
Copyright © Dean Madden 2007


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