Use lactase and fermenters in large-scale biotechnology
Lactase produces lactose-free milk; fermenters grow microorganisms at controlled conditions to make products such as insulin, penicillin and mycoprotein.
Extended only (Supplement); Biology 0610, 2026–2028. Use the stated specimen features and evidence. Diagrams are schematic. Written practice is self-checked
Before you begin
- Know that genes are sections of DNA and that organisms use enzymes in cellular processes.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
What products form when lactase acts on lactose?
What you will learn
- Explain the use of lactase to produce lactose-free milk
- Describe how fermenters produce useful products at large scale
- Explain why temperature, pH, oxygen, nutrients and waste are controlled
Break lactose into smaller sugars
Lactase breaks lactose into glucose and galactose. Treating milk with lactase lowers its lactose content and produces lactose-free or reduced-lactose milk for people who cannot digest lactose effectively. The enzyme changes the sugar; it does not remove all other milk components.
Lactase can be added directly or immobilised in a processing system so it can be separated from the product and reused. Follow only the process detail stated in a question.
Grow microorganisms under controlled conditions
A fermenter is a vessel used to grow microorganisms such as bacteria and fungi at large scale. They can make useful products including insulin, penicillin and mycoprotein. The organism, nutrient supply and conditions depend on the product.
Temperature is controlled to keep enzyme activity and growth near a suitable range. pH affects enzyme activity; oxygen is supplied when the process requires aerobic growth; nutrients provide materials and energy; waste products are removed or controlled because they can inhibit growth or contaminate the product.
Connect control with production
Aseptic conditions help prevent contamination by unwanted microorganisms. Mixing can distribute oxygen and nutrients and maintain even conditions. Product may be harvested during or after growth depending on the process.
A fermenter does not make every product using the same organism or conditions. Explain the controlled factor and why it matters, and avoid inventing specific industrial settings that were not supplied.
Pause and explain
Why is pH controlled in a fermenter?
Worked example
A fermenter temperature rises above the optimum for a microorganism producing a useful protein. Explain why product output may fall.
Show the worked solution
- Relate temperature to enzymes and growth.
- Keep the explanation conditional on the organism’s optimum.
Answer At a temperature above the suitable range, enzymes may work less effectively or become denatured, reducing microorganism growth and product formation.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
Explain how lactase is used to make lactose-free milk.
Give me a hint
Name the substrate and products.
Compare my reasoning
- Lactase acts on lactose in milk.
- It produces glucose and galactose.
Lactase breaks lactose into glucose and galactose, reducing the lactose content of the milk.
Look for these in your work
- Enzyme action stated
- Products correct
Name three useful products made using large-scale fermentation by bacteria or fungi, as listed in the syllabus.
Give me a hint
Recall the named examples.
Compare my reasoning
- Insulin and penicillin.
- Mycoprotein is the third example.
Examples include insulin, penicillin and mycoprotein.
Look for these in your work
- Three products named
- Matches syllabus list
Explain why a fermenter controls oxygen, nutrient supply and waste products.
Give me a hint
Connect each factor to microorganism growth or production.
Compare my reasoning
- Oxygen may be required for aerobic growth; nutrients supply raw materials and energy.
- Waste can build up and inhibit growth or affect product quality.
Oxygen is supplied when the organism and process require it; nutrients provide materials and energy; waste products are controlled because they can inhibit growth or affect product quality.
Look for these in your work
- Oxygen role qualified
- Nutrient and waste roles explained
Common mistakes
- Calling lactase a fermenter product without describing lactose breakdown
- Saying oxygen must always be supplied for every product
- Ignoring contamination and waste accumulation
What can you explain now?
What products form when lactase acts on lactose?
Compare with the explanation
Glucose and galactose
Lactase hydrolyses lactose into these sugars.
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Make it stick
What does lactase do, which three fermenter products are named, and why are conditions controlled?
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.