Industrial fermentersSpec 5.8
In short
An industrial fermenter is a large container in which micro-organisms are grown in large numbers to make a product such as a food, medicine or enzyme. Conditions are controlled for fast growth: aseptic precautions, nutrients, optimum temperature using a cooling water jacket, optimum pH, sterile air for oxygenation, and stirring paddles for agitation.
A fermenter is a large container in which micro-organisms are grown in large numbers to make a product such as a food, a medicine or an enzyme. The conditions are controlled so that the micro-organisms grow and make the product as quickly as possible.
(opens full size in a new tab)| Condition | Why it is needed |
|---|---|
| Aseptic precautions | The fermenter and nutrients are sterilised, so no other micro-organisms get in. Unwanted microbes would compete for nutrients, spoil the product or cause disease. |
| Nutrients | A supply of a carbon source such as glucose, plus nitrogen and mineral ions, so the micro-organisms can grow and make the product. |
| Optimum temperature | Enzymes work fastest at the optimum. Respiration releases heat, so a cooling water jacket keeps the temperature constant. Too hot would denature enzymes. |
| Optimum pH | Enzymes work best at the optimum pH. A probe monitors pH, and acid or alkali is added to keep it steady. |
| Oxygenation | Sterile air is bubbled in, so the micro-organisms can respire aerobically, release more energy and grow faster. |
| Agitation | Stirring paddles mix the contents, so nutrients, oxygen and heat are spread evenly and the micro-organisms are in contact with the nutrients. |
For each condition, say what it is and why it is needed. Mark schemes link it to growth: for example, the optimum temperature gives the fastest enzyme activity, so faster growth and more product.
Written and checked against the Edexcel IGCSE Biology (4BI1) specification · Updated October 2026