A fermenter is a huge sterile steel vessel in which bacteria or fungi grow under carefully controlled conditions. This is how insulin, penicillin and mycoprotein are made on a large scale. The whole lesson is Extended content.
Extended. Fermenters are large, sterile vessels used to grow bacteria and fungi on a large scale so they make useful products such as insulin (genetically modified bacteria), penicillin (the fungus Penicillium) and mycoprotein (the fungus Fusarium). The conditions are controlled: temperature, pH, oxygen, nutrient supply and removal of waste products, so the microorganisms grow fast and give a high yield.
Extended. Click each part of the fermenter to see what it does. Then choose a product: insulin, penicillin or mycoprotein. The graph shows growth over 48 hours as a percentage of the maximum.
| Product | Made by | Use |
|---|---|---|
| insulin | genetically modified bacteria carrying the human insulin gene | treating people with type 1 diabetes |
| penicillin | the fungus Penicillium | an antibiotic; made after the main growth phase |
| mycoprotein | the fungus Fusarium | a protein-rich food for people |
Four quick checks. Each correct answer earns XP and records this skill on your profile.
Extended: in the sim, which part of the fermenter keeps the temperature at the optimum?
Extended: which organism makes penicillin in the fermenter sim?
Extended: what happens to the growth curve when oxygen is not supplied?
Extended: why is the air pumped into a fermenter sterile?
Extended. Use the condition chips to remove one control at a time (no temperature control, no pH control, and so on) and watch the growth curve. Each failure lowers the yield for a different reason.
| Condition | How it is controlled | Why it matters |
|---|---|---|
| Temperature | water jacket; cold water carries heat away | respiration releases heat; too hot and the enzymes are denatured, too cold and growth is slow |
| pH | pH probe; acid or alkali added | waste products change the pH; enzymes work best at their optimum pH |
| Oxygen | sterile air bubbled in | needed for aerobic respiration; without it growth is much slower |
| Nutrient supply | nutrient inlet adds sugars and a nitrogen source (e.g. amino acids) | food for respiration and for making new cells and products |
| Waste products | waste gas outlet lets carbon dioxide escape | wastes build up, become toxic and change the pH |
The water jacket cools the fermenter. The microorganisms release heat by respiration, so without cooling the temperature would rise and denature their enzymes.
Unlocks once the four checks above are done. Worth more XP, written to IGCSE Paper 2 and Paper 4 standard.
Extended: why does the temperature inside a fermenter rise if it is not controlled?
Extended: the pH probe in a fermenter shows that the pH is falling. What is the most likely cause?
Extended: which product is made in a fermenter by the fungus Fusarium?
Extended: why is the fermenter stirred continuously?
This skill is now recorded on your profile. Keep the chain going.