Some types of bacteria and fungi can be grown to produce antibiotics on a large scale.
An example of this is pencillin. Pencillin is grown in fermenters using a type of mould known as penicillium.
It is grown in a liquid culture medium, containing both sugar and other nutrients.
As the mould grows, the sugar is used up.
The mould only starts to produce penicillin once most of the nutrients have been used up for growth.
Mycoprotein means 'food from fungi'.
It is a type of single-celled protein which can be used as a meat substitute in vegetarian meals, such as Quorn.
The main source of mycoprotein is Fusarium. This is grown in fermenters, using glucose syrup as food.
It is supplied with oxygen as it respires aerobically, and nitrogen, in the form of ammonia, alongside other nutrients.
Enzymes and food production
Some foods, such as cheese, are made using enzymes. To make a large quantity of the food, you will require loads of the enzyme.
Traditionally, cheese is made using Rennin, an enzyme from the lining of the calf's stomach.
However, Rennin can now be produced using genetically modified organisms in a large quantity, and can therefore be used a vegetarian substitute.