Fermenters
Penicillin Production
- Penicillin was the first antibiotic, discovered in 1928 by Alexander Fleming
- He noticed that some bacteria he had left in a Petri dish had been killed by the naturally occurring Penicillium mould
- The penicillium mould produces a chemical to prevent it from being infected by certain types of bacteria
The Action of Penicillin
Penicillin produced by the fungus Penicillium inhibits bacterial growth
- The chemical was isolated and named penicillin
- Since the discovery of penicillin, methods have been developed to produce it on a large scale, using an industrial fermenter
A Fermenter
A diagram of an industrial fermenter used to produce large quantities of microorganisms.
- Fermenters are containers used to grow (‘culture’) microorganisms like bacteria and fungi in large amounts
- These can then be used for many biotechnological processes like producing genetically modified bacteria and the penicillium mould that produces penicillin
- The advantage of using a fermenter is that conditions can be carefully controlled to produce large quantities of exactly the right type of microorganism
Conditions in a Fermenter Table
| Condition | Why and how it is controlled |
| Aseptic precautions | Fermenter is cleaned by steam to kill microorganisms and prevent chemical contamination, which ensures only the desired microorganisms can grow |
| Nutrients | Nutrients are needed for use in respiration to release energy for growth and reproduction of the microorganisms |
| Optimum temperature | Temperature is monitored using probes and maintained using a water jacket. This ensures an optimum environment for enzymes to increase enzyme activity and prevent denaturation |
| Optimum pH | pH is monitored using a probe to check it is at the optimum value for the microorganism being grown. The pH can be adjusted using acids and alkalis |
| Oxygenation | Oxygen is required for aerobic respiration to take place |
| Agitation | Stirring paddles are used to ensure temperature, pH, nutrients, and oxygen are all distributed evenly throughout the fermenter |
| Waste | The contents are filtered to remove waste created by the microorganisms |
Mycoprotein – the process of creating food from a fungus
- The fungus Fusarium is cultured (grown) on an industrial scale in fermenters
- These fermenters are large vats that can be kept at the optimum pH and temperature for Fusarium to grow
- The fungus is grown in aerobic conditions (it is provided with oxygen) and provided with glucose syrup as a food source (to allow the fungus to respire)
- The fungus grows and multiplies within the fermenter
- The fungal biomass is then harvested and purified to produce mycoprotein
- Mycoprotein is a protein-rich food suitable for vegetarians eg. it is used in QuornTM products
Production of Insulin
- Genetic modification is changing the genetic material of an organism by removing or altering genes within that organism, or by inserting genes from another organism
- The organism receiving the genetic material is said to be ‘genetically modified’, or is described as a ‘transgenic organism’
- The DNA of the organism that now contains DNA from another organism as well is known as ‘recombinant DNA’
- The gene for human insulin has been inserted into bacteria which then produce human insulin which can be collected and purified for medical use to treat people with diabetes
