Fermenters (Cambridge (CIE) O Level Biology): Revision Note
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
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