Factors Affecting the Growth of Penicillium (WJEC GCSE Biology)

Factors Affecting the Growth of Penicillium

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 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

• The process works as follows:

  • A starter culture of the fungus Penicillium is added to the fermenter

  • The culture is added to a liquid nutrient medium

  • The conditions are controlled to maintain an optimum growth environment

    • temperature

    • pH

    • oxygen supply

    • nutrient supply

  • After a period of time, an antibiotic is secreted from the fungus

  • The culture medium is incubated and then filtered to remove the fungus. The antibiotic is then extracted 

A fermenter diagram

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