Microbiology: organisms in industry

Nature of science:

Serendipity has led to scientific discoveries—the discovery of penicillin by Alexander Fleming could be viewed as a chance occurrence. (1.4)

• Microorganisms are metabolically diverse.
• Microorganisms are used in industry because they are small and have a fast growth rate.
• Pathway engineering optimizes genetic and regulatory processes within microorganisms.
• Pathway engineering is used industrially to produce metabolites of interest.
• Fermenters allow large-scale production of metabolites by microorganisms.
• Fermentation is carried out by batch or continuous culture.
• Microorganisms in fermenters become limited by their own waste products.
• Probes are used to monitor conditions within fermenters.
• Conditions are maintained at optimal levels for the growth of the microorganisms being cultured.

Applications and skills:

• Application: Deep-tank batch fermentation in the mass production of penicillin.
• Application: Production of citric acid in a continuous fermenter by Aspergillus niger and its use as a preservative and flavouring.
• Application: Biogas is produced by bacteria and archaeans from organic matter in fermenters.
• Skill: Gram staining of Gram-positive and Gram-negative bacteria.
• Skill: Experiments showing zone of inhibition of bacterial growth by bactericides in sterile bacterial cultures.
• Skill: Production of biogas in a small-scale fermenter.

• Alexander Fleming discovered penicillin in England in 1928, on a discarded petri dish. To what extent was Dr Fleming’s discovery a lucky observation, or do we only perceive what we are open to?

Utilization:

• Syllabus and cross-curricular links:
• Biology
• Topic 2.1 Molecules to metabolism
• Topic 4.3 Carbon cycling
• Topic 6.3 Defence against infectious disease