Microorganisms in Industrial Fermentations (Leaving Cert Biology): Revision Notes

Microorganisms in Industrial Fermentations

Key Points about Industrial Fermentations:

• Micro-organisms Used:
  • The main micro-organisms used are bacteria and fungi, especially yeast.
  • Although plant and animal cells can be used, micro-organisms are preferred due to their efficiency.
• Fermentation:
  • In industry, fermentation refers to the production of useful products by micro-organisms, with or without oxygen.
• Bioreactors:
  • Industrial fermentations are carried out in bioreactors (large vessels designed for fermentation).
  • To ensure the product is properly formed, specific conditions must be maintained:
  1. Correct nutrients and micro-organisms must be used.
  2. Temperature and pH must be kept at suitable levels.
  3. Oxygen may or may not be required, depending on the process.
  4. A sterile environment is essential to prevent contamination.
  5. The mixture is usually stirred or agitated to ensure even distribution of nutrients and conditions.

Micro-organisms Used in Bioprocessing:

1. Yeast:

• Used to produce beer and wine through alcohol fermentation.
• Produces carbon dioxide to help dough rise in bread making.

2. Bacteria and Yeasts (Traditional Products):

• In the past, bacteria and yeasts were used to produce:
• Yoghurt
• Cheese
• Vinegar
• Soy sauce
• Antibiotics

3. Genetically Altered Micro-organisms:

• More recently, bacteria, yeasts, and fungi have been genetically modified to produce a wide variety of products, including:
• Solvents
• Amino acids
• Vitamins
• Drugs
• Food additives
• Enzymes to break down stains (e.g., in detergents).
• Fuel such as biogas.
• Flavourings for food products.

4. Immobilised Micro-organisms:

• Immobilised E. coli is used in water treatment to detoxify sewage in waste water.

Importance of Micro-organisms in Industrial Fermentations:

1. Micro-organisms play a key role in producing a wide range of products used in food, medicine, and industry.
2. Advances in genetic engineering have expanded the range of products that can be made using micro-organisms.
3. They are cost-effective, efficient, and environmentally friendly.