June 28, 2019
Production of Bread
Anaerobic respiration from yeasts are used to produce bread.
glucose (C6H12O6) → ethanol + carbon dioxide
Carbon dioxide gas released from this fermentation reaction is what makes the bread rise.
Production of Yogurt
- Lactobacillus is a type of bacteria that plays an important role in the production of yogurt.
- Milk contains a type of sugar called lactose. Lactobacillus breaks down lactose into lactic acid.
- The lactic acid lowers the pH of the milk so that milk proteins are denatured and give the texture of yogurt.
Industrial Fermenter
An industrial fermenter is large vessel that can be used to produce large numbers of bacteria and fungi.
Examples of products that can be produced in industrial fermenters:
- human insulin from genetically modified bacteria
- penicillin (a type of antibiotic) from Penicillium
- mycoprotein (protein derived from fungi) from Fusarium
👇 For IGCSE Biology, you should understand the design of industrial fermenters. 👇
- Sterile nutrient medium: Microorganisms need nutrient to grow and reproduce. The nutrient medium has to be sterile in order to avoid any contamination from unwanted microorganisms.
- Air inlet: Microorganisms need oxygen for aerobic respiration, so an optimal concentration of oxygen should be maintained inside the fermenter for microorganisms to grow. The oxygen concentration probe monitors the oxygen concentration inside the fermenter.
- Cooling jacket with cold water: Heat is produced from the respiration of microorganisms. Since enzymes will be denatured and thus microorganisms killed at high temperature, optimal temperature must be maintained for maximum growth of microorganisms. The temperature probe monitors the temperature inside the fermenter. The temperature can be adjusted by letting cold water flow through the cooling jacket.
- Acid/alkali: Since enzymes will be denatured outside of their optimal pH range, the optimal pH must be maintained for more microorganisms to grow. The pH probe monitors the pH inside the fermenter. The pH can be adjusted by adding either acid or alkali.
- Stirrer: The stirrer keeps mixing the medium so that nutrients, oxygen and heat are evenly distributed throughout all parts of the fermenter.