IN THIS EXPERIMENT YOU WILL…
Grow, isolation and identification fast growing bacteria known as ABC cultures found in yoghurt. These bacteria species are responsible for the clotting and thickening of milk in yoghurt.
This group of bacteria can grow in aerobic conditions (oxygen present) and rely on lactose to grow. Students will use 2 set of growth media (1 normal and 1 selective) so that they can determine which microorganism is the lactobacilliLactobacillus is a genus of Gram-positive, facultative anaerobic or microaerophilic, rod-shaped, non-spore-forming bacteria. They are a major part of the lactic acid bacteria group (i.e., they convert sugars to lactic acid). organism originating from the yogurt sample.
When classifying bacteria, microbiologists look at 3 properties:
- PeptidoglycanPeptidoglycan, also known as murein, is a polymer consisting of sugars and amino acids that forms a mesh-like layer outside the plasma membrane of most bacteria, forming the cell wall. layer in surface membrane ( AKA gram negative or positive) and other structure characteristics
- Aerobic or anaerobic bacteria
- Sugars used as an energy source
The bacteria that will be grown are lactobacillus (lactose digesting bacteria that are rod shaped and can survive in aerobic conditions).