Topic 2: Cultivation of Bacteria
- Bacteria must be grown on culture media in order to characterize and identify.
- Bacteria require sources of energy, carbon, nitrogen, minerals, and growth factors
- Most bacteria are chemoheterotrophs
- require organic compounds for carbon and energy sources
- Bacteria exhibit a wide range of nutritional requirements, need enriching nutrients
- milk, serum, blood, tomato juice
- Growth factors: organic compounds such as vitamins or amino acids that are incorporated into a cell without alteration
- First bacterial cultures were grown in broth/liquid media - infusions and blood
- Robert Koch attempted to culture bacteria on potato slices when he realized need for solid media.
- Added gelatin to liquid media when some bacteria wouldn’t grow on potato → however, gelatin liqueified under incubation conditons
- Angelina Hess suggested use of agar as solidfying agent
- Today, agar is the most commonly used solidifying agent in culture media
- Aseptic technique is used in microbiology to exclude contaminants
- prevention of unwanted microorganisms in laboratory and medical procedures
