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