Bacterial Growth Requirement

Bacterial Growth Requirement:-

Cultivation of Bacteria:

Culturing of Bacteria:

Culturing is a technique used to isolate a microorganism in a pure culture and used for testing the sensitivity to an antibiotic i.e. to determine the suitable antibiotic for certain microorganism.

e.g. to isolate organism from a specimen, you need culture media, then inoculate the specimen (e.g. urine) by a needle in a zigzag form, then incubate at temperature 37˚C, after 24 hours you see organism growing in pure form, i.e. you found only one type, otherwise it is mixed.

The medium of culturing must contains:

1- Carbon source: carbohydrate, organic salts

2- Nitrogen source: peptone = Digestive protein. Amino acids

3- Essential vitamins (growth factor)

4- Minerals (growth factor)

5- Essential amino acids: in meat extract(beef).

- These ingredients are dissolved in distilled water, the pH is adjusted to 7.2 and then the medium should be sterilized (e.g. by Autoclave).

- Medium is either solid or liquid and some times semisolid.

Solid medium: used for isolation in pure form.