Bacterial aerobial culture techniques By Jwala Jayadeep KUFOS

1. BY JWALA
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2. CULTURE MEDIA
• A culture medium is a nutrient solution used to grow microorganisms.
• Two broad classes of culture media are used in microbiology: defined
media and complex media.
• Defined media are prepared by adding precise amounts of pure inorganic
or organic chemicals to distilled water. Therefore, the exact composition
of a defined medium (in both a qualitative and quantitative sense) is
known.
• Complex media are made from digests of microbial, animal, or plant
products such as casein, beef, soybeans, yeast cells, or any of a number
of other highly nutritious substances.

3. Methods for isolating pure cultures
• If the bacterial species being sought comprises a suitably high proportion of
the mixed population, it can be isolated in pure culture
• A variety of techniques have been developed whereby isolation into pure
culture can be accomplished. Each technique has certain advantages and
limitations and there is no one method that can be used for all bacteria.

4. Streak culture (surface plating)
It is the method routinely employed for the isolation of bacteria in pure
culture.

5. There are different types streak culture methods they are:-
i) Lawn culture or carpet culture:- :- It provides uniform surface growth of
the bacterium and is useful for bacteriophage typing and antibiotic
sensitivity testing (disc method).

6. i) Stroke culture:-It is used for providing a pure growth of bacteriuM for
slide agglutination tests.

7. iii) Stab culture:- Stab culture is employed mainly for demonstration of the
gelatin liquefactions and the oxygen requirements of the bacteria.

8. Pour plateculture
The pour plate method gives an estimate of the viable bacterial count in
a suspension.

9. Sweep plate method
The edges of the Petri dishes containing the culture medium are rubbed
over the fabric with the medium facing it. The dust particles stirred up
from the cloth get settled on the culture medium and colonies develop
on incubation.

10. Liquidcultures
Liquid cultures are preferred when large and quick yield are required.

11. Micromanipulator techniques
A device called micromanipulator can be used in conjugation with a
microscope to pick a single bacterial cell from a mixed culture.

12. REFERENCES
• PelczarTR M J Chan ECS and Kreig N R (2006). Microbiology.Fifth edition,
Tata McGraw-Hill INC. New York.
• Michael T. Madigan, John M. Martinko, Kelly S. Bender, Daniel H.
Buckley,David A. Stahl January 12, (2014)Brock Biology of
Microorganisms (14thEdition) ISBN-10:0321897390; ISBN-13:978-
0321897398.(Indian Edition (2017) ISBN-978-93-3258686-4)
• Dr. Mini KD, (2013) Microbiology (Microbiology& Immunology) (2nd
Edition), Zoological Society of Kerala.
• https://en.wikipedia.org/wiki/Microbiological_culture#:~:text=One%20
method%20of%20bacterial%20culture%20is%20liquid%20culture%2C,of%20
bacteria%20for%20a%20variety%20of%20downstream%20applications.