CULTURE TECHNIQUES IN MICROORGANISMS

 Bacteria, fungi and Algae can replicate in human. Hence, cultured differently. They are cultured in a test-tube.

However, the culture medium used for growing most micro-organism consist of

*Agar, jelly like material obtain from the sea-weed 

* Various nutrient commonly in form of yeast extract, vegetables extract and beef extract. 

Agar liquifies easily on heating and solidifies on cooling below 45 °C. Micro organism would not grow on agar except nutrients are added. It is not affected by enzymes produce by microorganisms. Therefore, it an ideal solid mixture for culture.

Method of  preparing culture solution.

i. A solution called *AGAR* is prepared under sterile Condition

ii  Then pour into a sterile petri-dish

iii. Allow to cool and set in petric dish

iv. A heat steriliser may be used to kill micro-organism in the pertic dish

v. The material is then introduce and covered immediately

vi. Place the petric dish in a warm but dark compartment or an incubator

vi. Observe the record you have seen for 2-3days

PRECAUTIONS:

a. Wash your hands with soap and water before and after  the preparation of agar solutions

b. Open petric-dish slightly and cover at once

c. Open petric-dish firmly with adhesive tape

d. You should perform the experiment if sick

e. Avoid talking, coughing, sneezing and do not touch infected jelly

vi. Unused agar should be sterilised by washing with antiseptic soap and disinfected, e.g 40% folmadehyde . Heat can also be used to sterilise

vii. All instrument should be sterilised before use

IDENTIFICATION OF MICRO-ORGANISM

MICRO-ORGANISM can be seen and identify in the pond, river, stream and air.  

To identify it the following procedures must be followed.

1. Get a five petric dishes lebelled K, L,M, N and O respectively

2. Expose petroc dish *K* to air about 10-15minute and then cover it

3. Put in petric dish *L* a few drops of pond water and cover it 

4. Put in petric-dish *M* a few drop of river water and cover it

5. Put Petri-dish *N* a few drop of stream water and cover it.

6. Allow petric-dish O to serve as control (that is do not introduce anything to it)

7. Leave you petroc-dishes in the laboratory for 3-4days

8. Observe all the petric-dishes for any development and note any difference in each petric-dish

9. Record the characteristics that's color, pattern of growth, appearance...of colonies of micro-organism in each of the petric-dishes