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1. Isolation and screening of
Potential microbes from different
environmental source…
M.Phool Badshah

2. Microbes Isolation from Different
environments:
 Soil water.
 Slag water.
 Food sample.
 Milk sample.
 Purpose:
I. To isolate antibiotic production microbes ( Bacteria) from
sample.
II. To isolated degradable microbes (bacteria), to removed
contamination and to keep and clean the environment.
III. To isolated infected or pathogenic microbes( Bacteria)
from food water and milk samples.

3. Serial Dilution method:
I. Serial dilution method is one of the most usable method
which is used for the isolation of bacterial colony.
II. In this method we take concern samples (milk, food, slag,
soil water) make its dilution in test tubes.
III. We inoculated the sample from the diluted test tubes in
the prepared nutrient agar plates by using pour plate
method and then incubated the culture plates at 37’C for
24 hours.
IV. After 24 hours we absorb the culture plates, the growth
will appear on each plates.
 Now we performed sub-culturing method for the
isolation of pure culture. After isolation of pure culture we
perform gram staining method and other biochemical test
for the conformation and identification of bacterial
species.

4. Materials:
 Samples ( Soil, Food, Milk, Slag and Tap water)
 Saline solution or Distilled water.
 Nutrient agar.
 Beaker.
 Flask.
 Aluminum Foil.
 Cotton.
 Micropipette.
 Autoclave.
 Incubator.
 Test tubes.
 Test tube stand.
 Media plates.

5. Procedure:
I. Collected desired samples (soil, tap water, slag water,
milk, food ) from the environment.
II. Take 8 test tubes and take 10ml of saline in first tube
and take 9ml distilled water in each the remaining test
tubes and then labeled each test tubes.
III. Take 1 gram of samples (soil, food, slag, milk) and make
solution in first test tube which having 10ml of saline
solution . Which will called master test tube.
IV. Distribute the sample solution from first test tube
(master test tube) in the remaining test tube.
 Take 1ml of sample solution from 1st tube (master
tube) and put in 2nd test tube.
 Take 1ml of sample solution from 2nd tube and put
in 3rd test tube.

6. f
 Take 1ml of sample solution from 3rd tube and put in 4th
test tube.
 Take 1ml of sample solution from 4th tube and put in 5th
test tube.
 Take 1ml of sample solution from 5th tube and put in 6th
test tube.
 Take 1ml of sample solution from 6th tube and put in 7th
test tube.
 Take 1ml of sample solution from 7th tube and put in 8th
test tube.
I. Prepare nutrient agar media.
II. For pouring the samples in the media plates we use
“Pouring Plate Method”.
III. By using micropipette we take 0.5ml sample solution
from the desire test tubes and pouring on media plates
by Pouring Plate Method.

7. b
 First we pouring the sample solution in the test tubes and
then pouring the Nutrient agar in the plates , and labeled
the plates also.
 Allow the plates to solidified and then we replaced the
inoculated media plates in the incubator at 37’C for 24
hours.
 After 24 hours we absorbed the culture plates, the growth
of the microbes will b appeared on the media plates.
 Next we perform sub culturing for the isolation of pure
plates.
 Again we prepare new fresh nutrient agar pouring the
media in the plates. Allow the plates to solidified and then
we pick up a single colonies for each growth culture plates
and inoculated on fresh nutrient agar plates by using
streaking method.
 After striking replaced the inoculated plates in the
incubator at 37’C for 24 hours.

8. s
 After 24 hours a pure, clear and visible colonies will appear
on each plates.
 Note:
As the same method we can isolated microbes from slag,
food and milk samples.
We use the same method and same procedure for the
isolation of microbes from these samples.

9. s

10. Isolation of Microbes from Air:
Materials:

11. Procedure: