1. Isolation of microorganisms
Lab 8
Abeer Saati

2. Isolation of microorganisms
Bacteria are everywhere. In water, soil and food, on your skin, and intestinal tract normal flora. The human body has billions of bacteria which creates the normal flora fighting against the invading pathogens.

3. Serial dilution (Isolation from soil)
Make dilution from10-1 to 10-4 using sterile distilled water. Only one ml of each dilution will transfer to Petri dishes with potato dextrose agar (PDA) media for fungi and N.A. for bacteria.
Spread soil directly on top of multiple Petri dishes containing the same medium to consider any missing fungal species. All the samples will incubate for 7 days at 28C for fungi and 24 hour at 37C for bacteria.

5. Purification of microorganisms
- Prepare the suitable media (Nutrient agar for bacteria) potato dextrose agar for fungi.
- Make discs from each recovered fungi and transfer to fresh PDA plates, one species in each dishes, and incubate it for 7 days at 28˚C.
- With the sterile needle, collect bacteria from one colony by touching the bacterial growth and transfer to fresh N.A plates, one species in each dishes, by using streak plate method and incubated for 24 hour at 37˚C.

6. Purification of microorganisms
Importance of Streaking streaking is a technique used to isolate a pure strain from a single species of microorganism, often bacteria. Samples can then be taken from the resulting colonies and a microbiological culture can be grown on a new plate so that the organism can be identified, studied, or tested. Types of streak plate (quadrant streak and simple streak)

7. Procedure
1. Sterilize the inoculating loop in the bunsen burner until it is red hot. Allow it to cool.
2. Pick an isolated colony from the agar plate culture and spread it over the first quadrant (approximately 1/4 of the plate).
3. Flame the loop.
4. Turn the plate 90, then streak into the next quadrant without overlapping the previous streaks.
5. Flame the loop.
6. Turn the plate 90°, and streak into the next quadrant as in step 4.
7. Flame the loop.
8. Repeat streaking the remainder of the plate.
9. Invert the plate and incubate at 37°C for 24 hr.

8. Characterization of microorganism
Fungi Culture Fungi Microscope Fungi Picture
Aspergillus

9. Characterization of microorganism
Penicillium

10. Characterization of microorganism
Shapes of bacteria

11. Thank You