ISOLATION Of AIR BORNE MICROORGANISM-SETTLING PLATE METHODS

 

ISOLATION Of AIR BORNE MICROORGANISM-SETTLING PLATE METHODS

 

AIM:

To isolate the air borne microorganisms by specific techniques.

PRINCIPLE :

The Isolation of Microorganism From Air is performed by using the settle-plate technique. In this method a suitable medium is poured over a sterile petri dish and then allow it to slidify. After that the plate is exposed to the open air for a few minutes. Then the plates are incubated for the formation of microbial colonies on the plate. Observe the colonies by using a microscope.

Czapek medium, also known as Czapek’s agar (CZA) or Czapek-Dox medium. This media is used for propagating fungi and other organisms.Czapek medium is composed of  iron sulfate(0.01g), potassium chloride (0.5g),  magnesium sulfate(0.5g), monopotassium phosphate(1g), cane sugar(30g),  sodium nitrate (2g) and distilled water (1000 lit).The  Czapek-Dox agar is an optimum growth medium for Aspergillusbrasiliensis, Candida albicans, Saccharomyces cerevisiae, Aspergillusniger.

The Nutrient agar medium Is used to grow both spore-forming and non-spore-forming gram-negative cocci, gram-positive bacilli, and gram-negative bacilli.

MATERIALS REQUIRED:

·         Czapek-Dox agar medium with rose bengal (For fungal cell isolation).

·         Nutrient Agar (NA) medium.

·         Streptopenicillin.

·         Sterile petri dishes.

·         Sterile syringe and needles.

·         Colony counter.

·         Burner or spirit lamp.

 

PROCEDURE:

1.  Prepared the Czapek-dox agar medium and NA medium.
2.        Pour the melted Czapek-dox agar medium with streptopenicillin and NA medium in a petri dish.
3. Keep them at room temperature in a steady condition to allow them to solidify.
4.  After solidification remove the covers of petri plates and expose them to the air for 5-10 minutes
5.      After 5-10 minutes cover these plates.
6.  Incubate the Czapek-dox agar plates at 25 degrees centigrade for 2-7 days whereas NA plates at 37 degree centigrade for 24-48 hours.
7.    After incubation, observe the colony formation on both plates (Czapek-Dox medium and NA medium) and count them

RESULT

 :

After incubation,count the number of colonies were counted.

 DISCUSSION:

In the settle-plate method, horizontally expose a petri dish containing agar medium for 5-10 minutes. After that the plates are incubated and count the appeared colonies over the plate. In this practical we will isolate the microbes from air by using the settle-plate method.Among these air-borne particles, the fungal spore is considered as the most important air-spora. The air is a good carrier for microorganisms but not a good medium for their growth