ISOLATION OF ANTIBIOTIC-PRODUCING

MICROORGANISMS

T.Monirah Alhammadi

There are several ways to isolate microbes

that produce antibiotics from the soil. Below are some methods used to isolate microbes produce antibiotics effective against some microbes

PRINCIPLE

Random Isolation in pure

cultur

crowded-plate

Catrer and lockwood method

Isolation of Antagonistic soil microorganisms

#soil isolation agar plate

pure culture test each culture against Plant Pathogenic

microbes inhibition zone # Demonstrates the effectiveness of

the microbe isolated from the soil against the microbe pathological

1-Random Isolation in pure cultur

1-Random Isolation in pure cultur

#fungus pathological pollination

growth media Incubate plates

#Then sprinkle dishes of soil dilution 1 \ 1000 to 1 \

100000 approximately 0.6 cm Incubate plates

Tset the plate inhibition zone

2 -Catrer and lockwood method

Catrer and lockwood method

]In this experiment , we will use the

crowded-plate technigue for isolation of antibiotic-producing microorganisms from soil

3-crowded-plate

#Soil suspensions(1:500 dilution of soil

sample suspension) #cultures of E.coli, S.aureus, (P.aeruginosa

#test tube #petri dishes

#1-ml and 5-ml pipettes #bunsen burner

#sterile water

Materials

1 -label three test tubes 1,2and3. with apipette , add 5ml of tap water to eash tube.

2 -shake the provided 1:500 soil sample thoroughly for 5 minutes to effect a uniform soil-water suspension.

3 -using a 5-ml pipette , transfer 5 ml from the 1:500 dilution to tube 1 and mix . The final dilution is 1:1000

4-using another pipette , transfer 5 ml from tube 1 to tube 2 and mix.

The final dilution is 1:20005-using another pipette , transfer 5 ml from tube 2

to tube 3 and mix. The final dilution is 1:4000

Methods:

.6-Using separate 1-ml pipettes , transfer 1 ml of the 1:1000, 1:2000

Dilutions to their appropriately labeled petri dilutions

agar ) trypticase soy ) 7- pour one tube of molten

8 -incubate all plates in an inverted position for 2 to 4 days at 25C

Methods:

THE END