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ANTIBACTERIAL ACTIVITY OF BACTERIOCIN PRODUCED BY

LACTIC ACID BACTERIA

PRESENTED BYU. Jegadheeswari

II M. Sc MicrobiologySt. Mary’s College, Thoothukudi

Milrially diluted up to 9 dilutions using sterile distilled water

Fl of the sample was plated on the sterile Deman Rogosa Sharpe agar

ion and incubated at 37°c for 48 hours.

After incubation well isolated typical colonies were formed.

• The positive culture from the selective agar were taken for the following confirmation test.

1. Microscopic observation

2. Bio chemical Characteristics

IDENTIFICATION OF Lactobacillus sp

• MICROSCOPIC OBSERVATIONS:

1. Gram’s staining test were performed for the identification of the Lactobacillus sp as gram positive or gram negative organism.

2. Spore staining technique was examined for the isolated strain as a spore forming or non spore forming organism.

3. Motility test were performed for the for the identification of the motility or non motility of the organism.

MICROSCOPIC OBSERVATION

• For the confirmation of the organism various Bio-chemical tests were performed.

1. IMViC test2. Catalase test3. Oxidase test4. Triple sugar iron test5. Sugar fermentation test6. Hydrogen per oxide test

BIO-CHEMICAL CHARACTERISTICS

PRODUCTION OF BACTERIOCIN

ANTI BACTERIAL ACTIVITY• Muller Hinton agar were prepared and sterilized.• After sterilization the medium were poured in to

a sterile Petri plates and allow to solidify.• In the sterile agar plates wells are cutted.• Using a sterile swab the different bacterial

cultures were swabbed on Muller Hinton agar plate.

• the crude bacteriocin supernatant were added 20µl,50µl,75µl,100µl respectively at 37°c for 24 hours.

• The result were observed and tabulated.

RESULT

• Lactobacillus culture was isolated and identified from the milk sample and it was confirmed by the microscopic observation and biochemical characteristics.

S. No Characteristic features Lactobacillus sp

MICROSCOPIC EXAMINATION

1. Gram’s Staining Gram Positive

2. Shape Rod

3. Spore staining Non-spore forming

4. Motility Non- motile

RESULT FOR MICROSCOPIC OBSERVATION

S. NO CHARACTERIZATION

RESULT

1. Indole Negative2. Methyl red Negative3 Voges Proskeaur Negative4. Citrate Negative5. Catalase Negative6. Oxidase Negative7. Triple sugar iron

testAlkaline Slant

8. Hydrogen per oxide test

Positive

BIO- CHEMICAL IDENTIFICATION RESULT

CARBOHYDRATE FERMENTATION TEST RESULT

PRODUCTION OF BACTERIOCIN

ANTIBACTERIAL ACTIVITY USING BACTERIOCINS.NO BACTERIAL CULTURES CONCENTRATION OF

BACTERIOCIN(µl)

ZONE OF INHIBITION(mm)

1. Bacillus subtilis 513

2. Staphylococcus aureus 711

19

3. Escherichia coli 30µl 3

4. Pseudomonas fluorescence

30µl50µl75µl

100µl

CONCLUSION• Thus the bacteriocin production using

Lactobacillus sp were highly identified and its antibacterial activity was justified by the zone of inhibition.