Prof. Dr. Sevgi ERTUĞRUL KARATAY

Prof. Dr. Sevgi ERTUĞRUL KARATAY

Biochemical Tests

Enzymatic Activity Tests-Lipase Activity Test Lipase enzyme is an enzyme that performs the

hydrolysis of ester bonds in lipids.

A microorganism with a lipase enzyme forms a zone of lipolysis in special media.

Lipolysis zone: Lipase (+)

If there is no lipolysis zone: Lipase activity is evaluated

as (-).

Enzymatic Activity Tests-Lipase Activity Test

E. coli

Geotrichum candidum

Pseudomonas fragi

Control

Biochemical Tests

Enzymatic Activity Tests-Caseinase Activity Test

The caseinase is an enzyme that performs the hydrolysis of casein molecules, also known as milk protein.

A microorganism with caseinase enzyme forms a zone of proteolysis in milk agar medium.

If proteolysis zone exists: Caseinase (+)

If there is no proteolysis zone: Caseinase (-).

Enzymatic Activity Tests-Cazeinase Activity Test

B

A C

Kontrol

Biochemical Tests

Enzymatic Activity Tests-Gelatinase Activity Test

Gelatinase is an enzyme that performs the hydrolysis of gelatin protein.

If microorganism having the gelatinase enzyme forms a gelatinase zone in the gelatin nutrient medium.

If there is liquefaction in the medium: Gelatinase (+)

If there is no liquefaction in the medium: It is evaluated as

gelatinase (-).

Enzymatic Activity Tests-Gelatinase Activity Test

In the gelatinase test, if the microorganisms placed on the slant agar gelatinase activity, liquefaction is

observed in the medium.

Biochemical Tests

Enzymatic Activity Tests-Hemolytic Activity Test

Hemolytic activity (hemolysin test) is a test for the

breakdown of red blood cells. There are three types of

bacteria according to hemolytic activity: Alpha, beta and

gamma.

Biochemical Tests

Enzymatic Activity Tests-Hemolytic Activity Test

Alpha hemolysis: No full zones are observed around the colonies;

Beta hemolysis: Red blood cells break down and large zones are observed.

Gamma hemolysis: No zone is observed. Indicates absence

of activity.