1. GELATIN HYDROLYSIS TEST Purpose :
Determination of the ability of the organisms to digest (hydrolyse) gelatin, as a sole source of protein by activity of the gelatinase enzyme.
Materials :
1. Aeromonas hydrophila on BA.
2. Escherichia coli on BA.

2. GELATIN HYDROLYSIS TEST Media & Reagents :
1. Gelatin agar plates.
2. Acid mercuric chloride solution
Method :
1. Inoculate by cross streaking of 1 & on each of gelatin plates.
2. Incubate at 370C for 24 hrs.

3. GELATIN HYDROLYSIS TEST Interpretation :
Before reading, flood the cultures with acid mercuric chloride, leaving for 5-10 minutes.
Positive : clear zone around colony.
Negative : no clear zone around colony.

4. GELATIN HYDROLYSIS TEST
Positive : clear zone around colony.
Negative : no clear zone around colony.

5. STARCH HYDROLYSIS TEST Purpose :
To determine the ability of the organism to produce amylase enzyme which digests or hydrolyses starch.
Materials :
1. Bacillus subtilis on BA.
2. Escherichia coli on BA.

6. STARCH HYDROLYSIS TEST
Media & Reagents :
1. Two starch agar plates.
2. Lugol’s iodine solution.
Method :
1. Inoculate 1 & 2 on each of starch agar plate.
2. Incubate at 370C for 24 hrs.

7. STARCH HYDROLYSIS TEST Interpretation :
Flood the cultures with Lugol’s solution, and remain for 5-10 minutes.
Positive : clear zone around colonies.
Negative : no clear zone around colonies.
Remark : Some orgamisms, produce weak reaction, clear zone present under colonies.

8. STARCH HYDROLYSIS TEST
Positive : clear zone around colonies.
Negative : no clear zone around colonies.

9. CASEIN DIGESTION TEST Purpose : Materials :
To determine the ability of organisms to produce caseinase (proteinase) enzyme which digest casein.
Materials :
1. Aeromonas hydrophila on BA.
2. Escherichia coli on BA.

10. CASEIN DIGESTION TEST Media & Reagents : Method :
Two casein agar plates.
Method :
1. Spot inoculation of 1 & 2 on each of casein agar plates.
2. Incubate at 370C for 24 hrs.

11. CASEIN DIGESTION TEST Interpretation :
Positive : clear zone around colonies.
Negative : no clear zone around colonies.

12. Lecithinase & Lipase activities Purpose :
LECITHOVITELLIN REACTION (LV)
Lecithinase & Lipase activities
Purpose :
To determine the ability of the organisms to produce lecithinase or/and lipase. The enzymes are demonstrated by cultivation on egg yolk agar.

13. Lecithinase & Lipase activities
LV REACTION
Lecithinase & Lipase activities
Materials :
1. Bacillus cereus on BA.
2. Aeromonas hydrophila on BA.
3. Bacillus subtilis on BA.
Media & Reagents :
Two egg yolk agar plates.

14. LV REACTION
Lecithinase & Lipase activities Method : Spot inoculate 1, 2 & 3 on each of L-V agar plate Incubate at 370C for 24 hrs. Reaction : Zone of opalescent around colony indicated lecithinase activity against lecithovitellin in egg yolk and precipitation around colony indicated lipase activity.