PHYSIOLOGICAL TESTS (LAB)
1) Catalase Production, Nutrient Agar Slant
Capability to break down peroxide to water & oxygen
Enzyme: Catalase
Reagent: Hydrogen peroxide several drops on culture
Results: After adding several drops of hydrogen peroxide, if it bubbles, organism is
catalase-positive
2) Fluid Thioglycollate Media (FTM)
Determines oxygen requirements
•Enzyme: N/A
•Reagent: N/A
•Results:
Aerobic - growth on top;
Anaerobic - growth on bottom;
Facultative - growth throughout;
Microaerophilic - growth just below the top
Aerotolerant - growth throughout (can tolerant oxygen)
3) Gelatin Deep
If organism able to digest gelatin
•Enzyme: Gelatinase
•Reagent: Refrigerate for 30 minutes before reading
•Results: If gelatin liquefied, organisms positive for producing gelatinase. Can hydrolyze
gelatin
4) Glucose, Lactose & Mannitol Fermentation Broth
Determines if organism can ferment glucose, lactose & mannitol. If so, produces acid &
gas may be produced
•Enzyme: N/A
•Reagent: N/A
•Results: If broth turns yellow, produces acid. If broth has a bubble on inverted tube,
organism produces gas as well
5) Litmus Milk
Acid - production;
Alkaline - lactalbumin digest forming ammonia;
Reduction - reductase removes oxygen from litmus;
Coagulation - casein to paracasein by rennin;
Peptonization - to digestion of casein;
•Enzyme:
Proteolytic - for peptonization
Reductase - for litmus reduction
Rennin - for coagulation
•Reagent: N/A
•Results:
Pink - Acid: fermentation of glucose
1) Catalase Production, Nutrient Agar Slant
Capability to break down peroxide to water & oxygen
Enzyme: Catalase
Reagent: Hydrogen peroxide several drops on culture
Results: After adding several drops of hydrogen peroxide, if it bubbles, organism is
catalase-positive
2) Fluid Thioglycollate Media (FTM)
Determines oxygen requirements
•Enzyme: N/A
•Reagent: N/A
•Results:
Aerobic - growth on top;
Anaerobic - growth on bottom;
Facultative - growth throughout;
Microaerophilic - growth just below the top
Aerotolerant - growth throughout (can tolerant oxygen)
3) Gelatin Deep
If organism able to digest gelatin
•Enzyme: Gelatinase
•Reagent: Refrigerate for 30 minutes before reading
•Results: If gelatin liquefied, organisms positive for producing gelatinase. Can hydrolyze
gelatin
4) Glucose, Lactose & Mannitol Fermentation Broth
Determines if organism can ferment glucose, lactose & mannitol. If so, produces acid &
gas may be produced
•Enzyme: N/A
•Reagent: N/A
•Results: If broth turns yellow, produces acid. If broth has a bubble on inverted tube,
organism produces gas as well
5) Litmus Milk
Acid - production;
Alkaline - lactalbumin digest forming ammonia;
Reduction - reductase removes oxygen from litmus;
Coagulation - casein to paracasein by rennin;
Peptonization - to digestion of casein;
•Enzyme:
Proteolytic - for peptonization
Reductase - for litmus reduction
Rennin - for coagulation
•Reagent: N/A
•Results:
Pink - Acid: fermentation of glucose
