Test Reagents Used in Microbiology Laboratory
1. For Catalase test
Catalase Reagent (3% H2O2)
Hydrogen peroxide 3 ml
Distilled Water 97 ml
Preparation: To 97 ml of D/W, 3 ml of hydrogen peroxide is added and mixed well.
2. For Oxidase Test
Oxidase Reagent (impregnated in Whatman’s No. 1 filter paper)Tetramethyl p-phenylene diamine dihydrochloride 1 gm
Distilled Water 100 ml
Preparation: This reagent solution is made by dissolving 1 gm of TPD in 100 ml D/W. To that solution strips of Whatman’s No. 1 filter paper are soaked and drained for about 30 seconds. Then these strips are freeze dried and stored in a dark bottle tightly, sealed with a screw cap.
3. For Indole Test
Kovac’s Indole ReagentIsoamyl alcohol 30 ml
p- dimethyl amino-benzaldehyde 2.0 g
Hydrochloric acid 10 ml
Preparation: In 30 ml of isoamylalcohol, 2 g of p-dimethyl aminobenzaldehyde is dissolved and transferred to a clean brown bottle. Then to that, 10 ml of conc. HCl is added and mixed well.
4. For Methyl Red Test
Methyl Red SolutionMethyl red 0.05 g
Ethyl alcohol (absolute) 28 ml
Distilled Water 22 ml
Preparation: To 28 ml ethanol, 0.05 gm of methyl red is dissolved and transferred to a clean brown bottle. Then 22 ml D/W is added to that bottle and mixed well.
5. Voges-Proskauer Test (Barritt's Reagent)
Solution Aα-Napthol 5.0 g
Ethyl alcohol (absolute) 100 ml
Preparation: To 25 ml D/W, 5 g of α-Napthol is dissolved and transferred into a clean brown bottle. Then the final volume is made 100 ml by adding D/W.
Solution B
Potassium hydroxide 40.0 g
Distilled Water 1000 ml
Preparation: To 25 ml D/W, 40 gm of KOH is dissolved and transferred into a clean brown bottle. Then the final volume is made 100 ml by adding D/W.
6. Bile Salt Solution
Commercially available sodium deoxycholate 10 g
Distilled Water 100 ml
Preparation: A 10% solution of sodium deoxycholate is prepared by adding 10 gm sodium deoxycholate powder in 100 ml distilled water and transferred in a clean brown bottle and is autoclaved.