Page 112 - MNUmicrobiology practical 2025

General Microbiology & Immunology (PM 401) second level Semester 4 2024/2025

3- Catalase Test
• Purpose: Production of catalase.

• Media: TSA

• Reagents/indicators: 3% Hydrogen Peroxide (H 2O 2)

• Mechanism/reactions: Catalase converts hydrogen peroxide, a by-product of oxidative

respiration, to oxygen and water. Anaerobes and aerotolerant anaerobes lack this

enzyme.

• Directions: Apply several drops of 3% (H 2O 2)to growth from a TSA plate.

4- Oxidase Test
• Purpose: The oxidase test identifies organisms that produce the enzyme cytochrome

oxidase

• Media: Use growth from a TSA plate or slant

• Reagents/indicators: Oxidase reagent 1% N,N,N'N' tetramethyl-p-phenylenediamine

General Microbiology & Immunology (PM 401) Practical note Page 101