Which organism among the following is catalase negative?

Which organism among the following is catalase negative?

• A. Bacillus
• B. Corynebacterium
• C. Leuconostoc
• D. Listeria

Answer: (C)

Catalase status helps distinguish organisms based on whether they produce the enzyme that breaks down hydrogen peroxide. When a drop of hydrogen peroxide is added to a catalase-positive organism, rapid bubbling occurs due to oxygen release; catalase-negative organisms show no bubbles. Among the options, Bacillus, Corynebacterium, and Listeria are typically catalase-positive, so they would produce bubbles. Leuconostoc is a lactic acid bacterium that does not produce catalase, so it does not bubble with hydrogen peroxide. This makes Leuconostoc catalase negative.

Catalase status helps distinguish organisms based on whether they produce the enzyme that breaks down hydrogen peroxide. When a drop of hydrogen peroxide is added to a catalase-positive organism, rapid bubbling occurs due to oxygen release; catalase-negative organisms show no bubbles. Among the options, Bacillus, Corynebacterium, and Listeria are typically catalase-positive, so they would produce bubbles. Leuconostoc is a lactic acid bacterium that does not produce catalase, so it does not bubble with hydrogen peroxide. This makes Leuconostoc catalase negative.