In catalase test, we add H2O2 to test the presence of catalase enzyme.If the bubbles do not appear, It confirms that it is a lactic acid bacteria.
But to test antimicrobial activity by bacteriocin, Catalase enzyme is used to eliminate the H2O2 which cause zone of inhibition against indicator organism.
Lactic acid bacteria (LAB) do not normally produce catalase, a hydrogen peroxide scavenging enzyme. The lack of catalase allows, in bacteria such a LAB, the accumulation of H2O2. Hydrogen peroxide, in these bacteria, is mainly produced in their primary, central, metabolic activities, due to the action of oxidases such as pyruvate oxidase, lactate oxidase, and NADH oxidases. Accumulation of H2O2 as a result of the activity of these oxidases and of the lack of catalase (that would degrade the produced H2O2) can exert an antimicrobial activity upon other microorganisms that one might mistake for bacteriocin activity. For that reason, when you test for bacteriocin-related antibacterial activity, you have to exclude the H2O2 activity by adding catalase.
The catalase test results for lactic acid bacteria are negative. But some species of this bacteria can produce H2O2. Often, aerobic species can produce H2O2.
- Badges
- Science topic
- Similar topics
- Phytochemistry
- Extracts