Question

If you suspected that your unknown bacterium is either Pseudomonas or Proteus, what test could you use to differentiate between the two? O Citrate O Urease Indole O Oxidase O Catalase

Answer 1

Solution:

Correct answer-Option B : Urease

• Proteus is gram negative saprophytic bacteria .It can hydrolyze the urea and convert it into ammonia and used in confirmatory test for urease enzyme presence in bacteria. Pseudomonas is gram negative bacteria ,it does not posses the urease enzyme, thus can not hydrolyze the urea.

-To differentiating between the Pseudomonas and Proteus,We can take two testubes containing the pH indicator -Phenol red and urea in it.

On dropping the sample containing the bacteria. Test tube containing the Proteus will change the colour from yellow to pink ,as it will hydrolyze the urea .Ammonia is a weak base,it changes the colour of phenol red ,from yellow to pink.While Pseudomonas does not have urease enzyme , so sample containing the Pseudomonas will not change the colour of solution.

Hope this helps
Happy learning!!