Question

If the transformation is successful, blue colonies will appear on the agar plate. However, you notice that both white and blue color colonies are presented on the agar plate. Please provide at least two explanations for it and at least one solution to avoid the same problem from happening.

Answer 1

Answer: 1. Competent cells that are used for transformation are contaminated with other bacteria. This leads to the appearance of white colony on the agar plate.

2. Contamination during transformation procedure due to handling problem or surface or laminar flow is not sterile.

Problem is avoided by :

1. Autoclave all the items that are required in the experiment.

2. Sterile all the instruments used in the experiment.

3. Pour 2 petri with antibiotic and used one petri for streaking the competent cell and other petri for streaking the transformed cell. This will ensure that the competent cells contamination.

If bacteria growth is appear in competent cell petri plate it means they are contaminated and you need to revise the experiment.