aeruginosaappeared light brown and had a smooth colony margin. On the sodium azide plate only E. faecalisand S. aureusgrew. E. faecalis had regular and smooth growth, while S. aureus had small colonies and so the morphology could not be differentiated. It could be concluded that MacConkey only allows gram negative bacteria to grow since it supported E.coliand P. aeruginosa. And sodium azide only supports gram positive bacteria. In the culture technique, I was able to isolate a single bacterial colony. Additionally, there wasno evidence of contamination on my plate.QuestionsThe difference between sterilized media is that it is autoclaved and therefore it can support bacterial growth. Sterilized media is put under immense pressure and temperature to denature the proteins of the bacteria. Non-sterilized media has bacterial growth since it has not undergone protein denaturation. The growth of the four strains of bacteria did not grow in the synthetic medium. However ,they did grow in the complex media. This indicates that the synthetic media did not have the proper nutrients to allow bacteria to grow.In the sodium azide plate only E. faecalis and S. Aureus grew. This is because sodium azide inhibits the cytochromes oxidase in gram negative bacteria. However, it does not affect gram positive bacteria. In the MacConkey plate the bile salts destroy gram positive bacteria. Gram negative cells such as E.coliand P. aeruginosaare not destroyed because they have a double membrane system that protects them.Finally, in the pure culture technique I was able to achieve a singly colony isolation and confirmed a pure culture. There was also no contamination and no sources of error thankfully.
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