I was given unknown #76.
I performed the streak plating method with my unknown organisms. To perform this exercise I needed a TSA plate and labeled the bottom of it with my name, group number and organism. I also divided the bottom into three sections. After that, I sterilized my inoculating loop using the bunsen burner flame. After letting the loop cool, I reached into my unknown test tube with my loop and grabbed the organisms. After that I streaked the top 1/8th of the plate then sterilized the loop. After letting the loop cook I streaked the second section of the plate while crossing into the first section three times. After that, I sterilized the loop and did the same thing for the third section as I did in the second section.
Once my organisms grew, I looked for isolated colonies.
Once I distinguished my two different isolated colonies, I took a sterile loop and grabbed one and spread it on half of a new TSA plate. After sterilizing my loop again, I did the …show more content…
Since it was gram positive, I knew my organism had a thick peptidoglycan and no outer membrane. After finding out my organism B was gram positive, I did the catalase test on it. After adding the two drops of H202 and seeing bubbles, I ruled out Streptococcus lactis. My organism did have the catalase enzyme; meaning it was either Bacillus subtilis or Staphylococcus. To distinguish the two, I performed the simmons citrate test on them. Since the tube stayed green I confirmed that my organism was Staphylococcus. My organism B could not degrade citrate, so that meant my organism was not Bacillus subtilis. In conclusion, my unknown organisms were Staphylococcus and Enterobacter aerogenes.
Kidane, Amine, Dr. Microbiology Laboratory Manual. 8th ed. N.p.: McGraw-Hill Education, 2015.