INTRODUCTION
There are many reasons for knowing the identity of microorganisms. The reasons range from the knowing the causative agent of a disease in a patient, so as to know how it can be treated, to knowing the correct microorganism to be used for making certain foods or antibiotics. This study was done by applying all the methods that have been learned so far in the microbiology laboratory class for the identification of an unknown bacterium.
MEDIA LIST
 Unknown Bacterium #5
 Mannitol Salt Agar Plate
 DNA Agar Plate
 Blood Agar Plate
RESULTS/ DATA
The Unknown #5 had the following morphology after Gram staining and observed under a brightfiled microscope: purple color, spherical shape and clustered like grape. After determining that it was a Gram positive staphylococcus, it was inoculated on a MSA plate, Blood Agar, DNA agar and Catalase test was also performed to help figure out the staphylococcus type. The Table below lists all of the biochemical tests, their purpose and results.
TEST PURPOSE REAGENTS OBSERVATIONS RESULTS
Gram Stain To determine the Gram reaction of the bacterium Crystal violet, Iodine, Alcohol, Safranin Purple grape cluster arrangement cocci Gram
Positive coccus
Mannitol
Salt Agar To determine the if the bacterium can tolerate high saline levels and grow

If the bacterium can ferment mannitol

None There was a full growth and the mannitol turned to yellow (acidic)

Positive
Blood Agar To determine if the bacterium can hemolysis blood
None Metallic gray, Creamy – golden color ß-hemolysis Positive
DNA Agar To determine if bacterium has DNase and can hydrolyze DNA
None Clearing around the bacterial growth Positive
Catalase
Test To determine the presence of the enzyme catalase (converts H2O2 to H2O and O2)
Hydrogen peroxide

Immediate bubbles

Positive

DISCUSSION/CONCLUSION
After