ABSTRACT The purpose of the lab experiment was to identify an unknown bacteria culture using distinctive tests. The classification was accomplished by identifying the unknown based on its characteristics and morphology. A number of techniques were used to test the unknown. The unknown was a negative Gram-stain rod, tested negative for the oxidase text, and positive for the catalase test confirming its gram reaction and morphology. Other tests included Thioglycollate broth test, Nitrate reduction test, SIM (Sulfur-Indole-Motility) test, and MR-VP (Methyl Red-Voges-Proskauer) test and Lysine decarboxylase test. The results of the investigation suggested that unknown 10 is a sample of Enterobacter aerogenes. INTRODUCTION The experiment was centered on metabolic and biochemical testing procedures. Enterobacter aerogenes is a universal bacterium in the environment isolated naturally in soli, fresh water, vegetables, plants, dairy products, cosmetics, and human and animal feces. E. aerogenes can cause infection in many parts of the human body. It is often a cause of Lower-respiratory infections, including pneumonia. It may also cause urinary tract infection, soft tissue infection, endocarditis, septic arthritis, and infections of the skin and underlying tissues. If the bacteria reach the blood, it can lead to Sepsis. E. aerogenes is commonly a hospital acquired infection especially in patients in the intensive care unit or on mechanical ventilators. E. aerogenes more frequently affect new born and elderly (Fraser et al., 2013) MATERIALS AND METHODS Unknown bacteria were distributed to all of the students in microbiology lab by the T and my unknown specimen for the study was unknown number 10. Almost all of the techniques learned in the lab were used to aid in identifying the unknown. The course manual served as the basis for the procedures. The first method used was the quadrant streak plate; this was done to isolate the unknown 10 bacteria on two nutrient plates by the used of an inoculating loop, a Bunsen burner, two nutrient agar plates, an ENA, and a NA plate. Both plates were streaked and the ENA was incubated at a temperature of 37 degree Celsius, while the NA plate was incubated at a room temperature of approximately 25 degree Celsius for forty-eight hours. By the next lab period, bacterial growths were noted on the ENA plate, but not the NA plate. Growth on the ENA plate was then tested for a gram response following the steps of gram staining from the course manual using crystal violet, iodine, ethanol, and safranin to identify characteristics of the unknown. After observi