A streak plate method will be used to obtain a pure culture of a Gram positive coccus genus of bacteria. Several biochemical tests will be performed to aid in the identification of this unknown bacterium.
Madhab Sapkota Abstract In this experiment an unknown gram-negative sample was obtained randomly to identify the possible microorganisms. Using comparative analysis several biochemical tests were performed to determine which bacterium out of the six potential unknowns was given.
In order to determine the microorganism characteristics the sample was first isolated using a t-streak and the colonies were gram stained to reveal its shape and morphology and then inoculated into several sequences of media corresponding with the proper biochemical test.
After allowing the corresponding time for each biochemical test, data was collected to determine the unknown bacteria.
The broth culture in this experiment was determined as Escherichia coli. Introduction All organisms are divided into three domains; bacteria, archaea, and eukarya. The organisms making up domain Bacteria and domain Archaea are all prokaryotes. Although bacteria and archaea look the same, archaea is more closely related to eukarya Madigan et.
The ability to adapt to a broad range of habitats helps to explain why prokaryotes are the most abundant organism on earth. The main characteristics of a prokaryote include, no nucleus, circular DNA, and no membrane bound organelles. A key feature of nearly all prokaryotic cells is the cell wall, which maintains cell shape, and provides physical protection.
Most bacterial cell walls contain peptidoglycan, a network of modified-sugar polymers cross-linked by short polypeptides. All known pathogenic bacteria fall under prokaryotes, but not all bacteria are pathogenic Madigan et.
Using a differential staining technique bacteria can be divided into two groups; gram positive or gram negative. The gram-positive bacteria have thick cell wall made of peptidoglycan. Gram-negative bacteria have thinner layer of peptidoglycan, and are structurally more complex, with an outer membrane that contains lipopolysaccharides.
Gram staining is a valuable tool to determine whether an unknown bacterium is gram negative or gram positive. Samples are first stained with crystal dye and iodine, then rinse in alcohol, and finally counterstain with safranin.
In gram-positive bacteria the crystal violet adheres to the peptidoglycan layer staining it purple. In gram-negative the crystal violet is easily removed due to the thinner layer of peptidoglycan making the cell appear pink or red.
The domain bacteria is very diverse, making it impossible to identify it without the use of staining and biochemical tests. Biochemical tests can test for a variety of characteristics such as shape, morphology, pH, etc. Tests such as Methyl Red and Voges- Proskauer check for glucose fermentation.
The Citrate Test is a nutrient utilization test that determines whether a bacterium produces the enzyme citrate- permease to be utilized as its sole source of carbon. Urease test is used to indicate if a bacterium can hydrolyze the intracellular enzyme urea.
The Gelatinase test indicates whether or not a bacterium contains this exoenzyme which hydrolyzes the proteins and allows the gelatin to be converted into solid when is chilled. SIM gives three test results; Sulfur reduction, which determines whether a bacterium can use enzymes to reduce sulfur to hydrogen sulfide, Indole production used to determine if the bacteria can hydrolyze tryptophan to pyruvate, ammonia, and motility when in the semisolid media a motile bacteria can diverge from the stab line.
TSIA is designed to differentiate bacteria with reference to glucose fermentation, lactose fermentation, sucrose fermentation, and sulfur reduction Leboffe Materials and Method To prevent errors in any procedure personal protective and equipment aseptic technique was strictly used.
These techniques included sterilizing the loop on the Bunsen burner between inoculations and flaming the opening of the test tube before inserting in the loop with the bacteria. The plate was incubated for 24 hours in a in a 37 degree Celsius room and then transferred to a cold room 4degree Celsius room.
After incubation, a gram stain was performed on the isolated single colonies to determine if the unknown microorganism was indeed gram negative. First, the organism was smeared onto a slide with a drop of distilled water.
The smear was allowed to air dry and heat fixed right after to provide bacteria to stick onto the slide. Staining started with crystal violet, which is used to flood the slide completely for a minute and once again rinsed for about 10 seconds with DI water.
The slide was blotted dry with bibulous paper and was observed using the microscope under x oil immersion.Microbiology Unknown Lab Report. For Later. save.
Embed. Share. Print. Search. Related titles. Identification of Proteus Vulgaris From an Unknown Sample. Example of Bacteria Sample Testing Lab Report.
Micro Unknown Lab Report. Classification of Various Bacteria through Observations of Growth on Various Media Types.5/5(1). MICROBIOLOGY UNKNOWN LAB REPORT by Cheryl A. Glaeser Enterobacter aerogenes and Enterococcus faecalis INTRODUCTION: Bacteria serve many different roles in people’s lives today.
It is important to identify bacteria and differentiate pathogenic and non-pathogenic organisms. The first test performed on the gram positive bacteria was the Nitrate Test which turned red after adding reagents giving a positive result meaning the bacteria reduced nitrate into nitrite or something further.
Unknown Rport on Bacillus cereus Identifying the Unknown Bacteria: Bacillus cereus Brittany Moy Coastline Community College Abstract Bacillus cereus is a Gram-positive, facultative aerobic, spore-forming, rod-shaped bacterium that is widely distributed among the environment.
Bacillus cereus is a Gram-positive, facultative aerobic, spore-forming, rod-shaped bacterium that is widely distributed among the environment. Introduction The reason for identification of unknown bacteria was to help students recognize different bacteria through different biochemical tests and characteristics.
Urease Test- Principle, Media, Procedure and Result. The urease test is used to determine the ability of an organism to split urea, through the production of the enzyme urease.