According to the series of test that my group ran for our unknown specimen, we had a match with the bacteria known as Alcaligenes Faecalis. This bacterium belongs to one of the major group of gram-negative bacteria (Phylum Proteobacteria). Alcaligenes Faecalis (Genus, species) is a rod shaped (bacillus), 0.5-1.2 x 1.0-3.0 µm, round with scalloped margin (colony configuration growth), motile (with one to nine peritrichous flagella), gram-negative, non-fermentative bacteria, obligate aerobic, having oxygen as the principal terminal electron acceptor in the electron transport chain (ETC). We consider we have a match with the species Alcaligenes Faecalis because of the following reasons: Fermentation tests performed (Durham sugars) were negative, which indicate that our bacteria use a different metabolic means for growth (non-fermentative gram-negative bacteria).
There was a strong odor similar to the smell of vinegar given off. After the solution was heated and the solid dissolved, 0.2 mL of hydrobromic acid was added to the test tube. The solution turned a bright yellow color after the hydrobromic acid was added. The solution was heated in a hot water bath for 5-10 minutes and then let cool. After heating, the
Biochemical tests are the tests used for the identification of bacterial species based on the differences in the biochemical activities of different bacteria. Bacterial physiology differs from one species to the other. These differences in carbohydrate metabolism, protein metabolism, fat metabolism, production of certain enzymes and ability to utilize a particular compound help them to be identified by the biochemical tests. Gram’s stain was originally devised by histologist Hans Christian Gram in 1884. Gram-positive bacteria stain purple, while Gram-negative bacteria stain pink when subjected to Gram staining.
Aseptic technique was initiated at the beginning of this experiment by cleaning the work surface with disinfected wipes. Personal protectives equipment was also worn. The material utilized in this experiment was: S. epidermidis culture broth, sterile cotton swab, streak plate, forceps in 70% alcohol, a lit tea light, and the three antibiotic disks (novobiocin, gentamicin, penicillin). The first step, I divided a plate into three quadrants and labelled them with the different antibiotic names. Using the lit tea light, like a bursen burner, I flamed the mouth of the S. epidermidis culture.
Being able to identify unknown microbes from systematic testing is what makes the field of microbiology so important, especially in infectious disease control. Using the testing procedure laid out by the microbiology field we are able to identify unknown bacteria present in our everyday lives, and along the way learn a lot about their characteristics that separate them from other types of bacteria. Being able to do this is vital in order for us to understand why microbes are present in certain places, how they are able to grow and what restricts their growth, that way they can be combatted if necessary. These techniques for determining unknowns are also important for isolating and testing infectious disease microbes in order to prevent spreading. Another important aspect of being able to identify unknown microbes is the
Then, tests are performed to determine if the products of aerobic and anaerobic respiration are present in the flasks. The citric acid cycle consists of a series of chemical reactions used by all aerobic organisms to release stored energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins into carbon dioxide and chemical energy in the form of ATP (Biology). The tests detect the presence of carbon dioxide and ethanol. Carbon dioxide should be present irrespective of the type of respiration taking place, but ethanol is present only if fermentation has occurred. Another factor that can indicate whether fermentation occurred or cellular respiration occurred is the amount of glucose utilized during incubation.
The student is to use studied tests to eliminate possible generas and to isolate the correct genus and identify it to the given unknown. This proves the diversity of microorganisms and their uniquely varying traits. The resulting data obtained in class will enhance students’ laboratory skills and knowledge regarding microbial laboratory. Introduction
The starch-iodide complex forms because of the transfer of charge between the starch and iodide ion and results in spacing between the energy levels. This allows the complex to absorb light at different wavelengths resulting in a dark blue colour (Travers et al., 2002). A blue colour would indicate a positive test while a yellow colour would show a negative test. The Benedict’s test is useful for reducing sugars.
The media used in this experiment was Trypticase nitrate broth. The reagents used (A and B) were sulfanilic acid and alpha-naphthylamine (respectively). Using aseptic technique, the bacterium (16A and 16B) were inoculated into labeled broth test tubes. The tubes were incubated for 48 hours at 37 degrees Celsius. When the incubation was complete 5 drops of reagent A and 5 drops of reagent B were added to each of the broths.
Uncontrolled Environmental conditions Atmospheric conditions The controlled variable Concentration of amylase was kept under control by measuring the amount of amylase used and also it was made sure the percentage of amylase used was 1%. The Amount of amylase/starch used were kept to 5cm3 at all times. Materials needed Beakers Bunsen burner Test tube Thermometer Stopwatch Test plate Glass rod Starch Amylase solution Water bath Iodine solution. Test tube holder Labels Marker Procedure First 5 test tubes were taken and labeled with numbers from 1 to
Staphylococcus epidermidis is the organism that was identified based on the tests that I had conducted. The tests that I used to identify this organism were the coagulase test and the catalase test. My bacterium was beta hemolytic as well. First, a gram stain had to be done to determine whether the organism was a gram positive organism or a gram negative organism. This determined which set of tests that had to be done. My bacterium turned out to be gram positive. When conducting these tests, I only had to do the coagulase test and the catalase test because when doing the catalase test, the reaction was that it had bubbled. If it did not bubble, or have a positive reaction, then I would not have had to do the coagulase test. Also, since my bacterium caused a positive catalase test, I only had to do the coagulase test and no other tests. This is because with staphylococcus organisms, these are the only tests
After experiment on microscope under oil immersion, I learned that my Unknown is gram positive. Under the lens, the bacteria appears in purple color. Its morphology is cocci arranged in cluster. However, during decolorizing process, I put too much alcohol to the crystal violet-iodine complex making the color overly removed. That led to the result of my gram positive has slightly redish
In test tube E, a colourless colour formed. It is because redox reaction occurred during the test. Idoine reduced into idoine ion ， which changre from brown to colourless. In test tube F, the iodine solution change from brown to purple . It is because the salt has a function of cofactor which will shorten the time for amylase to take to break down the