Petri Dish Lab

Staphylococcus epidermis produces the enzyme catalase. In the PEA Agar, a catalase test was performed which showed that the organism produced catalase. Staphylococcus epidermis is not a mannitol fermenter. Mannitol fermenting organisms grow on the Mannitol Salt Agar. The unknown organism is not a mannitol fermenter because it did not grow on the Mannitol Salt Agar.

This test was conducted utilizing aseptic technique. I first properly labeled the test tube and aseptically inoculated an MR-VP broth tube with unknown bacteria number 5 using a sterile inoculating loop. After 4 days of incubation, I added 4 drops of methyl red ph indicator to the tube. The contents of the test tube turned yellow in color. This indicates a negative test result because unknown bacteria 5 utilized the butanediol pathway instead of the mixed acid fermentation pathway.

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

Catalase activity test establishes whether the bacterium produces the enzyme catalase. The eosin methylene blue test or EMB, inhibits the growth of gram positive bacteria and tests whether or not gram negative bacteria can ferment lactose. Lactose fermentation testing is done to see if the bacterium is capable of fermenting sugar by testing for acid and gas production. These are the possible tests that are needed in order to identify unknown

1 “substrate” and another “ enzyme.” Instead of using the distilled water, this time you are going to use different pH buffer in the enzyme test tube. In the substrate tube, add 7 mL of distilled water, 0.3 mL of hydrogen peroxide, and 0.2 mL of guaiacol for a total volume of 7.5 mL. For the enzyme tube, instead of distilled water add the pH solution (3) and 1.5 mL of peroxidase which equals a total volume of 7.5 mL. Use the dH2O syringe for our pH solution. To clean the syringe, flush it by drawing 6 mL of distilled water.

To begin, one must test for monosaccharides. Glucose is necessary, and is needed to be placed into a test tube at a quantity of 5 mL. 3 mL of Benedict’s solution is then added. The test tube is then placed in a beaker of boiling water for five minutes or until the color changes. If the color changes, then it is known that monosaccharides are present in the solution. Next, one will test for starches.

Starch amylase testing was equally unsubstantial since the only amylase producing bacteria was ruled out after Gram staining. Unknown #10’s negative citrate test result was also unhelpful because E. coli is citrate negative and P. vulgaris is a variable citrate producer that can also be citrate negative. H2S production in the Kligler’s Iron Agar test ultimately proved that Unknown #10 was Proteus vulgaris. P. vulgaris is the only assigned bacteria that produces H2S, so when a black precipitate obscured the yellow butt of the Kligler’s Iron Agar slant, E. coli was ruled out. Not only did the H2S product confirmed that Unknown #10 was P. vulgaris, it confirmed P. vulgaris’ motility.

Rapid tests for detection of main Clostridial toxins Pérez-Etcheverry Diana* and Lorenzo-Ferreiro Carmen Laboratorio de Biotecnología del Instituto Polo Tecnológico de Pando - Facultad de Química, Universidad de la República. Canelones, Uruguay. *perezetcheverrydiana@gmail.com Abstract:

Enzymes speed up chemical reactions enabling more products to be formed within a shorter span of time. Enzymes are fragile and easily disrupted by heat or other mild treatment. Studying the effect of temperature and substrate concentration on enzyme concentration allows better understanding of optimum conditions which enzymes can function. An example of an enzyme catalyzed reaction is enzymatic hydrolysis of an artificial substrate, o-Nitrophenylgalactoside (ONPG) used in place of lactose. Upon hydrolysis by B-galactosidase, a yellow colored compound o-Nitrophenol (ONP) is formed.

Introduction In class, a series of experiments were performed that pertained to the enzyme known as catalase, which converts hydrogen peroxide into oxygen. Due to peroxide being toxic to the tissues of both plants and animals, both possess the enzyme catalase, which breaks into two non-toxic compounds: water and oxygen gas. Enzymes are proteins that react to certain substrates to create a product, and continue doing so afterwards. Methods and Materials To test reactions between catalase and hydrogen peroxide, groups of three to four people were formed.

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

This agar comprise of dextrose, lactose and sucrose, which acts as the carbohydrates sources. The medium osmotic balance is maintain by Sodium chloride The fermentation of the carbohydrate lead to acid production of yellow colour agar, detected by the pH indicator in the media, phenol red. Detection of hydrogen sulfide is through the indicator Ferric Ammonium citrate. A black colour will be seen in the medium from the hydrogen sulfide production from thiosuplhate due to FeS production. [9],

H20 + 2 O2 This experiment will use 1% catalase solution and 3% hydrogen peroxide solution, both diluted into water so the reaction slows down. Temperature will be controlled in this experiment to change the reaction speed of the enzyme and the substrate, this is what the experiment is looking at. The effect of the temperature will be determined by how much gas is released in two minutes, which will change the pressure inside the test tube and will be measured by a gas

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

Joshua Miller 12/18/17 Fermentation Lab report Introduction The term fermentation refers to the chemical breakdown of a substance by bacteria, yeasts, or other microorganisms, typically involving effervescence and the giving off of heat (wikipedia). Sugars are converted to ethyl alcohol when fermentation happens. In this experiment we determined if yeast cells undergo fermentation when placed in a closed flask with no oxygen. Glucose and yeast are mixed together in a closed flask and allowed to incubate for about one hour.