Catalase Lab Report

An unknown bacterium was handed out by Dr. Honer. The appropriate tests were prepared and applied. The first procedure that was done was the gram stain. Under a microscope, if the gram stain is purple, the bacterium is gram positive, if the stain is red, it is gram negative. The next test was the fermentation tests for glucose, sucrose and

This experiment was centered on metabolic and biochemical testing procedures. The rationale of performing these tests was to distinguish six different microbes from one another and to compare how their metabolic and biochemical processes differ from species to species to determine the unknown sample.

Fermentation is a metabolic pathway that produce ATP molecules under anaerobic conditions (only undergoes glycolysis), NAD+ is used directly in glycolysis to form ATP molecules, which is not as efficient as cellular respiration because only 2ATP molecules are formed during the glycolysis. One type of fermentation is alcohol fermentation, it produces pyruvate molecules made by glycolysis and the yeast will break it down to give off carbon dioxide, the reactant is glucose and the byproducts are ethanol and carbon dioxide. In this lab, the purpose is to measure whether the changes of

The human body is an incredible system that is capable of working a multitude of diverse functions. Without the help of the many different protein molecules, the human body would not be able to function properly. One major group of proteins called enzymes are mandatory for essential life. These proteins are constantly at work assembling molecules, metabolizing energy, and fighting off infections. An enzyme is a macromolecule that acts as a catalyst that speeds up a chemical reaction without being consumed by the reaction. Without these proteins, these reactions would take place too slowly to keep us alive. Essential parts in your body like vitamins and minerals cannot do any work without

The first result of importance was the result of the Gram stain. The observations of the unknown bacteria from the slant culture after Gram staining showed that the unknown bacteria were Gram negative bacilli (Image 1). After determining the unknown bacteria was Gram negative, an oxidase test was conducted on a sample from the slant culture. The cotton swap with the sample of bacteria did not change color when the oxidase reagent was applied, thus providing a negative result. With a negative oxidase test, further tests were conducted to determine various characteristics of the unknown bacteria. A MR-VP broth was inoculated with a sample from a slant culture of unknown bacteria. After incubation, the methyl red reagent was added to the broth, and the broth turned red, providing a positive result (Image 2). An EMB agar streak plate was inoculated with a sample from a slant culture of the unknown bacteria, and after incubation, growth was found on the plate, providing a positive result (Image 3). A Citrate agar slant was inoculated, and after incubation, growth was found on the media, providing a positive result (Image 4). A Urea agar slant was inoculated, and after incubation, the agar had changed from a peach color to a bright pink color, providing a positive result (Image 5). Using the flowchart (Figure 1) developed from the Table of Expected Results, the lab partners started at the oxidase test. Given the negative result of the oxidase test, the flowchart is

I began by running the starch test, which tests for the presence of starch hydrolyzing enzymes. After doing a one-line inoculation of the organism, the plate had to be incubated. Once I received an appropriate amount of growth I added the reagent iodine. The iodine turned the plate purple, formed no clear zone, and lifted the organism off of the plate, which revealed that the starch was not degraded and the enzyme was not present. The organism being lifted off the plate is unique to the bacteria Corynebacterium xerosis indicating that it was my gram positive rod. For reassurance, I ran the Phenol Red Glucose test, which tests if the organism contains various enzymes that determine if the bacteria can ferment glucose. After incubation, the broth turned orange, but this did not provide a clear positive or negative result so I ran the Nitrate Broth Reduction test. The Nitrate Broth Reduction test detects if the organism utilizes nitrate. After incubation for forty-eight hours I added Nitrate A and Nitrate B indicators. However, there was no color change indicating that the test was inconclusive. Since the test was inconclusive, I proceeded to the following step, which included adding a small amount of zinc to the broth, and this turned the broth a red color. The red color indicated that

This test is used to detect if the bacteria contains any deoxyribonuclease activity. Because no color change was observed from blue to clear my unknown bacteria displayed a negative result.

Why or why not? Different types of bacteria are rubbed on each side of a petri dish. If there is more bacteria put on one side that side is going to grow more. Just because they are in the same petri dish doesn’t mean that they

To perform this test, a tube of broth rich with glucose is acquired. In this tube is phenol red, a pH indicator. Initially, the tube appeared pink in color, indicating a normal pH level. Next, a sample of unknown #44 is introduced into this medium using the aseptic technique, and this is allowed to sit for several days. If the organism is able to ferment glucose, the pH in the medium would decrease and cause the phenol red to exhibit a yellow color. In addition to the straw color, gas can also be produced and trapped inside the Durham tube placed in the medium. This production of acid and gas is a direct result of the fermentation of glucose, as seen with unknown

Bacteria groups or species can be differentiated by the fermentation patterns. The end-product of carbohydrate fermentation is an acid or acid with gas production and is dependent on the organism involved in the fermentation process. The carbohydrate fermentation tests detect if an organism is able to utilize glucose, lactose and sucrose. Phenol red is used as a pH indicator because it can indicate a change in pH when acid products are formed. Bacteria can utilize certain sugars resulting in an alkaline by-product which changes the color of the carbohydrate broth from red to yellow. Bubbles trapped within the Durham tube indicate the production of gas. The Phenol red carbohydrate fermentation tests determine that my organism E. coli can utilize glucose, lactose and sometimes sucrose but can only produce gas in glucose and lactose. (Phenol red carbohydrate fermentation lab

The purpose of this experiment was to record catalase enzyme activity with different temperatures and substrate concentrations. It was hypothesized that, until all active sites were bound, as the substrate concentration increased, the reaction rate would increase. The first experiment consisted of five different substrate concentrations, 0.8%, 0.4%, 0.2%, 0.1%, and 0% H2O2. The second experiment was completed using 0.8% substrate concentration and four different temperatures of enzymes ranging from cold to boiled. It was hypothesized that as the temperature increased, the reaction rate would increase. This would occur until the enzyme was denatured. The results from the two experiments show that the more substrate concentration,

Therefore, the purpose of this test to identify bacteria based on these features. As a result, we had white, slime, a little shiny colonies that was shaped as almost a flower. In addition, we were able to know if the bacteria was positive or negative for the catalase reaction. Catalase reaction is done by adding hydrogen peroxide—H2O2.

The Christensen’s urea agar slant utilized a phenol red indicator that changed colors to pink when pH conditions became basic. If urease were present, it would hydrolyze urea to ammonia and CO2 (17). Because no color change was observed, the organism was negative for urease. However, the organism was positive for catalase, which was indicated by the formation of bubbles following the addition of H2O2 to the TSA slant. This showed the breakdown of H2O2 into O2 by catalase (10).

Catalase Experiment In many cases, the body needs a way to break down proteins, enzymes, and even poisons. In this case our main goal within this experiment was to break down hydrogen peroxide. When you add an enzyme called, catalase, and it will break hydrogen peroxide down into water and oxygen gas. As the lab went on we were trying to test the activity between catalase and hydrogen peroxide (the action of the enzyme in the environment).

This experiment is designed to analyze how the enzyme catalase activity is affected by the pH levels. The experiment has also been designed to outline all of the directions and the ways by which the observation can be made clearly and accurately. Yeast, will be used as the enzyme and hydrogen peroxide will be used as a substrate. This experiment will be used to determine the effects of the concentration of the hydrogen peroxide versus the rate of reaction of the enzyme catalase.