Table 6 shows the results of the biochemical tests. The isolate can obtain its energy by means of aerobic respiration but not fermentation. In the Oxidation-Fermentation test, a yellow color change was produced only under both aerobic conditions, indicating that the EI can oxidize glucose to produce acidic products. In addition to glucose, the EI can also utilize lactose and sucrose, and this deduction is based on the fact that the color of the test medium broth changed to yellow in all three Phenol Red Broth tests. These results are further supported by the results of the Triple Sugar Iron Agar test. Although the EI does perform fermentation of these three carbohydrates, it appears that this bacterium cannot perform mixed acid fermentation nor 2,3-butanediol fermentation due to the lack of color change in Methyl Red and Vogues-Proskauer …show more content…
The isolate possesses some enzymes required for hydrolytic reactions. Hydrolytic enzymes found to be secreted from the bacterium, are -amylase, casein, and PYRase. In the starch hydrolysis and casein tests, there was a zone of clearing around the bacterium, which was indicative of the secreted enzymes necessary to break down starch and casein. In the PYR test, the presence of PYRase was detected by a color change to red on the PYR disc after the addition of the PYR reagent (p-dimethylaminocinnamaldehyde). Hydrolytic enzymes for which the EI tested negative were urease, gelatinase, and DNAse. In the Urea Hydrolysis test, it was observed that the urea broth did not have a color change, indicating that there was no urease secreted to break down urea in the broth. Similarly, there was no gelatinase present to break down gelatin in the Gelatin Hydrolysis test, so the nutrient gelatin remained solid. It was concluded that the EI does not possess DNase because there was no clearing zone around the bacteria, indicating that DNA had not been
In the lab, Inhibiting the Action of Catechol Oxidase we had to investigate what type of enzyme inhibition occurs when an inhibitor is added. Catechol oxidase is an enzyme in plants that creates benzoquinone.Benzoquinone is a substance that is toxic to bacteria. It is brown and is the reason fruit turns brown. Now, there are two types of inhibitors, the competitive inhibitor and non-competitive inhibitor. For an enzyme reaction to occur a substrate has to bind or fit into the active site of the enzyme. In competitive inhibition there is a substrate and an inhibitor present, both compete to bind to the active site. If the competitive inhibitor binds to the active site it stops the reaction. A noncompetitive inhibitor binds to another region
Compress the safety bulb, hold it firmly against the end of the pipette. Then release the bulb and allow it to draw the liquid into the pipette.
After 5 days of growth each slant was tested using the gram staining technique to confirm the complete isolation of the bacteria. Both isolations were completely successful. Then each sample of bacteria was subjected to a series of tests for identification.
Streak plate technique was used to isolate pure culture for each bacteria (2). The Gram stain was used to determine Gram reaction and morphology of each bacteria (2) Selective and differential media such as, salt agar, MacConkey agar and blood agar were used for bacterial identification (2). Gelatin deeps were inoculated to detect production of gelatinase (2). Starch Agar plate were inoculated to detect amylase (2). Ocular reticle used to determine bacteria size (2). Motility deeps were inoculated to detect motility on bacteria (2). Thioglycollate broth used to determine oxygen requirements (2). Carbohydrate fermentation
The purpose of this study is to identify an unknown bacterium from a mixed culture, by conducting different biochemical tests. Bacteria are an integral part of our ecosystem. They can be found anywhere and identifying them becomes crucial to understanding their characteristics and their effects on other living things, especially humans. Biochemical testing helps us identify the microorganism present with great accuracy. The tests used in this experiment are rudimentary but are fundamental starting points for tests used in medical labs and helps students attain a better understanding of how tests are conducted in a real lab setting. The first step in this process is to use gram-staining technique to narrow down the unknown bacteria into one of the two big domains; gram-negative and gram-positive. Once the gram type is identified, biochemical tests are conducted to narrow down the specific bacterial species. These biochemical tests are process of elimination that relies on the bacteria’s ability to breakdown certain kinds of food sources, their respiratory abilities and other biochemical conditions found in nature.
The purpose of this laboratory is to learn about cultural, morphological, and biochemical characteristics that are used in identifying bacterial isolates. Besides identifying the unknown culture, students also gain an understanding of the process of identification and the techniques and theory behind the process. Experiments such as gram stain, negative stain, endospore and other important tests in identifying unknown bacteria are performed. Various chemical tests were done and the results were carefully determined to identify the unknown bacteria. First session of lab started of by the selection of an unknown bacterium then inoculations of 2 tryptic soy gar (TSA) slants, 1 nutrient broth (TSB), 1 nutrient gelatin deep, 1 motility
The bacterium’s colonies on trypticase soy agar had an irregular shape, yellow pigment, umbonate elevation, and entire margin. Through Gram staining, I microscopically examined that the bacterium was Gram positive, rod shaped, and arranged in chains. There was presence of bubbles after testing for catalase, therefore it was a catalase positive. The bacterium was an Endospore positive because after a close examination under a microscope, I observed that it had Subterminal endospore as the its position. The Acid from mannitol test resulted as positive because the phenol mannitol red broth became yellow orange. Finally, the V-P test was negative because the media turned yellow. Overall, these results means that the unknown bacteria were Bacillus
Yersinia pestis is a zoonosis disease categorized in the family enterobacteriaceae. It is a non-spore forming, gram-negative coccobacilli that, when grown on agar, forms pin-point white/translucent colonies. Defining qualities of the Y. pestis are it’s bipolar staining, it’s negative test results for lactose fermentation, urease, and indole production, and positive testing for catalase. This pleomorphic bacterium is facultatively aerobic with an optimal growth temperature at 28 degrees Celsius. At temperatures above 37 degrees Celsius, it appears the Y. pestis is non-motile, but at temperatures less than 30 degrees Ce...
The purpose of this project was to identify unknown bacteria species from a mixed culture. The two unknown species were initially plated onto Tryptic Soy Agar (TSA), Eosin Methylene Blue (EMB), Mannitol Salt Agar (MSA), and blood agar plates to distinguish between the two different bacteria using colony size, color, shape, and growth characteristics. By identifying and inoculating the differing types of colonies, the two unknown bacteria were purified and able to be tested
Identifying microorganisms can provide information on diagnosing diseases and discovering the most beneficial treatment possible. The purpose of this assignment was to identify an unknown microorganism using biochemical tests and various methods that were learned in my microbiology laboratory classes. In this paper, I will discuss the processes of how I came to identify my unknown microorganism.
Talaro , K., & Chess, B. (2012). Foundations in microbiology. (8th ed., pp. 563-564). New York, NY:
In this experiment the enzyme peroxidase and the substrate hydrogen peroxide were not mixed initially, instead they were both placed in separate tubes and were incubated at a specific temperature, to prevent hydrogen peroxide from undergoing any reaction with peroxidase until they both acquire the required temperature.
This was narrowed down to Table 17.1 because the EI is a strict aerobe. Table 17.1 was viewed and it contained only six genera. Within the table there were twelve characteristics the genera were tested for, but only four of those tests were done on the EI. Those four tests were the motility test, the catalase test production of acid from carbohydrates, and cell arrangement (Table 2). The catalase test was positive for all genera, but the motility test was only positive for Marinococcus and Planococcus (Table 2). This difference helped to make the decision that the EI was not one of these two genera. Deinococcus was ruled out based on its cells predominantly arranging in pairs or tetrads (Table 2). There were only two genera that seemed close to the cell arrangement of the EI. The genera were Micrococcus which predominantly shows clusters or tetrads and Salinicoccus which forms pairs, tetrads, and clumps (Table 2). The EI is mostly arranged in clusters or clumps (Table 2). These results left Salinicoccus and Micrococcus as the two genera that the majority of tests in Bergey’s Manual of Determinative Bacteriology match with. Miccrococcus was chosen from the remaining two genera because Salinicoccus prefers moderately saline environment making it much less likely to be found in Arizona mountain soil (Ventosa
The purpose of the study is to identify an unknown microorganism using multiple microbiology lab techniques. Through this process I will gain knowledge on how to perform these techniques as well as the importance of these tests on identifying unknown microorganisms. This is significant as the goal of this course is to familiarize ourselves with the common microbiology tests as well as the microorganisms we encounter in our daily activities.