Microbiology Unknowns Lab Report
Escherichia coli
Microbiology Lab
NAS 185-14L
Introduction
In this lab experiment we did several test to determine what our unknown bacteria was. To determine this we recorded the results of how the bacteria reacted to different media. Depending on the results of each test we could narrow down the different bacteria to determine what our unknown is. This experiment will also determine if our bacteria is a fermenter of sugars and if it is catalase positive. If the bacteria is a fermenter they will use the sugars to make ATP. If the bacteria is a fermenter of lactose/sucrose the EMB plate we used will “clearly differentiate between the colonies of lactose fermenting and non-fermenting microbes. In the same medium sucrose was also included to differentiate between coliforms that were able to ferment sucrose more rapidly than those that were unable to ferment sucrose” (Cheeptham & Lal, 2007).
If it is catalase positive it will produce bubbles with the drops of hydrogen peroxide on the bacteria. This will show if the bacteria is an aerobic or aero tolerant anaerobes or true anaerobes. Catalase is an enzyme that will take hydrogen peroxide and break it down to water and oxygen.(Merriam Webster 2013) “Catalase is thought to be a major defense against hydrogen peroxide” (Eaton & Ma, 1992).
We will also determine if the bacteria is stable or non-stable acid fermenters. If it is stable it will produce the acid and it will be a positive result. This test will tell us the pathway of fermentation. Another thing we will determine is that if there will be a presence of citrate permease. Which will increase the ph level. (Health and Life Sciences Department 2013)
By doing these tests we will be able to see how the unknown bacteria reacts to certain conditions. If our results of these lab experiments are conclusive then we should be able to determine what our unknown bacteria is.
Materials and Methods
Tube with unknown
Microbiology Lab
NAS 185-14L
Introduction
In this lab experiment we did several test to determine what our unknown bacteria was. To determine this we recorded the results of how the bacteria reacted to different media. Depending on the results of each test we could narrow down the different bacteria to determine what our unknown is. This experiment will also determine if our bacteria is a fermenter of sugars and if it is catalase positive. If the bacteria is a fermenter they will use the sugars to make ATP. If the bacteria is a fermenter of lactose/sucrose the EMB plate we used will “clearly differentiate between the colonies of lactose fermenting and non-fermenting microbes. In the same medium sucrose was also included to differentiate between coliforms that were able to ferment sucrose more rapidly than those that were unable to ferment sucrose” (Cheeptham & Lal, 2007).
If it is catalase positive it will produce bubbles with the drops of hydrogen peroxide on the bacteria. This will show if the bacteria is an aerobic or aero tolerant anaerobes or true anaerobes. Catalase is an enzyme that will take hydrogen peroxide and break it down to water and oxygen.(Merriam Webster 2013) “Catalase is thought to be a major defense against hydrogen peroxide” (Eaton & Ma, 1992).
We will also determine if the bacteria is stable or non-stable acid fermenters. If it is stable it will produce the acid and it will be a positive result. This test will tell us the pathway of fermentation. Another thing we will determine is that if there will be a presence of citrate permease. Which will increase the ph level. (Health and Life Sciences Department 2013)
By doing these tests we will be able to see how the unknown bacteria reacts to certain conditions. If our results of these lab experiments are conclusive then we should be able to determine what our unknown bacteria is.
Materials and Methods
Tube with unknown