Test our bacteria's ability to ferment, utilize, degrade,reduce,andhydrolyze

TEST OUR BACTERIA'S ABILITY TO FERMENT, UTILIZE, DEGRADE, REDUCE, AND HYDROLYZE

Class: Tuesday, October 15th, 2013

We put our bacteria through five different tests today! Too bad we won't be able to see the results until next class because they'll be too busy incubating. So our job today was pretty easy, we were only preparing the tests. There was not much more to do than inoculate the test tubes with our mystery bacteria J and place them in the incubator until next lab.

4 of the tests ready to be inoculated!

Indole test was our first test that we prepared. The purpose of this test is to determine whether our mystery bacteria J can degrade tryptophan into indole and pyruvic acid. To result as positive, our bacteria will have to use tryptophan as energy to degrade the amino acids to make pyruvate. Indole and pyruvic acid would be the left overs that aren't used by our bacteria.

Inoculating the tryptone broth tube

Nitrate Reduction Test is performed in order for us to determine if our mystery bacteria is able to reduce the nitrate ions to produce nitrite ions or nitrogen gas. How does this happen? This test is performed anaerobically so no oxygen will be present. If this will be positive, our bacteria successfully reduced nitrate ions to nitrite ions by adding electrons through the electron transport chain to the nitrate ion. These electrons facilitate the reduction of nitrate ions. If a gas is present in the results, our bacteria will be concluded as positive for reducing nitrate completely to molecular nitrogen. This forms a nitrogen gas.

Inoculating the nitrate broth tube

Urea Hydrolysis Test is used to determine our bacteria J's ability to hydrolyze urea. If our bacteria results as positive, then it had to degrade urea into two byproducts: carbon dioxide and ammonia. We're testing to observe if our bacteria has the enzyme capable to hydrolyze the urea.

Inoculating the urea medium tube

The Methyl Red Test is prepared so we can determine if our bacteria has the ability to ferment glucose through mixed-acid fermentation. Because the products of the mixed-acid fermentation include organic acids, the test observes the pH levels after methyl red is added. If the test results as positive, the methyl red remains red in color indicating the pH is 4.5 and below. A negative test will be yellow or orange.

Inoculating the MR-VP tube

Citrate Utilization Test is performed to determine if our bacteria can utilize citrate as its sole source of carbon and energy. If our bacteria results as positive, then we can conclude that our bacteria has membrane-associated transporter citrate permease. Once our enzymes gets inside of the cell's cytoplasm, they convert citrate into pyruvate (energy) and CO2. If positive, the citrate agar slant tube will transform from green to blue.

Inoculating the citrate agar slant tube