Putting 'L' To The Test (Well actually to many tests...)

After an amazing field trip to the local water filtration plant last Thursday, we are back at 'L' in the laboratory. We addressed five tests: Gelatin Hydrolysis, Fermentation of Carbohydrates, Methyl-Red/Voges-Proskauer (MR-VP), Triple Sugar Iron Agar (TSIA) and a litmus milk test. Today, tuesday, we prepared for all these tests and will check the results next lab! (except the litmus test which takes a week to incubate so that will be checked than!)

First up, we have the Gelatin Hydrolysis Test! To prepare for this test we used the aseptic technique with a inoculating needle to stab our bacteria into a gelatin agar slant. We made sure the bacteria made it into the gelatin agar slant by stabbing the needle 3/4 of the way through the gel! Then the slant was placed into teh incubator at 25 degree Celsius. If the bacteria digests the gelatin, than a liquid should appear in the tube when we check it! If it does indeed digest gelatin, then our bacteria has gelatinase, the enzyme that digests gelatin.

The 2nd test was the fermentation of carbohydrates. This test used a broth tube that contained phenol red-sugar broth & a durham tube (which traps gas bubbles). There were three of these tubes and each contained a different sugar. There was a sucrose, a lactose, and a glucose broth. Using aseotic technique we placed our bacteria into each tube to see which carbohydrates our bacteria can digest. We placed the tubes into the incubator at 25 degrees Celsius.

The next test was the Methyl Red/ Voges-Proskauer (MR-VP) test. We used an MR-VP broth and (using aseptic technique) we put bacteria 'L' into the broth tube. Then the broth was placed in the incubator at 25 degree Celsius. Fourth was the Triple Sugar Iron Agar (TSIA) test. We used the aseptic technique & a inoculating needle to transfer bacteria 'L' 3/4 of the way into a TSIA slant. This too was placed in the incubator at 25 degrees Celsus. The last test was the litmus milk test. Using aseptic technique (again! it never gets old ^_^) bacteria 'L' was placed into a Litmus Milk based broth and then into the incubator at 25 degrees Celsius.

Next class we will see the results!
Annie B