Fermentation Laboratory
Lab Protocol
Activity I
1. Obtain four 250 mL flasks and fill with
approximately 200 mL of tap water. Label the
flasks 1, 2, 3, and 4.
2. Obtain four large test tubes (fermentation tubes)
and label them 1, 2, 3, and 4. Place each
test tube into a separate flask.
3. Using pipette pumps with graduated pipettes, add
solutions as follows to the appropriate tubes. (Do not
cross-contaminate the pipettes!)
Table 1. Contents of Fermentation Tubes (volumes in mL)
Tube DI water
Yeast Suspension Glucose Solution
1
4
0
3
2
6
1
0
3
3
1
3
4
1
3
3
4. Attach a piece of aquarium tubing to the large end of each of four 1-mL graduated
pipettes. Then place a pipette with attached tubing into each test tube containing
the fermentation solutions.
5. Attach the pipette pump to the free end of the tubing on the first pipette. Use the pipette
pump to draw the fermentation solution up into the pipette. Fill the pipette past the
calibrated portion, but do not draw the solution into the tubing. Fold the tubing over
and clamp it shut with the binder clip so the solution does not run out of the pipette.
Open the clip slightly, and allow the solution to drain down to the 0-mL calibration line
(or slightly below). Quickly do the same for the other three pipettes. *NOTE: if you can
not get the solution to the 0-mL mark, then just do your best, mark the starting point
with a wax pencil and note your initial reading in Table 2.
6. Record your initial readings for each pipette. This will be the initial time (I).
7 Two minutes after the initial readings for each pipette, record the actual readings (A) in
mL for each pipette in the “Actual (A)” column. Subtract I from A to determine the
total amount of CO2 produced (I-A). Record this value in the “C02 Evolved (I-A)”
column. From this point on, you will subtract the initial reading from each actual
reading to determine the total amount of CO2, evolved.
8. Continue taking readings every 2 minutes for each of the solutions for 20 minutes.
Remember, take the actual reading from the pipette and subtract the initial reading to get
the total amount of C02 evolved into each pipette.
9. Complete Data Table 1.
1
Table 2. Total CO2 Evolved by Different Concentrations of Yeast
Tube 1
Time
(min)
Actual
(A)
CO2
Evolved
(A-I)
Tube 2
Actual
(A)
CO2
Evolved
(A-I)
Tube 3
Actual
(A)
CO2
Evolved
(A-I)
Tube 4
Actual
(A)
CO2
Evolved
(A-I)
Initial
Reading
(I)
2
4
6
8
10
12
14
16
18
20
Data Table 1: CO2 Evolved by Different Concentrations of Yeast
Fermentation Ratio of Yeast to Glucose Total CO2 Produced
Tube #
(mL:mL)
(20 min)
1
2
3
4
Activity II:
1. Using Activity I as a model, design an experiment testing a variable that you hypothesize
could affect the rate of ethyl alcohol fermentation in yeast. Possible variables include, but
are not limited to temperature, different nutrient molecules, light, etc… Be creative and
most importantly, use good scientific methodology.
2
2. Form a hypothesize concerning your experiment.
3. Run the experiment for at least 20 minutes, collecting and recording data in Table 3.
4. Produce a group laboratory report complete with separate data table(s) and graph.
Tube
1
2
3
4
Tube 1
Time
(min)
Actual
(A)
CO2
Evolved
(A-I)
Tube 2
Actual
(A)
CO2
Evolved
(A-I)
Initial
Reading
(I)
2
4
6
8
10
12
14
16
17
18
19
20
3
Tube 3
Actual
(A)
CO2
Evolved
(A-I)
Tube 4
Actual
(A)
CO2
Evolved
(A-I)