This document discusses alcohol fermentation by yeast. Yeast converts sugars like glucose, fructose, maltose and sucrose into ethanol and carbon dioxide through a process called alcoholic fermentation. Experiments showed that glucose produced the most barium carbonate precipitate, indicating it underwent the fastest fermentation. Other sugars like glycerol that can't be broken down into glucose did not produce precipitate.

1. ALCOHOL FERMENTATION
 ABSTRACT
 INTRODUCTION
 OBJECTIVES
 METHODOLOGY
 DATA AND RESULTS
 DISCUSSION
 ANSWERS TO QUESTIONS
 CONCLUSION

2. ABSTRACT
Alcohol fermentation is done by yeast and some kinds of
bacteria. These microorganisms convert sugars in ethyl
alcohol and carbon dioxide. Alcoholic fermentation begins
after glucose enters the cell. The glucose is broken down
into pyruvic acid. This pyruvic acid is then converted to
CO2, ethanol, and energy for the cell. Humans have long
taken advantage of this process in making bread, beer, and
wine. In these three products the same microorganism is
used: the common yeast or Saccharomyces Cerevisae.
Hence we used different classification of sugars in
this experiment to verify its feasibility and distinction
in their reaction. Moreover as this experiment aimed to
degrade sugars into its glucose units, the resultant
precipitate will be forming rapidly when we used the
glucose as sugar. The rate of production in getting more Ba
(Co3)2 will depend on the sugar component of the sample
used, as long as it can be degraded into glucose the more
the reaction will be possibly occur.
Keywords:
*anaerobic process *pyruvic acid
*fermentation *sugar

3. INTRODUCTION
 ALCOHOL FERMENTATION- is done by yeast
(Saccharomyces Cerevisae) and some kinds of
bacteria.
 Baker’s yeast- commonly used as a
leavening in baking bread and bakery products.
-a single-celled microorganism
found on and around the human body.
 In the process, these microorganisms convert
sugars in ethyl alcohol and carbon dioxide.
 Alcoholic fermentation begins after glucose
enters the cell. The glucose is broken down into
pyruvic acid. This pyruvic acid is then converted
to CO2, ethanol, and energy for the cell.

4. OBJECTIVES
 To examine the fermentation
property of the different sugars.
 To examine the substrate
specificity of fermentation.

5. METHODOLOGY
yeast

6. METHODOLOGY
Stir the mixture
vigorously 2 hrs in
warm location
Then, after the recovery
of Ba(Co3)2 , weigh the
precipitate, note the
result.

7. DATA AND RESULTS
ALCOHOL FERMENTATION
CARBOHYDRATE AMOUNT OF
PRECIPITATE (g)
Glycerol No precipitate
Glucose 0.60
Sucrose 0.40
Starch 0.20
Fructose 0.20
Maltose 0.20

8. DISCUSSION
 Anaerobic respiration- obtain of energy without
the presence of oxygen.
 Two examples of anaerobic process:
1. Glycolysis- chemical breakdown of glucose to
lactic acid.
2. Alcoholic Fermentation- glucose is broken
down into pyruvic acid. This pyruvic acid is then
converted to CO2, ethanol, and energy for the
cell.
~Therefore, both alcoholic fermentation and
glycolysis are anaerobic processes that begin
with the sugar glucose.

9. Comparison of Glycolysis and
Alcoholic Fermentation

10. DISCUSSION
 Fermentation process- starts with one molecule of
the six carbon sugar-glucose, and terminates with
two molecules of the two carbon alcohol-
ethanol, and two molecules of carbon dioxide.
 Yeast- belongs to the Saccharomyces Cerevisae
species.
- it converts sugars in ethyl alcohol and carbon
dioxide.
 3% Barium hydroxide and mineral oil- the solution
that will react with the yeast and sugar solution.
 Mineral oil- acts as a protection from atmospheric
carbon dioxide that is present in the air.
 Barium carbonate- the final by-product obtain in
the alcohol fermentation.

11. DISCUSSION
 REASONS WHY GLYCOGEN DID NOT PRODUCE
BARIUM CARBONATE:
1. The major role of glycerol is to maintain the redox
balance.
2. Ethanol production in the process ensures reoxidation of
the NADH formed during the oxidation of glyceraldehyde
3-phosphate, is a redox-equilibrated process, excess
NADH is produced during biomass formation.
3. Glycerol is mainly produced to counterbalance this surplus
of NADH and may be considered to form a redox valve.
4. Glycerol production may play an important role in
balancing the ratio of free to bound phosphate in the
cytosol.
5. Essential role of glycerol as a compatible solute during
hyperosmotic stress.

12. ANSWERS TO QUESTIONS
1. Explain why glycerol is not fermented under the
given set condition.
-From the principle of alcohol fermentation, it
convert sugar to ethyl alcohol and carbon dioxide.
In the case of glycerol, which is not a sugar it
cannot be degraded that is why there is no reaction
that occurs in the process. But glycerol is the by-
product produced on alcohol fermentation.
2. How does yeast get fructose into glycolysis?
-The main role of yeast in the process is to
convert sugar to ethyl alcohol and carbon dioxide.
Fructose is a sugar, so yeast reacts with the
hemiacetal side of the fructose and bring fructose
in the process of glycolysis.

13. 3. What class of glycosidase enzyme must yeast
possess to effect fermentation of
carbohydrates?
-In order to effect fermentation, the yeast
must possess the enzyme ALCOHOL
DEHYDROGENASE. It catalyzes ethanolic
fermentation reaction to form ethanol using
glucose (a carbohydrate) as substrate.

14. 4. What monosaccharaides would be produced by
hydrolysis lactose, maltose, sucrose, and starch and
which of these reactions yeast seem able to carry out?
Explain.
-The main monosaccharide that would be produced
is glucose. Of all these reactions, yeast will react more
with maltose because it contains two glucose units.
Glucose is the main sugar that can react fast to yeast
during alcohol fermentation.
5. Write a balance equation for the reaction of gas with
barium hydroxide.
-Barium has a charge of -2 and Oxygen has a charge
of +2. Oxygen is nature appears as O2, therefore
Barium + Oxygen = barium oxide; Ba + O2 = BaO; 2Ba +
O2 = 2BaO

15. CONCLUSION
 ATP(adenosine triphosphate) – main source of
energy in cells.
 Carbohydrates- main source of energy for
organisms.
 Different kind of sugars:
1. Monosaccharides- glucose, fructose, mannose
and galactose.
2. Disaccharides- maltose, sucrose, lactose and
cellobiose
3. Polysaccharides- starch, cellulose and glycogen

16. CONCLUSION
 MONOSACCHARIDES
SPECIFICALLY GLUCOSE = FAST
ALCOHOL FERMENTATION
REACTION+ MORE BY-PRODUCTS
 DISACCHARIDES &
POLYSACCHARIDES = SLOW
ALCOHOL FERMENTATION
REACTION+ LESS BY-PRODUCTS