1. 1
FERMENTATION OF
CARBOHYDRATES
Presented by: Shalini Saini
M.Sc-Ist-year 2nd
sem
Roll no.-1810

2. 2
Fermentation
Fermentation is the process in which the terminal electron
acceptors and donors are organic compounds.
 It is the conversion of carbohydrate to alcohols
and carbon dioxides, or organic acids using yeast, bacteria
or combination of that under anaerobic condtions(absence
of oxygen.
Implies that the action of microorganisms is desirable.
Complex compounds such as glucose is broken down by the
action of enzymes into simpler compounds without and in
presence of oxygen.
Fermentation result in the production of energy in the
form of two ATP molecules, and produces less energy than
aerobic process of cellular respiration.
C6H12O6 2CO2+ C2H5OH+2ATP

3. 3
Fermentation process
Difference b/w fermentation
And respiration:
Respiration:
C6H12O6+O2 6CO2+CH2O
Fermentation:
C6H12O6 2C2H5OH+2CO2
Energy difference b/w
Fermentation and respiration

4. 4
The chemistry of fermentation were first investigated
by Louis Pasteur in 1860
He called the process la vie sans air, or life without air
In 1897, Hans and Eduard Beuchner discovered that
fermentation could occur in a cell-free extract of yeast
This work led to the elucidation of the enzymes involved
HISTORYHISTORY
MICROORGANISMS INVOLVED IN FERMENTATION OF
CARBOHYDRATES
Saccharomyces uvarum but in some cases Saccharomyces
Cerevisiae lead to the fermentation of carbohydrates.

5. 5
 It is useful to classify worts carbohydrates as fermentable
or non-fermentable on the basis of wether they can be
metabolised by brewer s̓ yeast.
 WORTS-The class of compound present in greater abun-
-dance is carbohydrates. There many less abundant compou-
-nds viz., nitrogenous, inorganic ions, vitamines, polyphenols,
hops compounds, lipids and oxygen.
 Worts is raw materialfrom which beer is made by the
metabolic action of brewer̓s yeast.
 The more important fermentable carbohydrates are;
maltose, maltotriose, glucose, sucrose and fructose.
 Fructose and sucrose come directly from malt; glucose,
maltose, and malitriose are formed during the mashing oper-
-ations and may also added as component of liquid adjunct
(syrup).

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SUMMARY OF GLYCOLYSIS

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PATHWAYS INVOLVED IN FERMNTATION
OF CARBOHYDRATES
 The EMP or glycolytic pathway is one of the more important
And primitive pathway for metabolizing carbohydrates. It
Occurs not only in a large in a large array of aerobic, anaerobic
, and facultative microorganisms but also in mammalian and
other muscle.
The EMP is the principle route by which carbohydrates are
utilized during brewery fermentation.
The 2ATP is required for phosphorylating glucose and
susequently 2ATPs are recovered between glyceraldehyde-3-
Phosphate are readily interconvertible this pathway can
produce a total 4ATPS from each glucose-with a net gain of
2ATPs-and is the main source of cellular energy during
alcoholic fermentations.

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The major pathway of glucose
utilization

9. 9
 Other carbohydrates, such as a galactose, maltose, and
Maltotriose enter this pathway after being converted to
glucose.
Brewer s̓ yeast does not excrete pyruvate but decarboxyl-
-ates it to yield acetaldehyde which is then reduced to
ethanol.
Oxidation-reduction is thereby balanced the NADH
produced during the oxidation glyceraldehyde-3-phosphate to
1,3-diphosphoglyceric acid is utilized in the reduction of
acetaldehyde to ethanol;the NAD+ regenerated in this way is
available for further oxidation of glyceraldehyde-3-
phosphate. Consequently, CO2 and ethanol are the principle by-
Product of this metabolic pathway.

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ALCOHOLIC FERMENTATION
OF CARBOHYDRATES

12. 12
Glucose-6-phosphate
ATP
ADP
Glucose-6-phosphate
EMP
Xylulose-5-phosphate
co2
G3P
Pi
ATP
ADP
Dihydroxyacetone phosphate
Acetyle phosphate
PK
Acetaldehyde
Ethanol
NADH+H+
NAD+
NADH+H+
NAD+
NAD+
NADH+H+
EMP
2(ADP+Pi)
2ATP
Pyruvate CO2
Lactate
2NAD+
2NADH+H+
Glycerol
NADH+H+
NAD+
Pi
Pi
Acetyle-coA

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ALCOHOLIC FERMENTATION
EMP Acetaldehyde Ethanol
HOMOLACTIC FERMENTATION
EMP LACTATE
HETEROLACTIC FERMENTATION
Glucose G6P Xu5P
G3P pyruvate+lactate
+
Acetyle phosphate Acetaldehyde Ethanol

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18. 18
Acetic acid fermentation

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Propionic acid fermentation

20. 20
Fates of Pyruvate

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