1
FERMENTATION OFCARBOHYDRATES
Presented by: Shalini SainiM.Sc-Ist-year Dept. of microbiologyMaharishi Dayanand University,Rohtak (Haryana)
2
FermentationFermentation is the process in which the terminal electronacceptors and donors are organic compounds. It is the conversion of carbohydrate to alcoholsand carbon dioxides, or organic acids using yeast, bacteriaor 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 thanaerobic process of cellular respiration.
C6H12O6 2CO2+ C2H5OH+2ATP
3
Fermentation process
Difference b/w fermentationAnd respiration:
Respiration:C6H12O6+O2 6CO2+CH2O
Fermentation:C6H12O6 2C2H5OH+2CO2
Energy difference b/wFermentation and respiration
4
The chemistry of fermentation were first investigated by Louis Pasteur in 1860He called the process la vie sans air, or life without airIn 1897, Hans and Eduard Beuchner discovered that fermentation could occur in a cell-free extract of yeastThis work led to the elucidation of the enzymes involved
HISTORYHISTORY
MICROORGANISMS INVOLVED IN FERMENTATION OFCARBOHYDRATES
Saccharomyces uvarum but in some cases SaccharomycesCerevisiae lead to the fermentation of carbohydrates.
5
TCA cycle
6
The General principles of fermentation
• Conservation of energy not by• By chemiosmotic mechanism( proton gradient)But BYSubstrate level phosphorylation low ATP and growth yeild eg. Alcoholic
fermentationBacterial fermentation are named by their
characteristical end productsAlcohol,butyric acid,lactic acid, propionic acid,mixedAcids.
7SUMMARY OF GLYCOLYSIS
8
PATHWAYS INVOLVED IN FERMNTATIONOF 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.
9
The major pathway of glucose utilization
10
Other carbohydrates, such as a galactose, maltose, and Maltotriose enter this pathway after being converted toglucose.Brewer̓ s 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 to1,3-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.
11
12
ALCOHOLIC FERMENTATION OF CARBOHYDRATES
13
Glucose-6-phosphateATPADP
Glucose-6-phosphate
EMP
Xylulose-5-phosphateco2
G3PPi
ATPADP
Dihydroxyacetone phosphateAcetyle 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
14
15
16
ALCOHOLIC FERMENTATION
EMP Acetaldehyde Ethanol
HOMOLACTIC FERMENTATION
EMP LACTATE
HETEROLACTIC FERMENTATION
Glucose G6P Xu5P G3P pyruvate+lactate
+Acetyle phosphate Acetaldehyde Ethanol
17
18
19
Acetic acid fermentation
20
Propionic acid fermentation
21
Fates of Pyruvate
22
Top Related