Fermentation of carbohydrates

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fermentation of carbohydrate in microorganisms by follo …

fermentation of carbohydrate in microorganisms by follo

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  • 1. 1 FERMENTATION OF CARBOHYDRATES Presented by: Shalini Saini M.Sc-Ist-year Dept. of microbiology Maharishi Dayanand University, Rohtak (Haryana)
  • 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 HISTORY MICROORGANISMS INVOLVED IN FERMENTATION OF CARBOHYDRATES Saccharomyces uvarum but in some cases Saccharomyces Cerevisiae lead to the fermentation of carbohydrates.
  • 5. 5 TCA cycle
  • 6. 6 The General principles of fermentation • Conservation of energy not by • By chemiosmotic mechanism( proton gradient) But BY Substrate level phosphorylation low ATP and growth yeild eg. Alcoholic fermentation Bacterial fermentation are named by their characteristical end products Alcohol,butyric acid,lactic acid, propionic acid,mixed Acids.
  • 8. 8 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.
  • 9. 9 The major pathway of glucose utilization
  • 10. 10  Other carbohydrates, such as a galactose, maltose, and Maltotriose enter this pathway after being converted to glucose. 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 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.
  • 11. 11
  • 13. 13 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
  • 14. 14
  • 15. 15
  • 16. 16 ALCOHOLIC FERMENTATION EMP Acetaldehyde Ethanol HOMOLACTIC FERMENTATION EMP LACTATE HETEROLACTIC FERMENTATION Glucose G6P Xu5P G3P pyruvate+lactate + Acetyle phosphate Acetaldehyde Ethanol
  • 17. 17
  • 18. 18
  • 19. 19 Acetic acid fermentation
  • 20. 20 Propionic acid fermentation
  • 21. 21 Fates of Pyruvate
  • 22. 22