Fermentation of carbohydrates

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Fermentation of carbohydrates

  1. 1. 1 FERMENTATION OF CARBOHYDRATES Presented by: Shalini Saini M.Sc-Ist-year 2nd sem Roll no.-1810
  2. 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. 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. 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. 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).
  6. 6. 6 SUMMARY OF GLYCOLYSIS
  7. 7. 7 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.
  8. 8. 8 The major pathway of glucose utilization
  9. 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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  11. 11. 11 ALCOHOLIC FERMENTATION OF CARBOHYDRATES
  12. 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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  14. 14. 14
  15. 15. 15 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. 18 Acetic acid fermentation
  19. 19. 19 Propionic acid fermentation
  20. 20. 20 Fates of Pyruvate
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