Published on March 11, 2014
1 FERMENTATION OF CARBOHYDRATES Presented by: Shalini Saini M.Sc-Ist-year 2nd sem Roll no.-1810
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 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 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 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 SUMMARY OF GLYCOLYSIS
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 The major pathway of glucose utilization
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.
11 ALCOHOLIC FERMENTATION OF CARBOHYDRATES
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
15 ALCOHOLIC FERMENTATION EMP Acetaldehyde Ethanol HOMOLACTIC FERMENTATION EMP LACTATE HETEROLACTIC FERMENTATION Glucose G6P Xu5P G3P pyruvate+lactate + Acetyle phosphate Acetaldehyde Ethanol
18 Acetic acid fermentation
19 Propionic acid fermentation
20 Fates of Pyruvate
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