Fermentation
- 1. FERMENTATION
- 2. What is Fermentation? An explanation regarding fermentation
- 3. FERMENTATION ■ Fermentation refers to the metabolic process by which organic molecules (normally glucose) are converted into acids, gases, or alcohol in the absence of oxygen or any electron transport chain. 3
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- 5. FERMENTATION ■ Fermentation pathways regenerate the coenzyme nicotinamide adenine dinucleotide (NAD+), which is used in glycolysis to release energy in the form of adenosine triphosphate (ATP). 5
- 6. FERMENTATION ■ The study of fermentation and its practical uses is named zymology and originated in 1856 when French chemist Louis Pasteur demonstrated that fermentation was caused by yeast. 6
- 7. FERMENTATION ■ The processes of fermentation are valuable to the food and beverage industries, with the conversion of sugars into ethanol used to produce alcoholic beverages, the release of CO2 by yeast used in the leavening of bread, and with the production of organic acids to preserve and flavor vegetables and dairy products. 7
- 9. FUNCTION OF FERMENTATION ■ The main function of fermentation is to convert NADH back into the coenzyme NAD+ so that it can be used again for glycolysis. During fermentation, an organic electron acceptor (such as pyruvate or acetaldehyde) reacts with NADH to form NAD+, generating products such as carbon dioxide and ethanol (ethanol fermentation) or lactate (lactic acid fermentation) in the process. 9
- 10. GLYCOLYSIS ■ The breakdown of glucose by enzymes, releasing energy and pyruvic acdi 10
- 12. TYPES OF FERMENTATION ■ The two fermentations most commonly used by humans to produce commercial foods are ethanol fermentation (used in beer and bread) and lactic acid fermentation (used to flavor and preserve dairy and vegetables). 12
- 13. ETHANOL FERMENTATION ■ First, the pyruvate releases carbon dioxide to form a two-carbon compound called acetaldehyde ■ Next, acetaldehyde is reduced by NADH to ethanol, thereby regenerating the NAD+ for use in glycolysis. 13
- 14. ETHANOL FERMENTATION ■ Overall, one molecule of glucose is converted into two molecules of carbon dioxide and two molecules of ethanol. 14
- 15. ETHANOL FERMENTATION ■ Ethanol Fermentation ■ glucose → 2 ethanol + 2 carbon dioxide ■ C6H12O6 → 2 C2H5OH + 2 CO2 15
- 16. LACTIC ACID FERMENTATION ■ There are two main types of lactic acid fermentation: homolactic and heterolactic. 16
- 17. HOMOLACTIC ■ In homolactic acid fermentation, NADH reduces pyruvate directly to form lactate. This process does not release gas. ■ Overall, one molecule of glucose is converted into two molecules of lactate. 17
- 18. HETEROLACTIC ■ In heterolactic fermentation, some lactate is further metabolized, resulting in ethanol and carbon dioxide via the phosphoketolase pathway. 18
- 19. LACTIC ACID FERMENTATION ■ Lactic Acid Fermentation ■ glucose → 2 lactic acid ■ C6H12O6 → 2 C3H6O3 19
- 20. PRODUCTS OF FERMENTATION ■ While there are a number of products from fermentation, the most common are ethanol, lactic acid, carbon dioxide, and hydrogen gas (H2). These products are used commercially in foods, vitamins, pharmaceuticals, or as industrial chemicals. 20