FERMENTATION PROCESSES AND THEIR APPLICATION.pdf

means “with air”. This type of respiration needs oxygen for it to occur so

it is called aerobic respiration. Glucose + Oxygen -> Carbon dioxide + Water + Energy The chemical equation is: C6H12O6 + 6O2

-> 6CO2 + 6H2O + 2900 kj

1. glycolysis In glycolysis, a net of 2 molecules of ATP , or chemical energy, are produced. 2. citric acid cycle The citric acid cycle produces another 2 molecules of ATP  3. electron transport chain The electron transport chain produces 28 molecules of ATP .  is used in aerobic cellular respiration as the final electron acceptor in the electron transport chain, which is part of why it is able to create so much ATP.

In anaerobic cellular respiration, the only step of this process that occurs is glycolysis.

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Derived from the Latin verb ‘ fervere ’ meaning ‘to boil’

It is a process by b y which the living cell is able a ble to obtain energy through the breakdown of glucose and other simple sugar molecules without requiring oxygen.

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 results in the production of energy in the form of two ATP molecules, and produces less energy than the aerobic process of cellular respiration .  in the 19th century used the term fermentation in a narrow sense to describe the changes brought about by yeasts and other microorganisms growing in the absence of air (anaerobically); he also recognized that ethyl alcohol and carbon dioxide are not the only products of fermentation.

In , the pyruvic acid from glycolysis loses one carbon in the form of carbon dioxide to form acetaldehyde, which is reduced to ethyl alcohol by NADH. When acetaldehyde is reduced to ethyl alcohol, NADH be comes NAD + (is oxidized). This is the fermentation that commonly occurs in yeast. Like lactic acid fermentation, alcoholic fermentation allows glycolysis to continue by ensuring that NADH is returned to its oxidized state (NAD +).

Figure 1. The alcoholic a lcoholic fermentation fermentation process  Alcoholic fermentation fermentation of glucose: glucose:

In lactic acid fermentation, the pyruvic acid from glycolysis is reduced to lactic acid by NADH, which is oxidized to NAD +. This commonly occurs in muscle cells. Lactic acid fermentation allows glycolysis to continue by ensuring that NADH is returned to its oxidized state (NAD +).

Figure 2. The lactic acid fermentation process

There are five major groups of commercially important fermentations: (i) Those that produce microbial cells (or biomass) b iomass) as the product. (ii) Those that produce microbial enzymes. (iii) Those that produce microbial metabolites. (iv) Those that produce recombinant products. (v) Those that modify a compound which is added to the fermentation the transformation process.

(i) The  of media to be used in culturing the process organism during the development of the inoculum and in the production fermenter. (ii) The

 of the medium, fermenters and ancillary equipment.

(iii) The  of an active, pure culture in sufficient quantity to inoculate the production vessel. (iv) The  in the production fermenter under optimum conditions for product formation. (v) The

 and its purification. p urification.

(vi) The

 produced by the process.

 A  is special medium used in microbiological laboratories to grow different kinds of microorganisms. A  is composed of different nutrients that are essential for a microbial growth.

The  is a liquid selective media which w hich is used to obtain a culture of a specific organism more likely yeast or a particular pa rticular toxin.  can also be differential but mostly it is selective in nature that is allowing the growth of one type while inhibiting the growth of others.

The end products of fermentation differ depending depending on the organism. organism. produced from many bacteria, fungi, protists, and animals cells (notably muscle cells in the body) •

Figure 3. Lactic acid structure produced from  yeast  and  and most

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 plant cells 

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from milk (yogurt, kefir, fresh and ripened cheeses), fruits (wine, vinegar), vegetables (pickles, sauerkraut, soy sauce), meat (fermented sausages, salami) (solvents: acetone, butanol, ethanol, enzymes, amino acids) (vitamins, pharmaceuticals)

Figure 4. Fermentation products

It is a simple fermentation of sugar to CO 2 and alcohol. Baking Soda and Cream of Tartar Reactions:

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Baking soda

Cream of tartar

Potassium water carbon dioxide hydrogen tartrate

Figure 5. Bread manufacturing process

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 Yogurt forms when bacteria ferment the the sugar lactose (C 12H22O11) into lactic acid (C 3H6O3). The lactic acid makes the milk more acidic a cidic (lower the pH), causing the proteins in milk to coagulate. Two bacteria: Streptococcus thermophilus   and Lactobacillus bulgaricus 

Figure 6. Yogurt manufacturing process

The main ingredient in cheese is milk. Cheese is made using cow, goat, sheep, water buffalo or a blend of these milks. Cultures for cheese making are called lactic acid bacteria b acteria (LAB) because their primary source of energy is the lactose in milk and their primary metabolic product is lactic acid. There is a wide variety of bacterial cultures available that provide distinct flavor and textural characteristics to cheeses.

Figure 6. Breakdown of lipids in milk The breakdown of the lipids in milk yields carboxylic acids, the source of a range of smelly molecules.

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In acetone-butanol fermentation, acetone and butanol are produced from glucose using strains of Clostridia , which are strictly anaerobic bacteria. Further, ethanol is also produced. Two distinct metabolic pathways exist, one producing butanol from starch, the other producing butanol from sucrose. It yields 3 parts of acetone, 6 of butanol and 1 of ethanol.

The growth of used in the production of amino acids is done in a well balanced ba lanced environment. The conditions required a controlled pH of the fermentation medium (approximately neutral); neutral); Rich growth media; highly aerobic conditions; sterile conditions

Figure 6. Production of Monosodium glutamate by fermentation

Generally, amino acids can not be manufactured in quantities without deactivating the regulatory mechanism that microorganisms possess. However, the glutamate-producing microorganism microorganism has such a rare characteristic that glutamate can be produced solely by setting special fermentation conditions without improving the strain.  A fermentation tank tank is fed with raw materials such such as syrup derived from from sugar cane, and glutamate-producing glutamate-producing microorganisms are fermented under the appropriate conditions. During this fermentation process, glutamate is excreted from the microorganisms into the fermented broth. This is how glutamate is obtained in large amounts.