Anaerobic Fermentation

Fermentation is commonly defined as the process is which energy is formed by the process of oxidation of organic compounds like carbohydrates and sugars. This leads to conversion of these organic compounds into an acid or an alcohol which provides energy. It can be carried out by microorganisms with the help of oxygen as well as without it. When fermentation is carried out in the presence of oxygen, it is called aerobic fermentation and when carried out without it, it is commonly known as anaerobic fermentation. The basis of fermentation is its metabolic pathways which are carried out with and without the use of oxygen as mentioned earlier, so take a look at all the necessary information you need about anaerobic fermentation in the following article. More on aerobic and anaerobic respiration.

Anaerobic Fermentation Equation

As we have the anaerobic fermentation definition in the introduction of this article, it can be supported with the help of an equation that describes the substrates used in the fermentation process to give the desired products. One of the examples of anaerobic fermentation is alcoholic fermentation whose equation is given below to illustrate how exactly the process of anaerobic fermentation occurs. More on anaerobic bacteria.

						alcohol
Acetaldehyde	+	NADH	+	H	+	-----→	Alcohol	+	NAD	+
						dehydrogenase

In this reaction, anaerobic respiration occurs in the sugars to cause fermentation, with the help of the fungus yeast, which is not in contact with the atmosphere or oxygen. Acetaldehyde and NADH are the substrates of the reaction which are fermented along with one hydrogen ion to form the product which is alcohol. This reaction takes place in presence of the active enzyme alcohol dehydrogenase to give the alcohol and a cofactor which is one ion of NAD. This is what anaerobic fermentation in yeast produces and this reaction follows the decarbaxylation of pyruvate with the help of the enzyme pyruvate decarboxylase, Thiamine pyrophosphate (TPP) and two Mg ions. After this acetyldehyde and CO are formed to give the above mentioned reaction.

Anaerobic Fermentation and Glycolysis

Glycolysis, which is defined as the process of converting glucose to pyruvate, can happen by the anaerobic way. This pathway or transformation of glucose into pyruvate with the help of very limited amounts of oxygen is known as the anaerobic glycolysis. The word 'lysis' means breakdown and 'glyco' means glucose, so from this pathway there is fermentation or breakdown of glucose to pyruvate which is a by-product of the same. This process produces energy (38 ATP molecules) in about 10 seconds to 2 minutes and is carried out in cytoplasm of the muscle cells. This energy is stored in the golgi apparatus inside these cells and then transported as and when required throughout the body.

• Anaerobic glycolysis starts when glucose is phosphorylated into glucose-6-phosphate in the first step. Then this product is further converted into fructose-6-phosphate which is then converted into fructose-1,6-bisphosphate.
• This product then gives two further products viz, PGAL and DHAP which are interconvertable by a reversible reaction.
• The PGAL then produces 1,3-bisphosphoglycerate by reducing one ion of NAD and an inorganic phosphate to NADH.
• This is then followed by the production of 3-phosphoglycerate and 2-phosphoglycerate one after the other with the formation of 1 ATP molecule.
• The 2-phosphoglycerate then gives phosphoenolpyruvate (PEP) by dehydrogenation of one water molecule. This PEP is converted to pyruvate with the generation of another ATP molecule and thus energy is produced by anaerobic fermentation of glucose.

Anaerobic Fermentation and Pickling

Pickling is also a process of anaerobic fermentation and is often called corning or brining. It is called so as foods like raw mangoes and cucumbers are preserved by fermentation in a solution of salt and water called brine. This process can preserve perishable food for months without decaying. These brine tanks have closed lids so to avoid contact with oxygen as that may add other unwanted microbes to grow on the pickles and give a mixture of aerobic and anaerobic fermentation. This strategy of storing foods is very helpful for perishable fruits and vegetables and can be eaten all round the year.

With those major concepts and facts about anaerobic fermentation, I am sure your doubts about it are cleared. As everyone knows fermentation is a very old concept in all the cuisines throughout the world, so don't be afraid to eat those yummy pickles!