Fermentation is the process of chemical breakdown of any organic substanceby different bacteria like yeast etc. It is defined as” the process of incomplete oxidation of sugar, espicially glucose, into alcohol and carbondioxide.” This process is done in the absence of air, so it an anaerobic process. In other it is the process in which gulcose is breakdown into pyruvic acid by glucolysis which is again degarded enzymetically to alcohol and carbon dioxide.
Fermentation is the only one biotechnology we have been following from our anccient time. This technique was started by our forfather and still we are following this process but in modern way. In ancient time people use to make alcohol from the different grains and fruits. Alcohol is the first biological product produced. Now fermentation is done commercially for the production of alcohol.
Different bacteria and fungi are used for the process of fermentation and yeast is one of the popular fungi used for this process. Saccharomyces cerevisae is a microscopic fungus. Louis pasture was the first person to report the activity of yeast in the process of fermentation in the nineteenth century. Now yeast is used industrially for the production of different products that are consumed by both animals and human. There are two types of yeast. They are mentioned below:
Barley Malt, grains
Fermented molasses of sugarcane
Table: Alcoholic liquor
Due to the consumption of the sugar such as glucose and fructose yeast is able to maintain the stoke ATP (Adenosine Tri-phosphate). Sugarcane juice contains sucrose, which is the type of sugar composed of one glucose molecule attached to the molecule of fructose. When the yeast grown in the oxygenated medium is bring in contact to the sugar, than the sugar is break down into a smaller and smaller molecule step by step and finally carbon dioxide and energy is obtained. When the sugar is bring in contact with the yeast which is not grown in the oxygenated medium than a series of chemical process will be completed and as a result ethanol or fuel alcohol is obtained.
Through the glucolysis process glucose can be splitted up into two molecules of pyruvic acids which are enzymetically degraded into alcohol and carbon dioxide by fermentation process. The yeast which help in fermentation of alcohol contain two essential enzymes, they are: pyruvate decarboxylase and alcohol dehydrogenase. Pyruvic acid is converted into acetaldehyde in presence of pyruvate decarboxylase and acetaldehyde is further converted into ethanol in presence of alcohol dehydrogena se by NADH.
Molasses is the raw material used in the preparation of alcohol in the industries which is thick and dark syrup drained out form the refining process of raw sugar.
In the process of manufacture of alcohol in industries, molasses mash is adjusted to the desired sugar concentration and temperature by adding water and by adding measured quantity of acid or base wanted pH of the alcohol can be obtained. Molasses is kept in the fermentation tank known as bioreactor. In the bioreactor molasses mash is uniformly mixed with yeast (Saccharomyces) which is called starter. The well mixed mash and starter spatter and false to the bottom of tank. Soon the fermentation becomes vigorous and large amount of carbon dioxide is evolved. Within fifty hours or less the fermentation process is completed. Then after fermented molasses is distilled and alcohol is separated as well as other volatile constituents. The produce alcohol is purified by the means of rectifying columns and store in the container.
Fermentation is done with one of the following method
Along with the alcohol carbon dioxide is produced as the bye product which is collected separately. Yeast cells are also isolate from fermented product and a part of yeast is kept further inoculation. The remaining yeasts used as the feeds for animals when they are dried and washed.
Bioreactor is defined as the vessel or a container which is designed is such a way that can provide an optimum environment in which microorganisms or their enzymes interact with a substrate to produce the required product. There are two types of bioreactor which are mention below:
Now a day different alcoholic beverages are produced in industries. People in all over the world consume different fermented alcoholic beverages. Some of the alcoholic beverages are described below:
Fermentation has different application in the industrial sector. Some of them are as follows:
Arvind K. Keshari,Kamak K. adhikari. A Text Book of Higher Secondary Biology. Kathmandu: Vidyarthi Pustak Bhandar, 2014.
Agrawal, sarita. principle of biology. 2nd edition . kathmandu: Asmita book Publication, 2068 ,2069
Mehta, Krishna Ram. Principle of biology. 2nd edition. kathmandu: Asmita, 2068,2069.
Jorden, S.L. principle of biology. 2nd edition . Kathmandu: Asmita book Publication, 2068.2069.
1. Fermentation is the process of chemical breakdown of any organic substanceby different bacteria like yeast etc.
2. Louis pasture was the first person to report the activity of yeast in the process of fermentation in the nineteenth century.
3. Pyruvic acid is converted into acetaldehyde in presence of pyruvate decarboxylase and acetaldehyde is further converted into ethanol in presence of alcohol dehydrogena se by NADH.
4. In the process of manufacture of alcohol in industries, molasses mash is adjusted to the desired sugar concentration and temperature by adding water and by adding measured quantity of acid or base wanted pH of the alcohol can be obtained.
5. All the process involves after the fermentation process is known as the downstream process.
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