Difference Between Oxidation and Fermentation

The key difference between oxidation and fermentation depends on the type of chemical reaction. Oxidation is the chemical process by which a compound undergoes oxidation in the presence of oxygen while fermentation is the chemical process of producing acids, alcohols and carbon dioxide from sugars in the absence of oxygen.

Oxidation and fermentation are biochemical processes. They occur naturally in living organisms under the influence of enzymes and other cofactors. In the present day, both these natural reactions participate in industrial-scale production of biological molecules. Therefore, understanding these processes and distinguishing the two is of great importance. Hence, this article focuses on discussing the difference between oxidation and fermentation.

CONTENTS

1. Overview and Key Difference
2. What is Oxidation
3. What is Fermentation
4. Similarities Between Oxidation and Fermentation
5. Side by Side Comparison – Oxidation vs Fermentation in Tabular Form
6. Summary

What is Oxidation?

Oxidation is an important biological reaction that primarily takes place in aerobic organisms. It involves the absorption of oxygen by a compound to transform itself into a different compound. Oxidases are the main enzymes that catalyze the reaction of oxidation. Oxidation of biological material can be spontaneous or controlled. Moreover, oxidation of materials may lead to positive and negative effects based on the type of material oxidized. It can also happen via a single step reaction using only one enzyme or can be a multi-step reaction involving many enzymes.

Oxidation plays a major role in most metabolic pathways in higher-level organisms. The pathways that undergo oxidation involve oxidative phosphorylation for production of ATP and beta-oxidation of fatty acids for the production of Acetyl Co A.

Furthermore, oxidation is an important process in the manufacture of fine tea. Instead of performing fermentation, oxidation plays an important role as it does not deplete the polyphenols in the plant. Thus, the conservation of polyphenols in the tea will not harm the quality of the tea. In the production of tea, the enzyme known as polyphenol oxidase is of great importance. When the metabolites known as catechins in tea come in contact with oxygen, the oxidase starts to act, producing polyphenols of higher molecular weight. These polyphenols are thus capable of adding aroma and colour to the black tea. However, in tea production, oxidation takes place under controlled conditions, which differentiate between different tea varieties.

What is Fermentation?

Fermentation is the process that takes place under anaerobic conditions. Therefore, it occurs in the absence of molecular oxygen. Many microbes, plants and human muscle cells are capable of undergoing fermentation. During fermentation, conversion of sugar molecules to alcohols and acids takes place. The chemical reaction has great usage in the industrial production of dairy products, bakery products and alcoholic beverages.

In the natural context, there are two main types of fermentation, both of which require the involvement of enzymes. These two processes are lactic acid fermentation and ethanol fermentation. In lactic acid fermentation, conversion of the pyruvate sugar moiety into lactic acid takes place under the influence of lactic acid dehydrogenase. Lactic acid fermentation primarily occurs in bacteria and in human muscles. The buildup of lactic acid in human muscles leads to the onset of cramps. Ethanol fermentation takes place primarily in plants and in some microbes. The enzymes acetaldehyde decarboxylase and ethanol dehydrogenase facilitate this process.

What are the Similarities Between Oxidation and Fermentation?

• Oxidation and fermentation are biochemical processes that can produce energy in living systems.
• Both processes require the involvement of enzymes.
• Also, these processes start from an organic compound. Hence, the initiation of both processes takes place in the presence of organic compounds.
• Furthermore, they are natural processes taking place in living organisms; however, presently, they are used in many industrial processes.

What is the Difference Between Oxidation and Fermentation?

The two terms oxidation and fermentation are clearly two distinct processes that take place in living organisms. However, both processes can generate energy even though the chemical process behind the two terms differs. Oxidation refers to oxidizing of a compound in the presence of enzymes and molecular oxygen while fermentation refers to the transformation of sugars to acids and alcohols in the presence of enzymes and absence of molecular oxygen. So, this is the key difference between oxidation and fermentation.

Moreover, the type of enzymes utilized during the reactions is also a difference between oxidation and fermentation. Oxidases catalyze oxidation reactions while lactic acid dehydrogenase, acetaldehyde decarboxylase and ethanol dehydrogenase catalyze fermentation. Furthermore, they have a varied amount of applications in the industry. Oxidation is important in the tea industry for the production of polyphenols; in aerobic organisms, it is necessary for the production of energy. On the other hand, fermentation is important in many industrial processes such as dairy industry, bakery industry and alcohol industry, to generate energy in the exercising muscles, etc. Therefore, the usages lead a further difference between oxidation and fermentation.

Summary – Oxidation vs Fermentation

In summarizing the difference between oxidation and fermentation, oxidation is the loosing of electrons from a compound to form another compound in the presence of enzymes and molecular oxygen while fermentation is the process of transforming sugar moieties to acids and alcohols in the absence of oxygen. Both processes play major roles in different industrial processes, even though they are misinterpreted during some instances. Most microbes capable of performing the biochemical reactions of oxidation and fermentation are fundamental in the development of biotechnology-based industrial production processes.

Reference:

1. Jurtshuk, Peter, and Jr. “Bacterial Metabolism.” Medical Microbiology. 4th Edition., U.S. National Library of Medicine, 1 Jan. 1996, Available here.

Image Courtesy:

1. “Linoleic acid beta oxidation” By Keministi – Own work (CC0) via Commons Wikimedia
2. “Ethanol fermentation” By David B. Carmack Jr. – Own work (CC BY-SA 3.0) via Commons Wikimedia