What is the Difference Between Nitrification and Denitrification?

Nitrification and denitrification are two different stages involved in the biogeochemical process of the nitrogen cycle. Here are the key differences between the two processes:

Definition: Nitrification is the biological process of oxidation of ammonia into nitrite, which is then followed by the oxidation of nitrite into nitrate. Denitrification, on the other hand, is the biological process of reduction of nitrate into nitrite, which is then followed by the reduction of nitrite into nitrogen gas.
Reaction: The overall reaction of nitrification is: NH4+ → NO2– → NO3–. The overall reaction of denitrification is: 2 NO3− + 10 e− + 12 H+ → N2 + 6 H2O.
Bacteria Involved: Nitrosomonas and Nitrobacter are the bacteria responsible for nitrification. Lactobacillus, Spirillum, Pseudomonas, and Thiobacillus are the bacteria involved in denitrification.
Mode of Respiration: Nitrification occurs through an aerobic mode of respiration. Denitrification occurs through an anaerobic mode of respiration.
Mode of Nutrition: Nitrification is an autotrophic mode of nutrition. Denitrification is a heterotrophic mode of nutrition.
By-products: The by-product of nitrification is nitrate (NO3–). The by-products of denitrification are nitrogen (N2) and water (H2O).
Temperature and pH: Nitrification requires a minimum temperature between 16° and 35°C and an optimum pH between 6 and 8. Denitrification requires a minimum temperature between 26° and 38°C and an optimum pH between 6 and 8.
Role in the Environment: Nitrification increases soil fertility as the soil absorbs nitrates. Denitrification, on the other hand, decreases soil fertility as the soil loses nitrates to the environment.

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Comparative Table: Nitrification vs Denitrification

Here is a table comparing the differences between nitrification and denitrification:

Feature	Nitrification	Denitrification
Definition	Nitrification is a biological process of oxidation of ammonia into nitrite, which is then followed by the conversion of nitrite into nitrate (NO3–).	Denitrification is a biological process of reduction of nitrate into nitrite, which is then followed by the reduction of nitrite into nitrogen gas (N2).
Reaction	The overall reaction of nitrification is: NH4+ → NO2– → NO3–	The overall reaction of denitrification is: 2 NO3− + 10 e− + 12 H+ → N2 + 6 H2O
Process	Nitrification is a process of oxidation reactions.	Denitrification is a process consisting of reduction reactions.
Nitrogen Cycle	Nitrification is the second step of the nitrogen cycle.	Denitrification is the last step of the nitrogen cycle.
Involvement of Bacteria	Nitrosomonas and Nitrobacter bacteria are involved in nitrification.	Lactobacillus, Spirillum, Pseudomonas, and Thiobacillus bacteria are involved in denitrification.
Mode of Respiration	Aerobic mode of respiration (occurring in the presence of oxygen).	Anaerobic mode of respiration (occurring in the absence of oxygen).
Mode of Nutrition	Chemoautotrophic nutrition (obtaining energy from chemical reactions).	Heterotrophic nutrition (obtaining energy from organic compounds).
End Product	The end product of nitrification is nitrate (NO3–), which increases soil fertility.	The end products of denitrification are nitrogen gas (N2) and water (H2O), which are released into the atmosphere.
Environment	Nitrification occurs in soils, freshwater, and marine systems.	Denitrification occurs in anaerobic environments, such as soils and sediments, and anoxic zones in lakes and oceans.

Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.