Nitrification is the biological oxidation of ammonia to nitrite followed by the oxidation of the nitrite to nitrate.

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2. Content..
 Objective
 Introduction about Nitrogen and Nitrogen cycle.
 Nitrification.
 Major steps of Nitrification.
 Denitrification.
 Importance of Nitrification and Denitrification.
 Key difference between Nitrification and
Denitrification.
 Conclusion.
 References.
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3. Objective
 To identify the important roles and the
differences of nitrification and denitrification in
the nitrogen cycle.
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Introduction about Nitrogen and
Nitrogen cycle.
What is Nitrogen?
 Nitrogen is,
• The largest single source in the atmosphere.
(N2-78%)
• An element used to build DNA,RNA and
proteins,this is the building block of life.
 Most living organisms are unable to use nitrogen
as it exists in the atmosphere. (Why ???)
 It can be used by most living organism by travelling
through one of the four processes in the nitrogen
cycle.

5. Nitrogen cycle
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1) Nitrogen fixation
2) Ammonification
3) Nitrification
4) Denitrification

6. Plant absorb nitrates and grow
Ammonium (NH+
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Nitrosomonas
Ammonia change to nitrites(NO2
-)
Nitrobacter
Nitrifying bacteria in soil convert
nitrites to nitrates (NO3
-)
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Nitrification

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 The bacteria are autotrophic and the reaction is
performed under aerobic condition.
 The importance of this step in the nitrogen cycle is
the conversion of ammonia in to nitrate.
 As nitrate is the primary nitrogen source present
in the soil for the plant.

8. Nitrification is a two steps process.
1st step Ammonium oxidation
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Ammonia – oxidizing bacteria are involved,
Ex:- chemoautotrophs sp.
These microorganisms are growing with
ammonia as the energy and co2 as the main
carbon source.

9. These species are distributed in a great variety
of ,
soil
oceans
rivers
lakes
Brackish
environment
Sewage disposal
systems
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2nd Step - Nitrite oxidation
Nitrite oxidizing bacteria are found in aerobic, but
occasionally in anaerobic environments where
organic matter is mineralized.
They are found in the area where the ammonia
oxidizing bacteria are living other than that,
Inside stones and historical buildings
Inside corroded bricks
On concrete surfaces
Cooling towers and high way tunnels

11. How does nitrogen re enter the atmosphere in
the nitrogen cycle?
• This process called “Denitrification’’
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12. What is Denitrification (Important)
• Denitrification is convert Nitrate (N03
-) in the soil to atmospheric
Nitrogen (N2) replenishing the atmosphere.
• Many soil microorganisms are involving.( mostly heterotrophic
bacteria species)
• Denitrifying microbes require very low O2 concentration of less
than 10% .
Examples: Pesudomonas
Achromobacter
Micrococcus
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13. After Nitrification process
Nitrogen in atmosphere closes the Nitrogen cycle (N2)
Process of Denitrification
Nitrite (NO2
- )
Nitrate (N03
- )
Nitric Oxide ( NO)
Nitrous oxide (N2O )
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14. Importance of Nitrification and
Denitrification
Nitrification Denitrifation
• Preferred chemical form of nitrogen
uptake from soil or water.
• Produces accessible plant forms of
nitrogen
• Removes fixed from the ecosystem
• Enhance the greenhouse effect
• Provides nitrate to the plant, which
acts as the important nitrogen source
• Denitrification is used in waste water
treatment and is beneficial for aquatic
habitats
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15. Key Difference Between
Nitrification And Denitrification
Nitrification Denitrification
Meaning  The part of nitrogen cycle where
ammonium is convert into
nitrate.
 The level where reduction of
nitrate is made in to
nitrogen gas.
The process involves  Nitrifying bacteria like
Nitrobacter , Nitrosomonas
 Aerobatic.
 Grow slowly.
 Denitrifying bacteria like
spirillum, lactobacillus .
 Anaerobic.
 Grows rapidly.
PH and temperature  The process occurs at the pH
between 6.5 to 8.5 and
temperature between 16 to 35
degree C.
 The process occurs at the
pH between 7.0to 8.5 and
temperature between 26
to 38 degree C.
End product  Nitrate  Nitrogen
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Conclusion
 Nitrogen is the substantial part of the
atmosphere, as well as plants and animals
also.
 As nitrogen cannot be used directly and so is
transferred in through various sources.
 Nitrification and denitrification are two major
steps in the nitrogen cycle and found
variations in their products and needed.
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T A
H
N
K
Y O U
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