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the continuous sequence of natural
processes by which nitrogen in the
atmosphere and nitrogenous compounds in
the soil are converted, as by nitrification
and nitrogen fixation.
Winogradsky discovers the organisms
responsible for nitrification is soil, which is of
great importance in agriculture because
nitrogen is a limiting nutrient in the soil.
M.W.Bejerinck discover symbiosis nitrogen
Nitrogen is part of amino acid, proteins and nucleic
acid and is often a limiting plant nutrient and many
other use of nitrogen.
All organisms require nitrogen to live and grow.
The main avability of nitrogen is the atmosphere,
which is 80%free nitrogen gas.
Nitrogen are including two forms inorganic and
The process of converting N2 into biologically
available nitrogen is called nitrogen fixatation
nitrogen-fixing organisms are two type.
The whole process requires eight electrons
and at least sixteen ATP.
Rhizobium is most importance bacteria in
Rhizobium can infect the roots of a
leguminous plant (such as peas, clover,
Nitrification is the process that converts
ammonia to nitrite and then to nitrate.
There are two distinct steps of nitrification.
The first step is the oxidation of ammonia to
ammonia oxidation was carried out by only a
few types of bacteria in the genera
Nitrosomonas, Nitrosospira, and Nitrococcus.
The second step in nitrification is the
oxidation of nitrite (NO2-) to nitrate (NO3-).
the second step was carried out by bacteria
such as a Nitrobacter.
Denitrification is the process that converts
nitrate to nitrogen gas.
Some denitrifying bacteria include species in
the genera Bacillus, Paracoccus, and
Denitrification is important in that it removes
fixed nitrogen from the ecosystem.
Anammox bacterium was Brocadia
it is anaerobic bacteria.
Anammox bacteria oxidize ammonia by using
nitrite as the electron acceptor to produce
It is found in aquatic systems and low
oxization zones of ocean
When an organism excretes waste or dies, the
nitrogen in its tissues is in the form of
organic nitrogen (e.g. amino acids, DNA).
Various fungi and prokaryotes then
decompose the tissue and release inorganic
nitrogen back into the ecosystem as ammonia
in the process known as ammonification. The
ammonia then becomes available for uptake
by plants and other microorganisms for
Nitrogen in air
NO2- and NO3-
Rhizobium and Aztobactor
Elden D enger ,F.c ross and DB
Bailey(2005)concept in biology