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Denitrifying/nitrifying Bacterium

Discussion in 'DAT Discussions' started by osimsDDS, Jun 15, 2008.

  1. osimsDDS

    osimsDDS 5+ Year Member

    Jun 8, 2007
    This is weird I have seen different interpretations of this all over the place I wanted to get it straight maybe you guys can help:

    Denitrifying Bacteria: NH3 to N2
    Nitrifying Bacteria: NO2 to NO3 (nitrite to nitrates)
    Ammonification: NO3 to NH3

    Is this correct?? and if so how does the process work, because i know there are bacteria in legumes and nodules of plants that fix some type of nitrogen, is that N2 to NO2 or NO3??? thanks
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  3. pistolpete007

    pistolpete007 2+ Year Member

    May 18, 2008
    (i know u know most of the stuff im gonna say but for those of who dont know how this works pay attention
    lets start from the beginning the atmosphere is rich in nitrogen but plants cant take up free nitrogen from the atmosphere, there it must be converted into something.
    what is this something? well it can be ammonia or nitrates
    well which one is it? again this depends on the type of plant flowering plants use nitrates more easily than ammonia as a nitrogen source.
    lets start with ammonia....nitrogen fixing bacteria are able to combine atmospheric nitrogen with H to form ammonium ions. This can also be done by cynobacteria. Volcanic activity can directly convert N2 to ammonia as well. the ammonia is then released into the env where it can be taken up and used by plants. Also it should be noted that nitrogen fixing bacteria may live mutualistically with plants and legumes. they will fix nitrogen and supply ammonia directly to plants. once ammonia is absorbed by plants it is converted to amino acids and nitrogen cmpds through enzyme nitrogenase
    now nitrates....the ammonia created by nitrogen fixation goes through two processes to be converted to nitrates this is called nitrification. First bacteria such as nitrosomonas convert ammonuim to nitrites...but nitrites are very toxic to plants so they are converted to Nitrates by bacteria such as Nitrobacter. Nitrates may aslo be produce from atmospheric nitrogen directly through physical processes such as lightning
    decomposition acts on organic sources of nitrogen. which means the nitrogen that has already been incorporated into living organisms. nitrogenous wasts like urine protein and other nitrogen cmpd are freed by bacteria and fungi during the decay of dead plant and animal matter provide 2nd source of nitrogen. through Ammoniafication, these organic cmpd are converted to ammonia ; and nitrification then produces nitrates.
    some elemental nitrogen is returned to atmosphere through action of denitrifying bacteria, which act on NO3- and NO2 to produce N2.

    DRHOYA 2+ Year Member

    May 15, 2008
    Nitrogen Fixing Bacteria form NH4+ from N2 (atmospheric nitrogen). Plants can then take up the NH4+. Now, nitrogen fixing bacteria can live in with legumes (like you said) to supply the NH4+ right to the plant.

    Nitrites are toxic to plants. They are created from a Nitration process that converts the NH4+ to NO2 (nitrites). However, other bacteria convert these harmful nitrites to nitrates (NO3), which are useful for plants.

    Lightening and physical energies can produce Nitrates directly from atmospheric nitrogen, which serves as a direct source for plants.

    Decomposition releases new nitrogen back into the environment. Denitrifying bacteria convert nitrites and nitrates back into atmospheric N2.

    Hope that helps man.
  5. lemoncurry

    lemoncurry tequila mockingbird Administrator Dentist 10+ Year Member

    Aug 20, 2006
    Nitrogen fixing = N2 to NH3
    Nitrifying = NH3 to NO2, further to NO3
    Denitrifying = NO2 to N2
    ammonification = production of ammonia through decomposition, probably due mainly to breakdown of amino acids

    The bacteria that are in nodules of legumes are nitrogen fixing bacteria, which means N2 to NH3.

    One way you can get the full answer is to search on Nitrogen Cycle.

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