AZOTO

C, H, N, O compongono 96% del materiale vivente

78% aria (in peso)

secondo elemento piu’ abbondante nel corpo umano

Fissazione dell’azoto di tipo biologico

•Batteri simbionti (associati alle radici delle leguminose)

Rhizobium

•Batteri “liberi” nel suolo (Azotobacter)

arricchimento di azoto (NH4+) nel terreno

NITRIFICAZIONE

conversione ammonio nitrato

“ossidazione” in terreni aerati

Nitrosomonas NH3 NO2-

Nitrobacter NO2- NO3-

AMMONIFICAZIONE

conversione nitrato ammonio

Nitrato: azoto biodisponibile per eterotrofi (aa e acidi nucleici)

Azione dei funghi decompositori

DENITRIFICAZIONE

conversione nitrato azoto N2

Pseudomonas

Did you know?1.That most of the air we breathe is made by anammox bacteria?2.That anammox bacteria divide only once per two weeks at maximum speed?3.That hydrazine (rocket fuel) and nitric oxide are the anammox intermediates?4.That these intermediates are turned over in an organelle surrounded by an impermeable membrane made of ladderane lipids?5.That anammox bacteria share a common ancestor with the parasitic chlamydia?6.That you can download the anammox genome HERE?

Partial nitrification/Anammox® is a new method for nitrogen removal from wastewater. It targets wastewater streams (or gases) high in ammonium (>0.2 g/l) and low in organic carbon (C:N ratio lower than 0.15). The two processes proceed as follows:

(the produced acid is balanced by the counter-ion of ammonium, usually bicarbonate or sulfide)

(partial nitrification) 2NH4+ + 1.5O2 => NH4

+ + NO2- + H2O + 2H+

(anammox) NH4+ + NO2

- => N2 + 2H2O

(total) 2NH4+ + 1.5O2 =>N2 + 3H2O + 2H+

STECHIOMETRIA:

1 NH4+ + 1.32 NO2

- +

0.066 HCO3- + 0.13 H+

=

1.02 N2 + 0.26 NO3- + 0.066 CH2O0.5N0.15 + 2.03 H2O

Optimum:6°C<T<43°C6.7<pH<8.3DO<0.5%NO2

- <20mM

anammox process is based on energy conservation from anoxic ammonium oxidation with nitrite as the electron acceptor and hydrazine as the intermediate.

CO2 is used as the main carbon source for growth. Recently we learned

that CO2 fixation is accomplished via the acetyl-CoA pathway.

The necessary electrons are obtained from the anaerobic oxidation of nitrite to nitrate

anammox mechanism with hydrazine and nitric oxides as intermediates;

reversed electron transport to upgrade electrons from nitrite oxidation to drive anammox carbon fixation via the acetyl CoA pathway

They lack the otherwise universal bacterial cell wall polymer peptidoglycan, they divide by budding, and they have a differentiated cytoplasm.. They are separated from other bacteria and amongst themselves by large evolutionary distances. Other species of planctomycetes are aerobic chemoorganoheterotrophs, very different from the anammox bacteria

planctomycetes

The first full scale anammox reactor, Rotterdam, the Netherlands. It works at design load and removes over 500 kg N/day