The role of microorganisms in nitrogen conversion

Nitrogen is the main component of biological organisms, and the nitrogen cycle is an important biogeochemical cycleThe nitrogen cycle consists of the reactions of 6 kinds of converted nitrogen compounds, including nitrogen fixation, assimilation, ammonia (de-ammonia), nitrification, anti-nitrification and nitrate reduction(1) nitrogen fixation: nitrogen fixation is a biochemical process in which nitrogen in the atmosphere is converted into ammonia (ammonium)Nitrogen-fixing microorganisms have nitrogen fixation genes and nitrogen fixation enzymes synthesized by their codes, and bio-nitrogen fixation is a biochemical process that can be completed only with the participation of microorganisms or microorganisms(2) ammonia: ammonia is the process of converting organic nitride into ammoniaIt is catalyzed by the extracellular and intracellular enzymes of microorganisms and enzymes released by soil animalsThe first is that the extracellular enzyme sequesters degrade the nitrogen-containing organic polymers, which are then absorbed into the cells by microorganisms and metabolize, and the ammonia produced is released into the soilAmmonia released by ammonia can be fixed and further converted by microorganisms(3) nitrification: The nitrification action is the process by which ammonia is oxidized into nitrateunders under oxygen conditionsThe nitricing effect is carried out by two groups of self-fed bacteria, first nitric acid monocytobacteria oxidizes ammonia to nitric acid, and then Bacillus nitrate is then oxidized into nitric acidAmmonia and nitric acid are their energy sources(4) nitrate reduction and anti-nitrification: nitrates in the soil can be reduced by different ways, including assimilation reduction and alienation reduction, the reduction products can be nitric acid, nitrogen oxide, nitrous oxide and so onassimilation reduction refers to the process by which microorganisms gradually reduce the absorbed nitrates into ammonia for cell material reductionPlants, fungi and bacteria are capable of assimilation reduction of NO3-, the formation of NO2-and then NH2OH under the assilystiase catalytic, and finally NH3, from cell assimilation to organic nitrogenThe alienation reduction ofnitratesis more complex and has different ways Due to different microorganisms and conditions, it can be reduced to NO and N2O only, or as molecular nitrogen Only bacteria have NO3-of-the-alienation reduction anti-nitrification, i.e anti-nitrification bacteria in the absence of oxygen conditions, the reduction of nitrates, the release of molecular nitrogen (N2) or nitrous oxide (N2O) process, that is, denitrification Only a few bacteria are able to de-nitrification