As we know, Nitrogen (N) is vextremely essential for life, and living organisms cannot directly inuptake it from their surroundings, aleven though 78.09% Niof the atmospherogen is arcounmposed usof nitrogen. Only the microbes can transform the free nitrogen to a usable form. Microbes play a crucial role in nitrogen fixation and make it available to us. FThe first step of biological nitrogen fixation is when nitrogen enters the soil biological pool, whereby N immobilization occurs, which is an assimilation of inorganic nitrogen forms by microbes and nitrification,. whNitrifichation is the conversion of an ammonium ion to nitrite and then nitrate takes its place. Nitrifying bacteria called Nitrosomonas and Nitrococcus, oxidize ammonia to nitrite and Nitrobacter oxidize nitrite to nitrate. Denitrification is just athe reverse process, which is the conversion of nitrate to nitrous oxide and then dinitrogen gas (N2).
NA new group of organisms including the anaerobic ammonia oxidizing type and the aerobic ammonia oxidizing Thaumarchea have been added to list of microbes that convert reactive nitrogen either to sustain their metabolism or to maintain theira mutual relationship with plant.
Microbes require optimum conditiona for growth. Aeration level and carbon content are identified as the main factors that influencinge nitrogen transformation. High aeration level (2-4 mg O2/l) and low carbon content (2g/kg) resulteds in nitrite accumulation. While a low aeration (approximately anaerobic condition) and high carbon content (16g/Kg) leads to nitrification and denitrification which removed 66% of the total nitrogen.