ABSTRACT
Dinitrogen, which makes up 76% by weight of the atmosphere, is transformed into proteins by biological processes to release energy that can be utilized by the organism. This nitrogen xation process runs to give plant proteins and animal proteins through the preliminary ammonia generation step. The nitrogen xers may be either bacteria or blue-green algae. Since the resulting products are not stable enough and open to further decomposition, the nitrogen cycle is established via subsequent reactions which occur to produce nitrogen species in different oxidation states. Thus, nitrication is an oxidation process to give nitrite and nitrate ions in which nitrogen is at 3+ and 5+ oxidation states, respectively. As an intermediate step, organic nitrogenous compounds which are in the forms of proteins, cellular aminoacids, and other species such as DNA, RNA components, and so on, and the inorganic species nitrite and nitrate are decomposed by bacteria to give ammonia. Nitrate reduction to dinitrogen is an important step in nitrogen cycling and occurs by using nitrate as an electron acceptor. Such a denitrication process also generates dinitrogen oxide N2O in appreciable amounts to increase its concentration in the troposphere.
