The nitrates from such sources were used for the manufacture of gun-powder during the Napoleonic wars, long before the microbial process of nitrification was known.
The nitrification process is reversed by many micro-organisms, which are capable of reducing nitrate to nitrite and then to ammonia.
It is agreed that atoms of oxygen are separated in biological oxidation through change in valency of the metal ion Fe in the enzyme cytochrome oxidase. However, in recent years a large number of organisms have been isolated that fix nitrogen non-symbiotically.
The nitrites formed by these organisms are toxic to plants as well as to the organisms forming it. The Essays on nitrogen transformations in which micro-organisms are involved range from elementary nitrogen to protein and other complex organic nitrogenous compounds, with a large number of intermediary substances.
A large number of microbial species including bacteria, yeast, and filamentous fungi assimilate nitrate nitrogen through this process. Since neither the plant nor the bacterium can fix atmospheric nitrogen independently, the process, therefore, is called symbiotic nitrogen fixation.
Nitrogen melts at These compounds are hydrolyzed by various proteolytic enzymes to amino acids and similar compounds. This process is called de-nitrification. Streptomyces and Nocardia oxidize ammonia to nitrite. The bacteria obtain their nutrients and source of energy from the plant, and in turn, fix atmospheric nitrogen and made it available to the plant.
Bacterial cultures for this purpose are available commercially. Seeds inoculated with such cultures assure the presence of desirable strains of Rhizobia as soon as young rootlets are formed.
These reactions are most commonly brought about by Clostridium species. The bacteria aggregate as threads and penetrate the plant cells. It is involved in the metabolism of pyruvic acid. Uses Most of the nitrogen used in the chemical industry is obtained by the fractional distillation of liquid air.
The scarcity of suitable nitrogenous compounds is a major problem in the maintenance of soil fertility. These are strict autotrophs and obtain their energy from the oxidation of ammonia to nitrites and nitrites to nitrates. The atomic weight of nitrogen is This has been achieved by cultivating the micro-organisms in presence of nitrogen labelled with isotopic 15N.
Under anaerobic conditions and in presence of an abundant supply of organic compounds, which serve as hydrogen donors, nitrate serves as an electron acceptor.
Similarly urea present in the urine of man and animals is also decomposed with liberation of ammonia by several micro-organisms specially, by Micrococcus species Proteus species etc. Nitrates are readily used by plants and many micro-organisms.
Nitric oxide which is formed reacts with water to produce nitric acid. In the second step, nitrous acid becomes oxidised and converted into nitric acid, mostly by Nitrobacter. The oxygen is removed from the air, leaving nitrogen mixed with some inert gases.
Thirdly there is a loss by explosives, while this may seem minor except in war, it is actually reasonably large because of blasting of rock, earth etc.
It has been widely recognised for centuries that most crops decrease the fertility of the soil, but leguminous crops increase it.Nitrogen can be obtained from the atmosphere by passing air over heated copper or iron, which removes oxygen and leaves nitrogen and mixed gases.
Pure nitrogen is obtained from liquefied air through a process known as fractional distillation because nitrogen has a lower boiling point than oxygen and can distill off first so it can be collected.3/5(2). Nitrogen is an incredibly versatile element, existing in both inorganic and organic forms as well as many different oxidation states.
The movement of nitrogen between the atmosphere, biosphere, and geosphere in different forms is described by the nitrogen cycle (Figure 1), one of the major biogeochemical cycles. Nitrogen compounds are also important to the making of drugs, dyes, explosives, poisons, and synthetic fibers.
Nitrogen is one of. Essay Nitrogen was isolated by the British physician Daniel Rutherford in and recognized as an elemental gas by the French chemist Antoine Laurent Lavoisier about Properties Nitrogen is a colorless, odorless, tasteless, nontoxic gas. - Nitrogen as a Fertilizer, Nutrient, or Pollutant Nitrogen can always be a fertilizer, nutrient, or pollutant depending on the circumstances and the environment it is in.
As a fertilizer, nitrogen can be extremely useful in aiding the growth of many plants. Biological Nitrogen Fixation: The major share of nitrogen fixation is occupied by biological N 2 fixation. The biological N 2 fixation of atmospheric nitrogen depends on the nitrogenase enzyme system, composed of nitrogenase and nitrogenase reductase.Download