Nitrogen Fixation

Abstract

Nitrogen fixation converts inert atmospheric molecular nitrogen gas into reduced forms whereby the nitrogen may be used by all life forms for protein and nucleic acid production. The biological process occurs only in microorganisms and is the principal contributor of fixed nitrogen to the biosphere. Fixed nitrogen is also derived from nonbiological processes, such as fires, volcanoes, and lightning, and from industrial fixation. The Haber‐Bosch ammonia process is highly energy‐intensive but is the most economical industrial process available. Agriculturally, the most important source of biologically fixed nitrogen is the symbiotic system involving leguminous plants which harbor rhizobia bacteria in nodules on their roots. Smaller contributions are made by other, less formal systems and by free‐living microbes. All of the biological systems use a similar metalloenzyme complex, called nitrogenase. Nitrogen fixation research is discussed from a genetic standpoint, as well as in terms of model chemistry and economic advantages of the biological system. The chemical approaches aimed at duplicating the biological process are presented.

Isolation and Characterization of Plant Growth Promoting Bacteria Isolated from Andean Soil as Potential Inoculants of Soybean Seeds

“…The main reserve of nitrogen in the biosphere is molecular nitrogen from the atmosphere. Nevertheless, plants cannot directly assimilate the molecular nitrogen, but it becomes available through the biological nitrogen fixation process "BNF" (Newton, 2000;Franche et al, 2009). Many species of microorganisms are used in the cultivation of plants, facilitating the host plant growth without the use of nitrogenous fertilizers, becoming economic interest.…”