Diazotroph Research Paper

Introduction

What Is Diazotroph?

Diazotrophs are bacteria and archaea that fix atmospheric nitrogen gas into a more usable form such as ammonia. A diazotroph is an organism that is able to grow without external sources of fixed nitrogen. Examples of organisms that do this are rhizobia and Frankia (in symbiosis) and Azospirillum. Types Of Diazotroph?

Diazotroph are across bacterial taxonomic group (mostly in the bacteria and archaea). With a specific that can fix nitrogen may be strain do not fix nitrogen. Fixation is shut off when other sources of nitrogen are available,and many species when oxygen is at high partial pressure. Bacteria have different ways of dealing with the debilitating effects of oxygen on nitrogenases.

Free Living Diazotroph:

These is sufficient ammonia present of suppress nitrogen fixation.

Important:

in terms of generate nitrogen available to all organisms, the symbiotic associations very much exceed the free-living species with the exception of cyanobacteria.

The world's growing population, depends ultimately on plants for food.They in turn depend on supply of nutrients, especially nitrogen compounds, in the soil. In world agriculture today, the natural processes for replenishing nitrogen used up by crops are too slow to sustain the productivity needed, and the shortfall is made up by chemical fertilizers, prepared industrially by taking nitrogen from the atmosphere, the Haber process. A few type of bacteria, collectively called, diazotrophs (di = two, azo = nitrogen, troph = feeder}, can use nitrogen from the atmosphere, but plants can not.

The most important factor possessed by diazotrophs is the enzyme nitrogenase, the key enzyme which converts dinitrogen to ammonia, coded by a cluster of genes called nif. This process requires energy which amongst diazotrophs in cyanobacteria is supplied by

Nitrogen fixation in association with roots of grasses and cereals' is not a novel concept, but practically our knowledge about the nature of these systems has gained importance in last 15-20 years]. Nitrogen fixing bacteria of many diverse genera occur in high numbers in the rhizosphere of the roots of a variety of grasses. Most notable among these are Azospirillum, Azotobacter, Beijerinckia and Derxia.

Nitrogen is commonly considered one of the foremost restrictive nutrients in plant growth and the major reserve of nitrogen in the biosphere being available in the form of atmospheric nitrogen (molecular nitrogen) which actually cannot be utilised by the plant. The atmospheric nitrogen are made available to the plants when nitrogen fixing bacteria or rhizobia fixed atmospheric nitrogen and convert them into ammonia (NH3) in the presence of nitrogenase under different conditions such as, in loose association with other organisms, or in a symbiotic manner with them. The process whereby atmospheric nitrogen is reduced to ammonia in the presence of nitrogenase (found naturally in microorganisms viz. Rhizobium, free living Azotobacter etc) is called Biological nitrogen fixation (BNF). The best example for the symbiotic