Question

Explain in detail 3 ways by which one can improve on the cyanobacterial nitrogen fixation in the soil environment.

Answer 1

Cyanobacteria have a important role in the nitrogen cycle.Fertilizers work a role they do in part because they contain additional fixed nitrogen which plants can then absorb through their roots. Nitrification cannot occur in the presence of oxygen, so that nitrogen is fixed in specialized cells called heterocysts.

Free-living nitrogen-fixers include the cyanobacteria Anabaena and Nostoc and as Azotobacter.Nitrogen fixation is a process by which nitrogen (N₂) in the atmosphere is converted into ammonia (NH₃). And then Atmospheric nitrogen  (N₂) is relatively inert condition.It does not easily react with other chemicals to form new compounds.Nitrogen fixation is the process by which nitrogen is taken from its stable gas form (N₂) in air and changes into other nitrogen compounds (such as ammonia, nitrate and nitrogen dioxide) useful for other chemical processes. It is an important part of the nitrogen cycle.The major steps of Nitrogen fixation are

• Nitrogen fixation (N2 to NH3/ NH4+ or NO3-)
• Nitrification (NH3 to NO3-)
• Assimilation (Incorporation of NH3 and NO3- into biological tissues)
• Ammonification (organic nitrogen compounds to NH3)

Denitrification(NO3- to N2).

Nitrogen fixation is a process where bacteria in the soil convert atmospheric nitrogen ( N2 gas) into a form that plants can use. The reason this process is so important is that animals and plants cannot use atmospheric nitrogen directly.

Nitrogen fixation is carried out naturally in soil by microorganisms termed diazotrophs that include such as Azotobacter and archaea. Some nitrogen-fixing bacteria have symbiotic relationships with plant groups, especially legumes.Nitrogen fixation is the process by which nitrogen gas from the atmosphere is converted into different compounds that can be used by plants and animals. There are three major ways in which this happens: first, by lightning; second, by industrial methods; finally, by bacteria living in the soil.Legumes are host nitrogen fixing bacteria, and thus are good crops to plant to replenish the soil.

Step 1- Nitrogen Fixation- Special bacteria convert the nitrogen gas (N2 ) to ammonia (NH3) which the plants can use. Step 2- Nitrification- Nitrification is the process which converts the ammonia into nitrite ions which the plants can take in as nutrients.

Fixation by lightning: The energy from lightning causes nitrogen (N₂) and water (H₂O) to combine to form ammonia (NH₃) and nitrates (NO₃). Precipitation carries the ammonia and nitrates to the ground, where they can be assimilated by plants. Biological fixation: About 90% of nitrogen fixation is done by bacteria.

The biochemistry of nitrogen fixation is the nif genes are responsible for the coding of proteins related and associated with the fixation of atmospheric nitrogen into a form of nitrogen available to plants.The nif genes are found in both free living nitrogen fixing bacteria and in symbiotic bacteria in various plants.