Question

what is. a nitrogen fixing bacteria

Answer 1

The primary function of these bacteria is 'Survival' and in their efforts directed towards this goal, they enter into a symbiotic relationship with leguminous plants or some survive on their own. As a part of their metabolic cycle, they fix nitrogen.  

An enzyme which these bacteria use is called 'Nitrogenase'. It is a chemical, responsible for nitrogen fixation, without which, this process is impossible. The process at chemical level, that enables nitrogen fixation, can be summarized as follows:

N2 + 6 H+ + 6 e- → 2 NH3

Answer 2

Nitrogen fixing bacteria mainly present in the Soil or in plant roots that changes nitrogen gases from the Atmosphere into solid nitrogen compounds that plants can use in the soil .

example :- Bacillus polymyxa