Question

Azotobacter and Beijerinckia are example of
A. Symbiotic nitrogen fixing bacteria
B. Asymbiotic nitrogen fixing bacteria
C. Photosynthetic
D. Disease causing bacteria

Answer 1

Microorganisms that are capable of transforming atmospheric nitrogen into fixed nitrogen (inorganic compounds usable by plants). More than 90 % of all nitrogen fixation is affected by these organisms, which thus play an important role in the nitrogen cycle.

Complete answer: Both the bacteria Azotobacter and Beijerinkia are free living, nitrogen-fixing, aerobic microbes. They play an important role in the nitrogen cycle in nature bindinding atmospheric nitrogen, which is inaccessible to plants, and releasing it in the form of ammonium ions into the soil ( nitrogen fixation ).
In addition to being a model organism, for studying diazotrophs ( bacteria and archaea that fix nitrogen gas into a more usable form ammonia ), it is used by humans for the production of biofertilizers, food additives and some biopolymers. All diazotrophs contain iron-molybdenum or vanadium nitrogenase systems. These systems are used because of their genetic tractability and their fast growth.Thus from the explanation we can understand that the correct option is – A that is Symbiotic nitrogen fixing bacteria and rest options are incorrect options.
So, the correct answer is “Option A”Symbiotic nitrogen fixing bacteria.

Note: Nitrogen cycle is a biogeochemical process through which nitrogen is converted into various forms consecutively passing from the atmosphere to the soil to organism and back into the atmosphere. It involves several processes such as nitrogen fixation, nitrification, denitrification, decay and putrefaction.