Difference Between Azotobacter and Azospirillum
The Azotobacter vs Azospirillum spp. are discussed below:
Criteria |
Azotobacter |
Azospirillum |
---|---|---|
Definition |
Azotobacter spp. are aerobic, non-symbiotic diazotrophs |
Azospirillum spp. are microaerophilic, associative diazotrophs |
Habitat |
Free living, widely found in soil, water and sediments |
Surface colonising rhizobacteria, commonly found in the rhizosphere or roots of crops like rice, wheat, corn etc. |
Biological interaction |
Non-symbiotic |
Symbiotic or associative |
Oxygen tolerance |
Aerobic |
Microaerophilic, facultative anaerobe |
pH tolerance |
Neutral to alkaline, optimal growth & N2 fixation at pH- 7-7.5 |
Acidic to alkaline, optimal growth & N2 fixation at pH- 7 |
Growth temperature |
Mesophilic bacteria, grows between 25 °C to 30 °C, optimal growth temperature- 30 °C |
Grows between 5 °C to 42 °C, optimal growth temperature- 37 °C |
Shape |
Oval or spherical shape |
Curved rod shape |
Colony characteristics |
Convex, circular, mucoid colonies with dark brown colour |
Flat, circular colonies with red colour |
Family |
Pseudomonadaceae |
Azospirillaceae |
Functions |
|
|
Examples |
Azotobacter chroococcum, Azotobacter vinelandii, Azotobacter beijerinckii |
Azospirillum lipoferum, Azospirillum brasilense, Azospirillum amazonense |
Difference between Azotobacter and Azospirillum
The main difference between Azotobacter and Azospirillum lies in the way these nitrogen fixers are found in nature. The Azotobacter species are non-symbiotic nitrogen-fixing bacteria, whereas the Azospirillum species are associative rhizobacteria that fix nitrogen. Azotobacter are aerobic, free-living species. They are widely distributed in soils and waters. On the contrary, Azospirillum spp. are microaerophilic and often found in a beneficial association with plants.
They are present either in the rhizospheres or the roots of important crop plants. Both of them are diazotrophs, meaning they are capable of biological nitrogen fixation (BNF). In this article, we will look into the differences between Azotobacter and Azospirillum in detail.
Table of Content
- Difference Between Azotobacter and Azospirillum
- What is Azotobacter?
- What is Azospirillum?
- Similarities Between Azotobacter and Azospirillum
- Usage of Azotobacter and Azospirillum
- Conclusion – Difference between Azotobacter and Azospirillum
- FAQs on Difference between Azotobacter and Azospirillum
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