Which of the following is a non symbiotic aerobic nitrogen fixing bacteria?

Options

A. Beijerinckia
B. Xanthomonas
C. Clostridinum
D. Mycobacterium

Answer

To determine which of the following is a non-symbiotic aerobic nitrogen-fixing bacteria, we will analyze each option provided:

1. **Bacillus**: This is a genus of bacteria that includes several species capable of nitrogen fixation. Some species are free-living and can fix nitrogen without forming symbiotic relationships with plants. However, they are not classified as strictly aerobic.

2. **Xanthomonas**: This is a genus of gram-negative bacteria that are primarily known as plant pathogens. While some species can assist in nitrogen fixation, they do so in a symbiotic relationship with certain plants, particularly in the family Rubiaceae. Therefore, they are not non-symbiotic.

3. **Clostridium**: This genus comprises anaerobic bacteria that can fix nitrogen but do not do so in the presence of oxygen. They are primarily found in environments devoid of oxygen, such as soil and the intestines of animals. Thus, they are not aerobic.

4. **Mycobacterium**: This genus includes bacteria that can also fix nitrogen, but they are typically associated with symbiotic relationships in certain plants. They are known for causing diseases in humans, such as tuberculosis and leprosy, and do not fit the criteria for non-symbiotic bacteria.

5. **Vaserrhinia**: This is the correct answer. Vaserrhinia is a free-living, non-symbiotic aerobic nitrogen-fixing bacterium. It possesses nitrogenase enzymes that allow it to convert atmospheric nitrogen into inorganic compounds, making it capable of fixing nitrogen independently of plant relationships.

### Conclusion:
The correct answer is **Vaserrhinia**, as it is the only non-symbiotic aerobic nitrogen-fixing bacterium among the options provided.