Question

Under anaerobic conditions, denitrifying bacteria, such as pseudomonas could not convert
a. Nitrates to nitrites
b. Nitrates to molecular nitrogen
c. Nitrites to nitrates
d. Nitrates to ammonia

Answer 1

Hint: Denitrification performed by Facultative anaerobic bacteria as a means of respiration In which oxidized nitrogen forms reduced when oxidation of electron donors occurs. The preferred nitrogen electron acceptors, least thermodynamically preferred, include nitrates, nitrites, nitrogen oxides, nitrogen oxides which completes the nitrogen cycle.

Complete answer:
Let’s start with understanding the denitrification process.
In nature, denitrification can occur in terrestrial and marine ecosystems. Denitrification usually occurs in anoxic environments where the concentration of dissolved and freely available oxygen is depleted. In this area, nitrate or nitrite can be used as a substitute for the main electron acceptor in place of oxygen, the electron acceptor which is more energy-efficient. Terminal electron acceptors are compounds that are reduced during a reaction by the formation of electrons. Examples of anoxic environments can include soil, groundwater, wetlands, oil reservoirs, poorly ventilated ocean angles, and sediment from the seabed.
Nitrates are reduced to gaseous nitrogen compounds. The last runaway from the land. Common bacteria that cause soil denitrification are Pseudomonas denitrificans, Thiobacillus denitrificans, and Micrococcus denitrificans.
Nitrous oxides released into the atmosphere or formed during abiological fixation can also be broken down by attack with the formation of molecular nitrogen.

Hence, the correct answer is option (B).

Additional information:
Soil denitrification not only frees the soil of essential nutrients, but it also causes acidification, which is also dangerous when harmful metals are dissolved.

Note: During denitrification, process nitrate is converted into molecular nitrogen. This is known as dissimilatory nitrate reduction. This occurs during a lack of oxygen in the medium. By assimilative reduction of nitrates, nitrites are converted to ammonia. Nitrates added to the soil are reduced to ammonia by enzymatic plants and bacteria, not to nitrogen by bacterial denitrification.