Which one of the following bacteria helps in the denitrification process of nitrates into gaseous nitrogen?

Step-by-step solution

Denitrification is the process of reducing nitrates present in the soil into gaseous nitrogen. This process is carried out by denitrifying bacteria. Nitrosomonas and Nitrosococcus are involved in the first step of nitrification, which is the conversion of ammonia to nitrite. Nitrobacter is involved in the second step of nitrification, converting nitrite to nitrate. Certain species of Bacillus (along with Pseudomonas and Thiobacillus) act as denitrifying bacteria and help in the conversion of nitrates into gaseous n