Explanation:

• Ammonifying bacteria are those bacteria that convert atmospheric nitrogen into ammonia. These are also called as nitrogen fixing bacteria. For example, Rhizobium, Azotobacter.
• Nitrifying bacteria are those bacteria that those bacteria which convert ammonia to nitrite and nitrite to nitrate. For example, Nitrosomonas, Nitrosococcus, Nitrobacter.
• Denitrifying bacteria are those bacteria that convert nitrates into nitrites and nitrites into free nitrogen. For example, Thiobacillus denitrificans, Micrococcus denitrificans, Pseudomonas aeruginosa.