section_path: Mechanism/Microbiological considerations
section_name: Microbiological considerations
paragraph_text: Microbiological considerations
  
  Two sets of enzymatic reactions are highly relevant to the efficiency of nitrogen-based fertilizers.
  
  The first is the hydrolysis (reaction with water) of urea (CO(NH)). Many soil bacteria possess the enzyme urease, which catalyzes the conversion of urea to ammonium ion (NH + 4) and bicarbonate ion (HCO − 3).
  
  Ammonia-oxidizing bacteria (AOB), such as species of Nitrosomonas, oxidize ammonia (NH) to nitrite (NO − 2), a process termed nitrification. Nitrite-oxidizing bacteria, especially Nitrobacter, oxidize nitrite (NO − 2) to nitrate (NO − 3), which is extremely soluble and mobile and is a major cause of eutrophication and algal bloom.