Nitrate removal by Fe-dependent denitrification

The traditional biological nitrogen removal utilizes heterotrophic denitrifying bacteria to reduce nitrate to nitrogen, through the nitrification and denitrification stages, which needs organic carbon source as the electron donor. However, several strains of Fe(II)-dependent denitrifying bacteria have been isolated in recent years, which introduced a brand-new concept and mentality for the biological nitrogen removal. It is a recent discovery of microbial metabolism that microorganisms utilize NO₃^- as electron acceptor and Fe or Fe²⁺ as electron donor and get energy through the biochemical reaction for growth. In this paper, the characteristics and mechanisms of Fe(II)-dependent autotrophic denitrifying bacteria were reviewed, and prospects of these bacteria were also discussed.