Aerobic denitrification: A review of important advances of the last 30 years

Understanding aerobic denitrification has become an important focus of environmental microbiology. Aerobic denitrification can be performed by various genera of microorganisms and describes the use of nitrate (NO (3) (-) ) as oxidizing agents under an aerobic atmosphere. Isolation of aerobic denitrifiers, enzymes involved in aerobic denitrifiers, phylogenetic distribution of aerobic denitrifiers, factors affecting the performance of aerobic denitrifiers, attempts of applications and possible future trends are depicted. The periplasmic nitrate reductase is vital for aerobic denitrifiers and NapA gene may be the proof of aerobic denitrification. Phylogenetic analysis revealed that aerobic denitrifiers mainly belong to alpha-, beta- and gamma-Proteobacteria. Aerobic denitrifiers tend to work efficiently at 25 similar to 37A degrees C and pH 7 similar to 8, when dissolved oxygen concentration is 3 similar to 5 mg/L and C/N load ratio is 5 similar to 10. In addition, recent progresses and applications on aerobic denitrifiers are described, including single aerobic reactors, sequencing batch reactor and biofilm reactors. The review attempts to shed light on the fundamental understanding in aerobic denitrification.