title: Characteristics of an aerobic denitrifier that utilizes ammonium and nitrate simultaneously under the oligotrophic niche.
abstract: BACKGROUND
  An aerobic denitrifier was isolated from the Hua-Jia-Chi pond in China and identified as Pseudomonas mendocina 3-7 (Genbank No. HQ285879). This isolated strain could express periplasmic nitrate reductase which is essential for aerobic denitrification occurred when the dissolved oxygen (DO) level maintains at 3-10 mg L(-1).
  
  
  METHODS
  To determine whether the ability of isolated strain is exhibited in the bioremediation of polluted drinking source water, the heterotrophic nitrification and aerobic denitrification characteristics of P. mendocina 3-7 under different cultural conditions such as oxygen level, nitrate and organic concentrations were studied from the nitrogenous balance in the paper.
  
  
  CONCLUSIONS
  By measuring the nitrogen balance in all experiments under different culture conditions, the removal of total organic carbon and ammonium was positively correlated with total nitrogen removal, especially under high substrate level. With substrate concentration decreasing, ammonium and nitrate removal occurred separately, and ammonium was completely utilized first under low substrate concentration. Compared to that under high substrate level, the specific growth rate of P. mendocina 3-7 was not low under the low substrate level and the pollutant removal efficiencies remained high, which implies the stronger nitrogen removal and acclimatization capacities of the strain in oligotrophic niches.
authors.affiliation: Department of Environmental Engineering, Zhejiang University, No.866 Yuhangtang Road, Hangzhou 310058, People's Republic of China. felix79cn@hotmail.com
authors.forename: Liang
authors.initials: L
authors.lastname: Zhu
authors.forename: Wei
authors.initials: W
authors.lastname: Ding
authors.forename: Li-Juan
authors.initials: LJ
authors.lastname: Feng
authors.forename: Xin
authors.initials: X
authors.lastname: Dai
authors.forename: Xiang-Yang
authors.initials: XY
authors.lastname: Xu
mesh_terms: D000332:Aerobiosis; D000641:Ammonia / Q000378:metabolism*; D002681:China; D058440:Denitrification; D050901:Nitrate Reductase / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism*; D009574:Nitro Compounds / Q000378:metabolism; D010100:Oxygen / Q000032:analysis / Q000378:metabolism; D019897:Periplasm / Q000201:enzymology; D061005:Ponds / Q000382:microbiology; D044203:Pseudomonas mendocina / Q000378:metabolism*
chemical_list: D009566:Nitrates; D009574:Nitro Compounds; D000641:Ammonia; D050901:Nitrate Reductase; D010100:Oxygen