title: [Identification and function test of an alkali-tolerant denitrifying bacterium].
abstract: OBJECTIVE
  We obtained an alkali-tolerant denitrifying bacterium, and determined its denitrifying activity and alkali-tolerance.
  
  
  METHODS
  An alkali-tolerant denitrifying bacterial strain was obtained by isolation and purification. We identified the bacterial strain by morphological observation, physiological test and 16S rRNA analysis. We determined the denitrifying activity and alkali-tolerance by effects of initial nitrate concentration and initial pH on denitrification.
  
  
  RESULTS
  An alkali-tolerant denitrifier strain R9 was isolated from the lab-scale high-rate denitrifying reactor, and it was identified as Diaphorobater nitroreducens. The strain R9 grew heterotrophically with methanol as the electron donor and nitrate as the electron acceptor. The nitrate conversion was 93.25% when strain R9 was cultivated for 288 h with initial nitrate concentration 50 mg/L and initial pH 9.0. The denitrification activity could be inhibited at high nitrate concentration with a half inhibition constant of 202.73 mg N/L. Strain R9 showed a good alkali tolerance with the nitrate removal rate at pH 11.0 remained 86% of that at pH 9.0.
  
  
  CONCLUSIONS
  Strain R9 was identified as Diaphorobater nitroreducens, and it was an alkali-tolerant denitrifying bacterium with optimum pH value of 9.0.
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China. wangru890501@163.com
authors.forename: Ru
authors.initials: R
authors.lastname: Wang
authors.forename: Ping
authors.initials: P
authors.lastname: Zheng
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Hui
authors.initials: H
authors.lastname: Chen
authors.forename: Tingting
authors.initials: T
authors.lastname: Chen
authors.forename: Abbas
authors.initials: A
authors.lastname: Ghulam
mesh_terms: D000468:Alkalies / Q000378:metabolism*; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000378:metabolism*; D058440:Denitrification; D006863:Hydrogen-Ion Concentration; D009566:Nitrates / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D000468:Alkalies; D009566:Nitrates; D009573:Nitrites; D012336:RNA, Ribosomal, 16S