Kinetic characterisation of an enriched Nitrospira culture with comparison to Nitrobacter.
Nitrospira and Nitrobacter are nitrite-oxidising bacteria commonly identified in nitrogen removal wastewater treatment plants. Little is known about the growth parameters of Nitrospira or the effects of environmental conditions or inhibitory compounds on Nitrospira activity. These bacterial properties were investigated using an enriched Nitrospira culture and an enriched Nitrobacter culture or Nitrobacter literature values. Compared to Nitrobacter, Nitrospira was found to have a comparable optimal pH range (8.0-8.3); similar normalised activity-temperature relationship (0.44e(0.055(T-15))) for temperatures between 15 and 30 degrees C and a similar oxygen half-saturation constant, K(O) (0.54+/-0.14 mgL(-1)). The major differences identified were that Nitrospira had a lower nitrite half-saturation constant, K(S) (0.9+/-0.07 mgNO(2)-NL(-1)); lower inhibition threshold concentrations for free ammonia (between 0.04 and 0.08 mg NH(3)-NL(-1)) and free nitrous acid (less than 0.03 mg HNO(2)-NL(-1)) and a higher yield (0.15+/-0.04 g VSS g N(-1)). Therefore, Nitrospira is more likely to dominate nitrite oxidation under conditions with low ammonium and nitrite concentrations, which would provide an advantage to them due to their lower K(S) value while avoiding any free ammonia or free nitrous acid inhibition.
Blackburne
Richard
R
Advanced Wastewater Management Centre, The University of Queensland, Brisbane 4072, Australia.
Vadivelu
Vel M
VM
Yuan
Zhiguo
Z
Keller
Jürg
J
D001419:Bacteria / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D018929:Cell Culture Techniques / Q000379:methods*; D003470:Culture Media / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009573:Nitrites / Q000378:metabolism; D009576:Nitrobacter / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D009608:Nitrous Acid / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D013696:Temperature
D003470:Culture Media; D009573:Nitrites; D002245:Carbon Dioxide; D010100:Oxygen; D009608:Nitrous Acid