TABLE 3.

Kinetics of ammonia oxidation and oxygen uptake

StrainAmmonia (NH4+)aOxygenReference
Km (μM)Vmax (μmol per mg protein per h)Km (μM)Vmax (μmol per mg protein per h)
AOA
    AR enrichment culture0.61 (0.02)b14c2.01 (0.45)b11.4cThis study
    “Ca. Nitrosopumilus martimus” SCM10.13 (0.04)d243.90 (0.6)d22.552
AOB
    Nitrosomonas europaea C-31 (ATCC 25978)1,30036186129This study
    Nitrosomonas europaea ATCC 19718530122NDND52
    Activated sludge59NDe15.6ND32
  • a The values are given for NH4+ and NH3.

  • b The numbers in parentheses indicate the standard deviations from triplicate experiments.

  • c We assumed that protein content per cell of AOA in AR culture equals that of “Ca. Nitrosopumilus maritimus” (52).

  • d Data from a study by Martens-Habbena et al. (52).

  • e ND, not determined.