Abstract
The growth kinetics of NH4+-oxidizing bacteria and NO2--oxidizing bacteria were studied using the indirect immunofluorescent counting method. In the case of NH4+-oxidizing bacteria, the maximum specific growth rate (μmax) was 0.58 day-1 and the half saturation constant (Kg) was 200μM NH4+. Maximum specific activity (Amax) during the exponential growth phase was 6.6×10-5nmol/cell/day. From the relationship between the specific growth rate and the specific activity, the maximum growth yield (Ymax) and maintenance coefficient (m) were calculated. Ymax was 1.0×104cells/nmol NH4+ and m was 1.1×10-5 nmol/cell/day. The maintenance coefficient was about 17% of Amax. In the case of NO2--oxidizing bacteria, μmax, Kg and Amax were 0.81 Day-1, 15μM and 2.8×10-4nmol/cell/day, respectively. Ymax and m could not be calculated, since the maintenance coefficient became negative. From these results, the growth kinetics of nitrifying bacteria were discussed.
