Kinetics of denitrification by Pseudomonas denitrificans under growth conditions limited by carbon and/or nitrate or nitrite

Kinetic experiments were carried out for a pure culture of Pseudomonas denitrificans to develop a mathematical model that adequately describes denitrification under both carbon and nitrate or nitrite electron acceptor limited conditions. Denitrification was assumed to occur by the consecutive reduction of nitrates to nitrites and then to nitrogen gas without accumulation of intermediate gaseous products. The denitrification kinetics, assuming they are associated with cell growth, could be very well described by using Monod expressions with double substrate limitation (terminal electron acceptor and organic carbon). The kinetic parameters of the model were evaluated exclusively from batch experimental data. The proposed model is able to predict accurately the biomass growth, the nitrate and nitrite reduction rates, as well as the accumulation of nitrite-nitrogen as an intermediate, due to nitrate inhibition on the nitrite reduction rate.