Effect of carbon source, C/N ratio, nitrate and dissolved oxygen concentration on nitrite and ammonium production from denitrification process by Pseudomonasstutzeri D6

► Pseudomonasstutzeri D6, with good denitrifying ability, was isolated from activated sludge. ► Strain D6 was used to study NO2- and NH4+ production from denitrification processes. ► Poor/insufficient C source was prone to produce NO2- and NH4+ during denitrification. ► Low oxygen consumption rate was apt to produce NO2- and NH4+ during denitrification. ► NO2- and NH4+ production was slightly influenced by nitrate during denitrification.