Quantification of denitrification by strain T1 during anaerobic degradation of toluene

Strain T1 is a denitrifying bacterium that is capable of toluene degradation under anaerobic conditions. During anaerobic growth on toluene, the specific growth rate of strain T1 was 0.14 h-1. Nitrite accumulated in the medium stoichiometrically with the depletion of nitrate. When nitrate was nearly depleted from the medium nitrite reduction and dinitrogen formation began. A non-kinetic model was formulated that was based on a hypothesis of non-simultaneous nitrate and nitrite reduction, independent of the concentrations of nitrate and nitrite. The model was verified experimentally over a wide range of conditions that included nitrate and nitrite limitation, toluene limitation, and various ratios of nitrate to nitrite. The model and its experimental verification demonstrated that strain T1 reduces nitrate and nitrite non-simultaneously, even if nitrite is initially present in the medium in addition to nitrate.