Related Experiment Video
Updated: Aug 14, 2026

Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O
Published on: October 7, 2020
Effect of Medium Composition on the Denitrification of Nitrate by Paracoccus denitrificans
1Institute of Microbiology, Warsaw University, Karowa 18, 00-324 Warsaw, Poland.
Abstract:
The course of denitrification of nitrate in static cultures of Paracoccus denitrificans was studied. Reduction of nitrate to gaseous nitrogen without accumulation of nitrite because of parallel and balanced activities of nitrate and nitrite reductases was observed in nutrient broth. In minimal liquid cultures supplemented with either methanol, acetate, or ethanol as a sole carbon source, substantial amounts of nitrite (up to 70%) accumulated. The reduction in nitrite concentration began just after the transformation of nitrate to nitrite was completed. The addition of some growth factors to minimal media shortened the bacterial biomass doubling time. A correlation coefficient of 0.71 between the doubling time and the amount of accumulated nitrite in cultures was found. My results indicated that the type of denitrification carried out by P. denitrificans is not stable and depends on the nutritional composition of the culture medium.
Related Concept Videos
Overview of Nitrogen Metabolism
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this nitrogen...
Metabolism of Chemolithotrophs
Inorganic Nitrogen Assimilation
Methods of Medium Optimization
Microbes and the Nitrogen Cycle
Designing Growth Media for Bioreactors

