The Respiratory Way without Microbial Growth of Paracoccus denitrificans

This study elucidates the effects of Carbon/Nitrogen (C/N) ratios on the respiratory behavior of Paracoccus denitrificans PD1222, a microorganism noted for its metabolic adaptability. We explored its ability to undergo dissimilative denitrification, a less understood process where energy is harnessed from nutrient consumption without resultant growth. By manipulating the C/N ratios and available nitrogen sources in our experimental design, we were able to demonstrate significant shifts in P. denitrificans metabolic behavior. At a C/N ratio of 1.34, with nitrate as the sole nitrogen source, dissimilative denitrification occurred with no observable increase in biomass. Succinate, the provided carbon source, was quickly metabolized without contributing to cell growth. Our results contribute to the understanding of environmental microbiology, specifically denitrification processes, and indicate P. denitrificans’s potential for wastewater treatment scenarios, where pollutant consumption without biomass proliferation is desired.