ATP production during dissimilatory nitrate reduction in Azorhizobium caulinodans IRBG 46

In Azorhizobium caulinodans IRBG 46 grown microaerobically in culture solution with nitrate as sole source of nitrogen, almost all the activity (>95%) of nitrate reductase (NR) was localized in the particulate fraction (P 250), while total activity of nitrite reductase (NiR) was present in the soluble fraction. Membrane-bound NR was found to be dissimilatory type generating ATP, the ATP/2e− ratios for electron transfer from NADH and succinate to NO3− being 1.83 and 1.46, respectively.