Figure 2.

Plant growth-promoting rhizobacteria’s molecular N₂ fixing mechanism. The nitrogen fixation process is carried out by the nitrogenase enzyme complex, which comprises dinitrogenase reductase and dinitrogenase. Dinitrogenase reductase produces electrons, which dinitrogenase uses to convert N₂ to NH₃. Because the enzyme complex can attach to O₂ and become inactive, oxygen is a powerful inhibitor. Bacterial leghemoglobin, on the other hand, has a higher affinity for oxygen and hence binds to free oxygen more effectively. As a result, the presence of leghemoglobin protects the nitrogenase enzyme complex from oxygen, keeping it active [16].