Iron–Molybdenum Quantum Dots for Enhancing the Nitrogenase Activity of Nodules

Biological nitrogen fixation is an important part of the global nitrogen cycle. It provides more than half of the nitrogen in the biosphere. Nitrogen-fixing bacteria convert nitrogen in the atmosphere into a form that can be used for plant growth. In this study, we describe the synthesis of a biofriendly nanocomposite (FeMo QDs@GSH) with peroxidase-like activity to perform more efficient nitrogen fixation. The nanocomposite is co-incubated with a symbiotic nitrogen fixation system. When nodules are exposed to FeMo QDs@GSH concentrations greater than 250 mg L–1 at pH 7.0, nitrogenase activity is enhanced, with a maximum increase of 97.31% at 1000 mg L–1. When Azotobacter chroococcum is exposed to FeMo QDs@GSH with a pH of 9.0, there is a smaller increase of 22.89% at 100 mg L–1. At pH 7.0, FeMo QDs@GSH at 100 and 1000 mg L–1 reduced ROS by 21.02 and 32.77%, respectively. Finally, we have shown that the nanocomposite enters symbiotic tissue cells to perform its antioxidative stress function.