Nitrogenase artificial activation

Nitrogenase, a bacteria-based enzyme with α₂β₂δ₄ heterooctameric or α₂β₂ heterotetramer composition (Azotobacter vinelandii, V-Fe, Mo-Fe, respectively), has the unique ability to generate ammonia by atmospheric nitrogen fixation. Although these exceptional enzymes have been studied for several decades, only recently researchers found that they are useful for artificial fixation of nitrogen to ammonia by semiconductor NRs nitrogenase hybrids. Photocatalysis and biocatalysis are emerging tools for the generation of clean energy and unique precursors for the pharmaceutical industry.

On one hand, by photocatalysis, light irradiation enables a variety of high energy reactions but usually suffers from low selectivity and low efficiency. On the other hand, enzymes enable stereospecific reactions with low energy barriers and high efficiency, but cofactors are needed for continuous activation. By enabling them both simultaneously, a synergetic effect could be gained that can lead to self-powered systems with high selectivity catalysis and activity. Here we present a method to activate a mutated nitrogenase variant by light-triggered CdS NPs. The effect of the NPs ligands and the redox mediators on the hydrogen and ammonia generation will be presented and discussed.