Enzymatic Bioelectrosynthetic Ammonia Production: Recent Electrochemistry of Nitrogenase, Nitrate Reductase, and Nitrite Reductase

As an essential component of amino acids and nucleic acids, nitrogen (N) is a key element of life. For atmospheric (dinitrogen, N2) and environmental (nitrate and nitrite, NO3− and NO2−) sources of N to be utilized in amino acid synthesis in various forms of life, it must first be reduced to ammonia (NH3). The Haber–Bosch process, in which N2 is reduced to NH3 at elevated temperature and pressure, represents a major NH3 production process that has had a great impact on the agricultural crop industry. This Minireview discusses the recent electrochemistry of three key enzymes of the global biogeochemical N cycle (nitrogenase, nitrate reductase, and nitrite reductase), in view of moving toward the creation of alternative NH3 production biotechnologies. Bioelectrosynthesis: The global biogeochemical N cycle is comprised of seven key steps. This Minireview evaluates recent electrochemical studies of three key enzymes of the nitrogen cycle: nitrogenase, nitrate reductase, and nitrite reductase (see figure).