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, N 2 ) and environmental (nitrate and nitrite, NO 3 − and NO 2 − ) sources of N to be utilized in amino acid synthesis in various forms of life, it must first be reduced to ammonia (NH 3 ). The Haber–Bosch process, in which N 2 is reduced to NH 3 at elevated temperature and pressure, represents a major NH 3 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 NH 3 production biotechnologies.