1, The nitrogenase complex in certain bacteria(( diazotrophs,;圆氮生勒 catalyzes the conversion of N, to NH Cyanobacteria (photosynthetic) and rhizobia (symbiont) can fix N, into NH3 The reduction of n to nh, is thermodynamically favorable 3H 2NH2 4G0=-33. 5kJ/mol for the tuple bond in N, is 942 \mo ergy But kinetically unfavorable: the bond e1. The nitrogenase complex in certain bacteria (diazotrophs,固氮生物) catalyzes the conversion of N2 to NH3 • Cyanobacteria (photosynthetic) and rhizobia (symbiont) can fix N2 into NH3 . • The reduction of N2 to NH3 is thermodynamically favorable : • N2 + 3H2 2NH3 G` o=-33.5kJ/mol • But kinetically unfavorable: the bond energy for the triple bond in N2 is 942 kJ/mol