A colorimetric method to measure in vitro nitrogenase functionality for engineering nitrogen fixation.

Biological nitrogen fixation (BNF) is the reduction of N into NH in a group of prokaryotes by an extremely O-sensitive protein complex called nitrogenase. Transfer of the BNF pathway directly into plants, rather than by association with microorganisms, could generate crops that are less dependent on synthetic nitrogen fertilizers and increase agricultural productivity and sustainability. In the laboratory, nitrogenase activity is commonly determined by measuring ethylene produced from the nitrogenase-dependent reduction of acetylene (ARA) using a gas chromatograph.