Diazotrophic bacteria play an essential geobiochemical role fixing atmospheric N₂ into ammonia, a process called biological nitrogen fixation (BNF). This process introduces nitrogen into biological systems, where it is present in amino acids, proteins, nucleic acids, and countless organic molecules. Diazotrophs rely on nitrogenase to obtain their fixed nitrogen. Nitrogenase is a complex enzymatic system composed of two proteins that carry three different metal cofactors, in which electron transfer and N₂ reduction catalysis occur. Two of these metal cofactors are unique to nitrogenase, and their complex biosynthetic pathways have no parallel in nature.

As a result, exporting a functional nitrogenase to a non-diazotrophic organism is a mayor endeavor that, although already reported with a number of prokaryotes, still remains a feat to be achieved with eukaryotic systems, such as plants. Engineering crops to endow them with BNF capabilities is of major biotechnological interest.

Worldwide food supplies are endangered by a worrisome number of factors, including climate change and the increasing costs associated to food production. The Haber-Bosch industrial process was key for human prosperity during the past 100 years, as it provided the nitrogen fertilizers that dramatically increased agricultural yields to meet the demands of an ever increasing population. However, current costs for today’s fertilizer-dependent agriculture, and the associated environmental harm, are untenable. There are increasing concerns that a potential reduction of global agriculture production might threaten human communities with economic limitations. Among these, there is special concern about sub-Saharan Africa. The Bill and Melinda Gates Foundation has addressed these challenges through funding social, economical and research projects to alleviate these threats.

The BNF-Cereals project was proposed as a high-risk, long-term research to genetically engineer cereals with the capability of fixing their own nitrogen. Fixed nitrogen is the most important limiting factor and the highest cost in crop production. BNF-Cereals proposes to engineer nitrogenase biosynthesis and function, which is naturally present in diazotrophic bacteria, in plant cell organelles where it would supply the fixed-nitrogen that crops need.