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November 27th, 2018 / Genetic Literacy Project, US

At the turn of the previous century, German scientists Fritz Haber and Carl Bosch got all the credit for finding a way to convert atmospheric nitrogen (in its very stable N2 form) into a charged ion that could be “fixed” or applied as a chemical fertilizer. Both eventually were awarded the Nobel Prize in chemistry for their efforts.

At almost exactly the same time, Dutch microbiologist Martinus Beijerinck discovered how certain bacteria do the same thing naturally.

Scientists are now looking at genetics to see if they can take the ability of the bacteria Beijerinck studied, which even today only “fix” nitrogen in certain legumes, like peanuts, soybeans and peas (hence the need for applied nitrogen in crops like wheat, corn, oats or rice). If they can recreate the fixing process in other cells, then those cells could literally create their own fertilizer as they grow and propagate.

That won’t be easy. There are at least 20 genes involved in nitrogen fixation, and while the Haber-Bosch process takes a great deal of energy, so does “natural” fixation—about 16 moles (the standard unit comparing units of atoms, molecules, and the like) of adenosine triphosphate (ATP), the energy-containing molecule in all cells, are needed to reduce one mole of nitrogen to nitrate. A successful fixation would need to harness cellular signaling, receptors and target genes that are precisely regulated and respond even to small changes in environmental conditions to, in some cases, recreate the cycles and reactions that result in nitrogen fixing.

But a number of efforts to genetically fix nitrogen are starting to pay off, thanks to more precise identification of DNA sequences and better gene-editing techniques. Breeding (in the biological sense) has helped, too. Read more