April 10, 2012
The nitrogen busters: USU team learning how nature ‘fixes’ crucial element for life
(Brian Maffly, Salt Lake Tribune) — Life on Earth is literally swimming in a sea of nitrogen, which makes up 80 percent of the atmosphere. But in one of nature’s great ironies, the essential element is not available in an atmospheric form that plants and animals can use.
This is because the atoms in dinitrogen molecules, N2, are locked together in a triple chemical bond — the toughest nut in chemistry — and it takes the work of enzymes to sever nitrogen atoms and recombine with hydrogen in a form plants can use: ammonia, or NH3.
“This is green chemistry. We are starting to illuminate for the first time how this enzyme can do it in mild conditions,” said researcher Lance Seefeldt, a USU professor in the department of chemistry and biochemisty. He is a senior co-author on a paper published last month describing a method for identifying key steps in natural nitrogen reduction.
Seefeldt estimates that 2 percent of the world’s fossil-fuel consumption is devoted to nitrogen reduction using the existing Haber-Bosch process. Replacing this process with one that replicates nature will mean far fewer resources are burned to make fertilizer.
“The agronomic and economic and, indeed, human significance of this process can be appreciated from the perspective that the ‘fixed nitrogen’ of ammonia, along with water, are generally the two limiting nutrients in crop production, and that the lives of about two-thirds of Earth’s population depend on the ammonia produced by nitrogenase,” said co-author Brian Hoffman, professor of chemistry at Northwestern University.
Nitrogenase are the bacterial enzymes that have evolved to break down nitrogen. Without them, life would not have prospered on Earth.
“Nitrogen is essential to our proteins, our DNA. Every living thing needs it. Where we get that nitrogen is the challenge. Nitrogen is the limiting element,” Seefeldt said. For his work in nitrogenase, Seefeldt was honored last week as the recipient of the 2012 D. Wynne Thorne Career Research Award, USU’s highest research prize.
“It is fair to say that professor Seefeldt is the most influential thinker in the area of nitrogenase enzymology in the world today,” said Southern Methodist University provost Paul Ludden, an expert in microbial biochemistry. “Through brilliant experimental design, professor Seefeldt and his collaborators have been successful where others have failed. I have heard the word ‘fearless’ used to describe professor Seefeldt, and this is quite an appropriate attribution.” More…Posted by: psilberman