UNIVERSITY OF INDIANA, BREAH LASARREA bacterium that turns inedible plant parts into ethanol three- to five-times faster than baker’s yeast (Saccharomyces cerevisiae) can fix—or convert—atmospheric nitrogen gas into ammonium, according to a study published today (February 2) in PNAS. The results suggest that elemental nitrogen could one day replace the traditional industrially produced, expensive, and environmentally damaging ammonium added to biofuel reactors as the source of a nutrient that is necessary for the growth of microorganisms that break down plant cellulose into ethanol.
“It was known already that the Zymomonas genome contains all the genes that are needed, but nobody had checked whether they really are able to fix nitrogen,” said Uldis Kalnenieks of the University of Latvia who was not involved in the research. “Yeast, which also can make ethanol, can’t fix nitrogen, so if another ethanol-producing microorganism can, that is an advantage.”
James “Jake” McKinlay of the University of Indiana and his colleagues had previously engineered a different bacterium, Rhodopseudomonas palustris, to fix nitrogen, with the aim of providing naturally produced ammonium to another species of bacteria in the same culture. To their surprise, the control culture of Z. mobilis on its own grew just as well on nitrogen gas as the coculture of Z. mobilis ...
