Nitrite, an Electron Donor for Anoxygenic Photosynthesis
Benjamin M. Griffin,*
Joachim Schott,
Bernhard Schink
We report a previously unknown process in which anoxygenic phototrophic bacteria use nitrite as an electron donor for photosynthesis. We isolated a purple sulfur bacterium 98% identical to Thiocapsa species that stoichiometrically oxidizes nitrite to nitrate in the light. Growth and nitrate production strictly depended on both light and nitrite. This is the first known microbial mechanism for the stoichiometric oxidation of nitrite to nitrate in the absence of oxygen and the only known photosynthetic oxidation in the nitrogen cycle. This work demonstrates nitrite as the highest-potential electron donor for anoxygenic photosynthesis known so far.
Department for Biology, Universität Konstanz, D-78457 Konstanz, Germany.
* Present address: Institute for Genomic Biology, University of Illinois, Urbana, IL 61801, USA. To whom correspondence should be addressed. E-mail: griff113{at}uiuc.edu
