© H. Raguet/CNRS Photothèque At the Genoscope, DNA sequences are assembled. Each red and green box corresponds to a sequence.
© H. Raguet/CNRS Photothèque
At the Genoscope, DNA sequences are assembled. Each red and green box corresponds to a sequence.
The genome of Kuenenia stuttgartiensis has been sequenced, quite an achievement for the Genoscope's1 Metabolic Genomic team2 and their collaborators from the Universities of Nijmegen (
Why? Because Kuenenia stuttgartiensis is the prototype of the anammox– anaerobic ammonium oxidation –bacteria, which transform ammonium into nitrogen in the absence of oxygen. Their utilization for ammonium removal from wastewater, in comparison with the conventional method of nitrification/denitrification, could present several advantages. The procedure is simpler, quicker, and the costs are cut by 90%, notably by an economy of energy. “As the anammox reaction is done under anaerobic conditions,” explains Le Paslier, “the supply of oxygen to the basin–which is very expensive–can be reduced. It's even better if there is no oxygen at all.” An experimental system is currently being tested in
Like the majority of bacteria from the environment, Kuenenia could not be isolated. The French team extracted DNA from a complex community of bacteria cultivated for one year in a bioreactor in the
The genome sequence has revealed interesting features. For example, it carries the genetic blueprint of hydrazine metabolism and ladderane biosynthesis. These lipids compose the membrane of the anammoxosomes. This bacterium organelle confines highly toxic anammox reaction intermediates such as nitric oxide and hydrazine (rocket fuel).
And, last but not least, the DNA analysis has settled the controversy surrounding the evolutionary origin of Planctomycetes. This poorly understood group, that includes the anammox bacteria, shares a common ancestor with the intracellular parasite Chlamydiae.
1. The French national center dedicated to sequencing.
2. Génomique métabolique (CNRS / Université d'Evry / Consortium national de recherche en génomique joint lab).
Denis Le Paslier