Anammox: Bad luck or the tip of the iceberg
Marc Strous, Ph.D.
Delft University of Technology, The Netherlands
Wednesday, November 3, 1999
3:00 p.m.Pacific Forum
||A. The planctomycete responsible for Anammox has a central membrane
bounded organelle (z), surrounded by a region containing the dense fibrillar nucleoid (n)
and ribosome-like particles (r).
B. On the cell surface, crateriform structures appear
as small dark spots after negative staining."
With the increased use of chemical fertilizers in agriculture, many densely populated
countries face environmental problems associated with high ammonia emissions. The
anaerobic ammonia oxidation (Anammox) process is one of the most innovative technological
advances in the removal of ammonia-nitrogen from wastewater. This new process combines
ammonia and nitrite directly into dinitrogen gas. The theoretical possibility of Anammox
was recognized as early as 1975. However, bacteria capable of Anammox had never been found
and were known as the "lithotrophs missing in nature." Now, we have found this
missing lithotroph and identified it as a new, autotrophic member of the Order
Planctomycetales, one of the major distinct divisions of the bacteria. The new
planctomycete grows extremely slowly, dividing only once every two weeks. Presently, it
cannot be cultivated with conventional microbiological techniques. The identification of
this bacterium as the one responsible for Anammox is an important contribution to the
problem of unculturability. This notion has become central to microbiology since molecular
ecology showed that scientists have so far devoted themselves to only a fraction of the
naturally occurring microorganisms.
enzyme assays and sub-microliter sample preparation for DNA sequencing
Last updated: December 19, 2000