Nitrite-driven anaerobic methane oxidation by oxygenic bacteria.

Only three biological pathways are known to produce oxygen: photosynthesis, chlorate respiration and the detoxification of reactive oxygen species. Here we present evidence for a fourth pathway, possibly of considerable geochemical and evolutionary importance. The pathway was discovered after metagenomic sequencing of an enrichment culture that couples anaerobic oxidation of methane with the reduction of nitrite to dinitrogen.

Enrichment and molecular detection of denitrifying methanotrophic bacteria of the NC10 phylum.

Anaerobic methane oxidation coupled to denitrification was recently assigned to bacteria belonging to the uncultured phylum NC10. In this study, we incubated sediment from a eutrophic ditch harboring a diverse community of NC10 bacteria in a bioreactor with a constant supply of methane and nitrite. After 6 months, fluorescence in situ hybridization showed that NC10 bacteria dominated the resulting population.

Denitrifying bacteria anaerobically oxidize methane in the absence of Archaea.

Recently, a microbial consortium was shown to couple the anaerobic oxidation of methane to denitrification, predominantly in the form of nitrite reduction to dinitrogen gas. This consortium was dominated by bacteria of an as yet uncharacterized division and archaea of the order Methanosarcinales. The present manuscript reports on the upscaling of the enrichment culture, and addresses the role of the archaea in methane oxidation.

A microbial consortium couples anaerobic methane oxidation to denitrification.

Modern agriculture has accelerated biological methane and nitrogen cycling on a global scale. Freshwater sediments often receive increased downward fluxes of nitrate from agricultural runoff and upward fluxes of methane generated by anaerobic decomposition. In theory, prokaryotes should be capable of using nitrate to oxidize methane anaerobically, but such organisms have neither been observed in nature nor isolated in the laboratory.

Deciphering the evolution and metabolism of an anammox bacterium from a community genome.

Anaerobic ammonium oxidation (anammox) has become a main focus in oceanography and wastewater treatment. It is also the nitrogen cycle's major remaining biochemical enigma. Among its features, the occurrence of hydrazine as a free intermediate of catabolism, the biosynthesis of ladderane lipids and the role of cytoplasm differentiation are unique in biology.

Global impact and application of the anaerobic ammonium-oxidizing (anammox) bacteria.

In the anaerobic ammonium oxidation (anammox) process, ammonia is oxidized with nitrite as primary electron acceptor under strictly anoxic conditions. The reaction is catalysed by a specialized group of planctomycete-like bacteria. These anammox bacteria use a complex reaction mechanism involving hydrazine as an intermediate.

Anammox organisms: enrichment, cultivation, and environmental analysis.

Anaerobic ammonium oxidation (anammox) is the microbial oxidation of ammonium with nitrite to dinitrogen gas under strict anoxic conditions mediated by planctomycete-like bacteria. Anammox is not only important in the oceanic nitrogen cycle, but can also contribute substantially to nitrogen removal in municipal and industrial wastewater treatment. This chapter addresses the enrichment and cultivation of anammox bacteria in a sequencing batch reactor (SBR) and a gas lift reactor.

Propionate oxidation by and methanol inhibition of anaerobic ammonium-oxidizing bacteria.

Anaerobic ammonium oxidation (anammox) is a recently discovered microbial pathway and a cost-effective way to remove ammonium from wastewater. Anammox bacteria have been described as obligate chemolithoautotrophs. However, many chemolithoautotrophs (i.

Complete conversion of nitrate into dinitrogen gas in co-cultures of denitrifying bacteria.

In the past 10 years many molecular aspects of microbial nitrate reduction have been elucidated, but the ecophysiology of this process is hardly understood. In this contribution, our efforts to study the complex microbial communities and interactions involved in the reduction of nitrate to dinitrogen gas are summarized. The initial work concentrated on emission of the greenhouse gas nitrous oxide during incomplete denitrification by Alcaligenes faecalis.

1994-2004: 10 years of research on the anaerobic oxidation of ammonium.

The obligately anaerobic ammonium oxidation (anammox) reaction with nitrite as primary electron acceptor is catalysed by the planctomycete-like bacteria Brocadia anammoxidans, Kuenenia stuttgartiensis and Scalindua sorokinii. The anammox bacteria use a complex reaction mechanism involving hydrazine as an intermediate. They have a unique prokaryotic organelle, the anammoxosome, surrounded by ladderane lipids, which exclusively contains the hydrazine oxidoreductase as the major protein to combine nitrite and ammonia in a one-to-one fashion.

Implementation of the Anammox process for improved nitrogen removal.

Stringent standards for nitrogen discharge necessitate the implementation of new systems for the sustainable removal of ammonium from wastewater. One of such systems is based on the process of anaerobic ammonium oxidation (Anammox), which is a new powerful tool especially for strong nitrogenous wastewaters. In this study, the Anammox process performance was tested with synthetic wastewater in a completely stirred tank reactor (CSTR).

Candidatus "Scalindua brodae", sp. nov., Candidatus "Scalindua wagneri", sp. nov., two new species of anaerobic ammonium oxidizing bacteria.

Anaerobic ammonium oxidation (anammox) is both a promising process in wastewater treatment and a long overlooked microbial physiology that can contribute significantly to biological nitrogen cycling in the world's oceans. Anammox is mediated by a monophyletic group of bacteria that branches deeply in the Planctomycetales. Here we describe a new genus and species of anaerobic ammonium oxidizing planctomycetes, discovered in a wastewater treatment plant (wwtp) treating landfill leachate in Pitsea, UK.

Anaerobic ammonium oxidation by marine and freshwater planctomycete-like bacteria.

Recently, two fresh water species, " Candidatus Brocadia anammoxidans" and " Candidatus Kuenenia stuttgartiensis", and one marine species, " Candidatus Scalindua sorokinii", of planctomycete anammox bacteria have been identified. " Candidatus Scalindua sorokinii" was discovered in the Black Sea, and contributed substantially to the loss of fixed nitrogen. All three species contain a unique organelle--the anammoxosome--in their cytoplasm.

Anaerobic ammonia oxidation in the presence of nitrogen oxides (NO(x)) by two different lithotrophs.

The anaerobic ammonia-oxidizing activity of the planctomycete Candidatus "Brocadia anammoxidans" was not inhibited by NO concentrations up to 600 ppm and NO2 concentrations up to 100 ppm. B. anammoxidans was able to convert (detoxify) NO, which might explain the high NO tolerance of this organism.

Missing lithotroph identified as new planctomycete.

With the increased use of chemical fertilizers in agriculture, many densely populated countries face environmental problems associated with high ammonia emissions. The process of anaerobic ammonia oxidation ('anammox') is one of the most innovative technological advances in the removal of ammonia nitrogen from waste water. This new process combines ammonia and nitrite directly into dinitrogen gas.

The anaerobic oxidation of ammonium.

From recent research it has become clear that at least two different possibilities for anaerobic ammonium oxidation exist in nature. 'Aerobic' ammonium oxidizers like Nitrosomonas eutropha were observed to reduce nitrite or nitrogen dioxide with hydroxylamine or ammonium as electron donor under anoxic conditions. The maximum rate for anaerobic ammonium oxidation was about 2 nmol NH4+ min-1 (mg protein)-1 using nitrogen dioxide as electron acceptor.