In order to study the effect of nitrite and nitrate on the performance of microbial fuel cell, a system combining an anaerobic fluidized bed (AFB) and a microbial fuel cell (MFC) was employed for high-strength nitrogen-containing synthetic wastewater treatment. Before this study, the AFB-MFC had been used to treat high-strength organic wastewater for about one year in a continuous flow mode. Th...

Lakes can be important sources of the potent greenhouse gas nitrous oxide (N2O) to atmosphere, but what extent abiotic processes may contribute lacustrine N2O production remains uncertain. We assessed pathways and reduction in water column meromictic iron-rich Lake La Cruz, Spain, including chemodenitrification-induced formation via reaction reactive nitrogen (N) (e.g., NO 2 − $$ {\mathrm{NO}}_...

Propionibacterium acnes P13 was isolated from human feces. The bacterium produced a particulate nitrate reductase and a soluble nitrite reductase when grown with nitrate or nitrite. Reduced viologen dyes were the preferred electron donors for both enzymes. Nitrous oxide reductase was never detected. Specific growth rates were increased by nitrate during growth in batch culture. Culture pH stron...

Denitrification and anaerobic ammonium oxidation (anammox) are the key processes of nitrogen removal in aquaculture pond sediment. However, reaction characteristics remain unclear. In this study, considering sediment conventional freshwater fishponds as object, we set optimal conditions organic carbon, temperature, total nitrates for denitrification anammox. We found that abundance diversity de...

The process of nitrate reduction via nitrite controls the fate and bioavailability of mineral nitrogen within ecosystems; i.e., whether it is retained as ammonium (ammonification) or lost as nitrous oxide or dinitrogen (denitrification). Here, we present experimental evidence for a novel pathway of microbial nitrate reduction, the reverse hydroxylamine:ubiquinone reductase module (reverse-HURM)...

The pathway of anaerobic reduction of nitrite to nitrogen gas (N2) by cell suspensions of the denitrifier, Pseudomonas aeruginosa, was studied using the techniques of gas chromatography and mass spectrometry. While release of nitrous oxide (N2O) is not normally detected during the reduction of nitrite to N2 by this organism, 15N from [15N]nitrite nevertheless can be trapped quantitatively as 15...

Methane can be used as an alternative carbon source in biological denitrification because it is nontoxic, widely available and relatively inexpensive. A microbial consortium involved in methane oxidation coupled to denitrification (MOD) was enriched with nitrite and nitrate as electron acceptors under micro-aerobic conditions. The 16S rRNA gene combined with pmoA phylogeny of methanotrophs and ...

Measurements show that anaerobic ammonium oxidation with nitrite (anammox) is a major pathway of fixed nitrogen removal in the anoxic zones of the open ocean. Anammox requires a source of ammonium, which under anoxic conditions could be supplied by the breakdown of sinking organic matter via heterotrophic denitrification. However, at many locations where anammox is measured, denitrification rat...

Microorganisms are the most abundant lifeform on Earth, mediating global fluxes of matter and energy. Over the past decade, high-throughput molecular techniques generating multiomic sequence information (DNA, mRNA, and protein) have transformed our perception of this microcosmos, conceptually linking microorganisms at the individual, population, and community levels to a wide range of ecosystem...

Nitrite-dependent anaerobic methane oxidation (n-damo), which couples the anaerobic oxidation of methane to denitrification, is a recently discovered process mediated by "Candidatus Methylomirabilis oxyfera." M. oxyfera is affiliated with the "NC10" phylum, a phylum having no members in pure culture. Based on the isotopic labeling experiments, it is hypothesized that M. oxyfera has an unusual i...