Kraft B, Tegetmeyer HE, Sharma R, Klotz MG, Ferdelman TG, Hettich RL, et al. Denitrification−ecological niches, competition and survival. Tiedje JM, Sexstone AJ, Myrold DD, Robinson JA. Capacity for denitrification and reduction of nitrate to ammonia in a coastal marine sediment. The influence of nitrate concentration upon the end-products of nitrate dissimilation by bacteria in anaerobic salt-marsh sediment. Nitrite reduction to ammonia by fermentative bacteria: a short circuit in the biological nitrogen cycle. nov sp nov., a novel obligately anaerobic sulfur- and dissimilatory nitrate-reducing bacterium from a full-scale sulfide-removing bioreactor. Sorokin DY, Foti M, Tindall BJ, Muyzer G. Denitrification versus respiratory ammonification: environmental controls of two competing dissimilatory NO 3 -/NO 2 - reduction pathways in Shewanella loihica strain PV-4. Yoon S, Cruz-Garcia C, Sanford R, Ritalahti KM, Loffler FE. Vertical activity distribution of dissimilatory nitrate reduction in coastal marine sediments. Refined NrfA phylogeny improves PCR-based nrfA gene detection. Welsh A, Chee-Sanford JC, Connor LM, Loffler FE, Sanford RA. Diversity and evolution of bioenergetic systems involved in microbial nitrogen compound transformations. Microbial nitrate respiration - genes, enzymes and environmental distribution. Our results indicate that DNRA catalyzed by octaheme nitrite reductases is a metabolic feature of many Geobacteraceae, representing important community members in various anaerobic systems, such as rice paddy soil and wastewater treatment facilities. Thus, the Nap-TaNiR complex represents a novel type of highly functional DNRA module. It presumably interacts with two ferredoxin subunits (NapGH) that donate electrons from the menaquinol pool to the periplasmic nitrate reductase (NapAB) and TaNiR. We purified this octaheme cytochrome c protein (TaNiR), which is a highly active dissimilatory ammonifying nitrite reductase loosely associated with the cytoplasmic membrane. Instead, we identified a locus encoding a periplasmic nitrate reductase immediately followed by an octaheme cytochrome c that is conserved in many Geobacteraceae species. The genome of G1 does not encode the classical ammonifying modules NrfAH/NrfABCD. ammonificans is an extremely specialized ammonifier, actively growing only with acetate as e-donor and carbon source and nitrate as e-acceptor, but H 2 can be used as an additional e-donor. This allowed purification of this DNRA organism from competing denitrifiers. Here, we isolated and characterized the new species Trichlorobacter ammonificans strain G1 using a combination of low redox potential and copper-depleted conditions. Several ammonifying Trichlorobacter strains (former Geobacter) were previously enriched from activated sludge in nitrate-limited chemostats with acetate as electron ( e) donor, demonstrating their presence in these systems. Dissimilatory nitrate reduction to ammonia (DNRA) is a common biochemical process in the nitrogen cycle in natural and man-made habitats, but its significance in wastewater treatment plants is not well understood.
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