Denitrifying bacteria

Nitrite production via denitrification has been regarded as a key approach for survival of anaerobic ammonium oxidation (anammox) bacteria. Despite the important carbon substrate, little is known about the role of differential genes expression and extracellular metabolite regulation among diverse microbial communities. In this study, a novel alternating feast-famine strategy was proposed and demonstrated to efficiently accumulate nitrite in a low-nitrogen loading rate (NLR) (0.2∼0.8 kg N/m3 /d) denitrification system...

Although aerobic composting is usually utilized in livestock manure disposal, the emission of odorous gases from compost not only induces harm to the human body and the environment, but also causes loss of nitrogen, sulfur, and other essential elements, resulting in a decline in product quality. The impact of biotrickling filter (BTF) and insertion of carbon-based microbial agent (CBMA) on compost maturation, odor emissions, and microbial population during the chicken manure composting were assessed in the current experiment...

Methane emissions present a significant environmental challenge in both natural and engineered aquatic environments. Denitrifying anaerobic methane oxidation (N-DAMO) has the potential for application in wastewater treatment plants. However, our understanding of the N-DAMO process is primarily based on studies conducted on environmental samples or enrichment cultures using metagenomic approaches. To gain deeper insights into N-DAMO, we used antimicrobial compounds to study the function and physiology of ' Candidatus Methanoperedens nitroreducens' and ' Candidatus Methylomirabilis oxyfera' in N-DAMO enrichment cultures...

Chlorella sp. and Navicula sp. were separately used to construct an algal-bacterial symbiotic system in two identical sequencing batch reactors (R1 and R2 ) to explore the influence of algal species differences on nitrite accumulation. The Navicula-bacterial symbiotic system showed a higher nitrite accumulation efficiency of 85% and a stronger resistance to ammonia load. It secreted twice as many extracellular polymeric substances than the Chlorella-bacterial symbiotic system. Nitrospira and SM1A02 were the dominant functional genera of nitrite-oxidizing bacteria in R1 ...

This study describes the seasonal course of denitrifying and nitrate-reducing bacteria in a dimictic mesotrophic lake (Lake Scharmützelsee, Brandenburg, Germany) within a three-year period from 2011 to 2013. The bacterial cell numbers were quantified by the fluorescence microscopy, most probable number (MPN) and PCR-dependent quantification of the chromosomal 16S rDNA and of the nirS and nirK gene copy number. The highest seasonal differences (up to three orders of magnitudes) have been measured using MPN in the epilimnion...

The low-temperature environment significantly inhibits the growth and metabolism of denitrifying bacteria, leading to an excessive concentration of ammonia nitrogen and total nitrogen in sewage treatment plants during the cold season. In this study, an efficient denitrifying strain of heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria named HS2 was isolated and screened from industrial sewage of a chemical factory in Inner Mongolia at 8 °C. The strain was confirmed to be Achromobacter spiritinus , a colorless rod-shaped bacterium...

N2 O-reducing bacteria have been examined and harnessed to develop technologies that reduce the emission of N2 O, a greenhouse gas produced by biological nitrogen removal. Recent investigations using omics and physiological activity approaches have revealed the ecophysiologies of these bacteria during nitrogen removal. Nevertheless, their involvement in‍ ‍anammox processes remain unclear. Therefore, the present study investigated the identity, genetic potential, and activity‍ ‍of N2 O reducers in an anammox reactor...

The emerging nitrogen removal process known as CANDAN (Complete Ammonium and Nitrate removal via Denitratation-Anammox over Nitrite) has been developed in Sequencing Batch Reactors (SBRs). Yet, starting up and maintaining stability in continuous-flow reactors remain challenging. This study explores the feasibility of transitioning the CANDAN process from an anammox-dominated process by introducing appropriate external organics to facilitate indigenous nitrite-producing denitrification community in an Upflow Anaerobic Sludge Blanket (UASB) reactor...

The stability of the two-stage partial nitrification-anammox (PN/A) system was compromised by the inappropriate conversion of insoluble organic matter. In response, a sludge redistribution strategy was implemented. Through the redistribution of PN sludge and anammox sludge in the two-stage PN/A system, a transition was made to the Anammox-single stage PN/A (A-PN/A) system. This specific functional reorganization, facilitated by the rapid reorganization of microbial communities, has the potential to significantly decrease the current risk of suppression...

It is challenging to differentiate bacteria residing in the same habitat by direct observation. This difficulty impedes the harvest, application and manipulation of functional bacteria in environmental engineering. In this study, we developed a novel method for rapid differentiation of living denitrifying bacteria based on derivative synchronous fluorescence spectroscopy, as exemplified by three heterotrophic nitrification-aerobic denitrification bacteria having the maximum nitrogen removal efficiencies greater than 90%...

The high organic matter in river sediment primarily induces black and odorous rebound. Traditional humic-reducing bacteria demonstrate relatively single metabolic functions and restrain the remediation within complex sediment environments. In addition, Ca(NO3 )2 is commonly utilized in synergistic with bioremediation to improve the reducing environment of sediments. In this study, a multifunctional bacterial community with humic reduction-denitrification coupled bacteria was domesticated by the step-feeding strategy in an anaerobic baffle reactor (ABR)...

The efficiency of deep aerated vertical flow constructed wetlands (DA-VFCWs) being operated in Hyderabad, India, was evaluated herein using physicochemical analysis and 16S rRNA amplicon sequencing. The results showed 2-4-fold higher removal rate coefficients for Biochemical oxygen demand (1.32---3.53 m/d) and nitrogen (0.88--1.36 m/d) in DA-VFCWs than those of passive VFCWs. Elevated sulfate concentration in the DA-VFCWs effluent (84-113 mg/L) indicated possibility of sulfur-driven autotrophic denitrification (SDAD) as a major pathway operating in these wetlands besides the classical nitrogen removal pathways...

To understand the role of denitrifying microbes during vegetation recovery in karst regions, we determined the basic physicochemical properties and abundance of denitrifying microbial functional genes ( nirS , nirK , fungal nirK , p 450 nor , and nosZ ) of 13 collected soil samples under three land use types (cropland, grassland, and plantation) in Northwest Guangxi, and investigated the changes in the abundance of denitrifying microbial functional genes and their driving factors. Results showed that soil pH, soil organic carbon, total nitrogen (TN), and exchangeable calcium (Caexe ) in plantation soil were significantly higher than those in cropland and grassland...

The utilization of anaerobic hydrolysate from agroforestry wastes is limited by dissolved lignin and aromatics, which have received insufficient attention despite their potential as excellent carbon sources for denitrification. This study aims to investigate the influence of hematite on lignin-derived aromatic compounds and denitrifying carbon sources, as well as to identify iron-reducing bacteria that utilize lignin-derived aromatic compounds as electron donors. The findings revealed that hematite facilitated the anaerobic fermentation of plant biomass, resulting in the production of small molecular organic acids...

The two-sludge anoxic dephosphation (DEPHANOX) process frequently encounters the challenge of elevated effluent ammonia levels in practical applications. In this study, the anaerobic ammonium oxidation (anammox) biofilm was introduced into the DEPHANOX system, transforming it into a three-sludge system, enabling synchronous nitrogen and phosphorus elimination, particularly targeting ammonia. Despite a chemical oxygen demand/total nitrogen ratio of 4.3±0.8 in the actual municipal wastewater and 4.5 h of aeration, the effluent total nitrogen was 13...

Constructed wetlands (CWs) are frequently used for effective biological treatment of nitrogen-rich wastewater with external carbon source addition; however, these approaches often neglect the interaction between plant litter and biochar in biochar-amended CW environments. To address this, we conducted a comprehensive study to assess the impacts of single or combined addition of common reed litter and reed biochar (pyrolyzed at 300 and 500 °C) on nitrogen removal, greenhouse gas emission, dissolved organic matter (DOM) dynamics, and microbial activity...

Denitrifying bacteria harboring the nitrate reductase S (nirS) gene convert active nitrogen into molecular nitrogen, and alleviate eutrophication in aquaculture water. Suspended particulate matter (SPM) is an important component of aquaculture water and a carrier for denitrification. SPM with different particle sizes were collected from a coastal high-altitude aquaculture pond in Maoming City, China. Diversity, community structure, abundance of nirS-type denitrifying bacteria on SPM and environmental influencing factors were studied using high-throughput sequencing, fluorescence quantitative PCR, and statistical analysis...

Tire wear particles (TWPs), as predominant microplastics (MPs) in road runoff, can be captured and retained by bioretention systems (BRS). This study aimed to investigate the effect of TWPs accumulation on nitrogen processes, focusing on soil characteristics, microbial community, and functional genes. Two groups of lab-scale bioretention columns containing TWPs (0 and 100 mg g-1 ) were established. The removal efficiencies of NH4 + -N and TN in BRS significantly decreased by 7.60%-24.79% and 1...

The synergistic partial-denitrification, anammox, and fermentation (SPDAF) process presents a promising solution to treat domestic and nitrate wastewaters. However, its capability to handle fluctuating C/N ratios (the ratios of COD to total inorganic nitrogen) in practical applications remains uncertain. In this study, the SPDAF process was operated for 236 days with C/N ratios of 0.7-3.5, and a high and stable efficiency of nitrogen removal (84.9 ± 7.8%) was achieved. The denitrification and anammox contributions were 6...

The over-utilizing of nitrogen fertilizers in paddy wetlands potentially threatens to the surrounding waterbody, and a deep understanding of the community and function of microorganisms is crucial for paddy non-point source pollution control. In this study, top soil samples (0-15 cm) of paddy wetlands under groundwater's irrigation at different depths (H1: 6.8 m, H2: 13.7 m, H3: 14.8 m, H4: 15.6 m, H5: 17.0 m, and H6: 17.8 m) were collected to investigate microbial community and function differences and their interrelation with soil properties...