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Environmental Science & Technology Aug 2023Bioelectrochemical systems (BESs) are considered to be energy-efficient to convert ammonium, which is present in wastewater. The application of BESs as a technology to...
Bioelectrochemical systems (BESs) are considered to be energy-efficient to convert ammonium, which is present in wastewater. The application of BESs as a technology to treat wastewater on an industrial scale is hindered by the slow removal rate and lack of understanding of the underlying ammonium conversion pathways. This study shows ammonium oxidation rates up to 228 ± 0.4 g-N m d under microoxic conditions (dissolved oxygen at 0.02-0.2 mg-O/L), which is a significant improvement compared to anoxic conditions (120 ± 21 g-N m d). We found that this enhancement was related to the formation of hydroxylamine (NHOH), which is rate limiting in ammonium oxidation by ammonia-oxidizing microorganisms. NHOH was intermediate in both the absence and presence of oxygen. The dominant end-product of ammonium oxidation was dinitrogen gas, with about 75% conversion efficiency in the presence of a microoxic level of dissolved oxygen and 100% conversion efficiency in the absence of oxygen. This work elucidates the dominant pathways under microoxic and anoxic conditions which is a step toward the application of BESs for ammonium removal in wastewater treatment.
Topics: Ammonium Compounds; Wastewater; Bioreactors; Oxidation-Reduction; Oxygen; Nitrogen
PubMed: 37498945
DOI: 10.1021/acs.est.3c02227 -
Current Opinion in Chemical Biology Apr 2017The most abundant transition metal in biological systems is iron. It is incorporated into protein cofactors and serves either catalytic, redox or regulatory purposes.... (Review)
Review
The most abundant transition metal in biological systems is iron. It is incorporated into protein cofactors and serves either catalytic, redox or regulatory purposes. Anaerobic ammonium oxidizing (anammox) bacteria rely heavily on iron-containing proteins - especially cytochromes - for their energy conservation, which occurs within a unique organelle, the anammoxosome. Both their anaerobic lifestyle and the presence of an additional cellular compartment challenge our understanding of iron processing. Here, we combine existing concepts of iron uptake, utilization and metabolism, and cellular fate with genomic and still limited biochemical and physiological data on anammox bacteria to propose pathways these bacteria may employ.
Topics: Ammonium Compounds; Bacteria, Anaerobic; Biological Transport; Coenzymes; Iron; Oxidation-Reduction
PubMed: 28364725
DOI: 10.1016/j.cbpa.2017.03.009 -
Bioresource Technology Jan 2022Microbial protein (MP) production by autotrophic hydrogen-oxidizing bacteria is regarded as a potentially sustainable approach to mitigate food crisis, water pollution,...
Microbial protein (MP) production by autotrophic hydrogen-oxidizing bacteria is regarded as a potentially sustainable approach to mitigate food crisis, water pollution, and climate change. Herein, a hybrid biological-inorganic (HBI) system which coupled energy-neutral ammonium recovery and in-situ upcycling for MP production was demonstrated. No energy and acids/bases were needed for ammonium recovery and pH control. The system was tested with different amounts of CO supply and operated at different operational modes (microbial fuel cell or microbial electrolysis cell mode). 0.381 g/L of biomass containing 64.79% of crude protein was produced using the recovered nitrogen and therefore led to 76.8% of ammonium recovery and 84.6% of COD removal from real municipal wastewater. The system although not yet optimal in terms of efficiency has a meaning in alleviating food crisis and environmental issues. Altogether, this study offers insight into developing an energy and resource-efficient power-to-protein process to supplement conventional food production globally.
Topics: Ammonium Compounds; Bacteria; Bacterial Proteins; Bioreactors; Hydrogen; Oxidation-Reduction; Wastewater
PubMed: 34748978
DOI: 10.1016/j.biortech.2021.126271 -
Journal of Exposure Science &... Sep 2022Quaternary ammonium compounds (QACs), commonly used in cleaning, disinfecting, and personal care products, have recently gained worldwide attention due to the massive...
BACKGROUND
Quaternary ammonium compounds (QACs), commonly used in cleaning, disinfecting, and personal care products, have recently gained worldwide attention due to the massive use of disinfectants during the COVID-19 pandemic. However, despite extensive use of these chemicals, no studies have focused on the analysis of QACs in human milk, a major route of exposure for infants.
OBJECTIVE
Our objectives were to identify and measure QACs in breast milk and evaluate early-life exposure to this group of compounds for nursing infants.
METHODS
Eighteen QACs, including 6 benzylalkyldimethyl ammonium compounds (BACs, with alkyl chain lengths of C8-C18), 6 dialkyldimethyl ammonium compounds (DDACs, C8-C18), and 6 alkyltrimethyl ammonium compounds (ATMACs, C8-C18), were measured in breast milk samples collected from U.S. mothers. Daily lactational intake was estimated based on the determined concentrations for 0-12 month old nursing infants.
RESULTS
Thirteen of the 18 QACs were detected in breast milk and 7 of them were found in more than half of the samples. The total QAC concentrations (ΣQAC) ranged from 0.33 to 7.4 ng/mL (median 1.5 ng/mL). The most abundant QAC was C14-BAC with a median concentration of 0.45 ng/mL. The highest median ΣQAC estimated daily intake (EDI) was determined for <1-month old infants based on the average (using the median concentration) and high (using the 95 percentile concentration) exposure scenarios (230 and 750 ng/kg body weight/day, respectively).
SIGNIFICANCE
Our findings provide the first evidence of the detection of several QACs in breast milk and identify breastfeeding as an exposure pathway to QACs for nursing infants.
IMPACT STATEMENT
Our findings provide the first evidence of QAC occurrence in breast milk and identify breastfeeding as one of the exposure pathways to QACs for nursing infants.
Topics: Ammonium Compounds; COVID-19; Disinfectants; Female; Humans; Infant; Infant, Newborn; Milk, Human; Pandemics; Quaternary Ammonium Compounds
PubMed: 35437305
DOI: 10.1038/s41370-022-00439-4 -
The ISME Journal Nov 2022The nitrogen cycle plays a major role in aquatic nitrogen transformations, including in the terrestrial subsurface. However, the variety of transformations remains...
The nitrogen cycle plays a major role in aquatic nitrogen transformations, including in the terrestrial subsurface. However, the variety of transformations remains understudied. To determine how nitrogen cycling microorganisms respond to different aquifer chemistries, we sampled groundwater with varying nutrient and oxygen contents. Genes and transcripts involved in major nitrogen-cycling pathways were quantified from 55 and 26 sites, respectively, and metagenomes and metatranscriptomes were analyzed from a subset of oxic and dysoxic sites (0.3-1.1 mg/L bulk dissolved oxygen). Nitrogen-cycling mechanisms (e.g. ammonia oxidation, denitrification, dissimilatory nitrate reduction to ammonium) were prevalent and highly redundant, regardless of site-specific physicochemistry or nitrate availability, and present in 40% of reconstructed genomes, suggesting that nitrogen cycling is a core function of aquifer communities. Transcriptional activity for nitrification, denitrification, nitrite-dependent anaerobic methane oxidation and anaerobic ammonia oxidation (anammox) occurred simultaneously in oxic and dysoxic groundwater, indicating the availability of oxic-anoxic interfaces. Concurrent activity by these microorganisms indicates potential synergisms through metabolite exchange across these interfaces (e.g. nitrite and oxygen). Fragmented denitrification pathway encoding and transcription was widespread among groundwater bacteria, although a considerable proportion of associated transcriptional activity was driven by complete denitrifiers, especially under dysoxic conditions. Despite large differences in transcription, the capacity for the final steps of denitrification was largely invariant to aquifer conditions, and most genes and transcripts encoding NO reductases were the atypical Sec-dependant type, suggesting energy-efficiency prioritization. Results provide insights into the capacity for cooperative relationships in groundwater communities, and the richness and complexity of metabolic mechanisms leading to the loss of fixed nitrogen.
Topics: Ammonia; Ammonium Compounds; Denitrification; Methane; Nitrates; Nitrites; Nitrogen; Nitrogen Cycle; Oxidation-Reduction; Oxidoreductases; Oxygen
PubMed: 35941171
DOI: 10.1038/s41396-022-01300-0 -
Applied Microbiology and Biotechnology May 2018In recent years, (bio)electrochemical systems (B)ES have emerged as an energy efficient alternative for the recovery of TAN (total ammonia nitrogen, including ammonia... (Review)
Review
In recent years, (bio)electrochemical systems (B)ES have emerged as an energy efficient alternative for the recovery of TAN (total ammonia nitrogen, including ammonia and ammonium) from wastewater. In these systems, TAN is removed or concentrated from the wastewater under the influence of an electrical current and transported to the cathode. Subsequently, it can be removed or recovered through stripping, chemisorption, or forward osmosis. A crucial parameter that determines the energy required to recover TAN is the load ratio: the ratio between TAN loading and applied current. For electrochemical TAN recovery, an energy input is required, while in bioelectrochemical recovery, electric energy can be recovered together with TAN. Bioelectrochemical recovery relies on the microbial oxidation of COD for the production of electrons, which drives TAN transport. Here, the state-of-the-art of (bio)electrochemical TAN recovery is described, the performance of (B)ES for TAN recovery is analyzed, the potential of different wastewaters for BES-based TAN recovery is evaluated, the microorganisms found on bioanodes that treat wastewater high in TAN are reported, and the toxic effect of the typical conditions in such systems (e.g., high pH, TAN, and salt concentrations) are described. For future application, toxicity effects for electrochemically active bacteria need better understanding, and the technologies need to be demonstrated on larger scale.
Topics: Ammonia; Ammonium Compounds; Bacteria; Electrochemistry; Electrodes; Oxidation-Reduction; Wastewater; Water Purification
PubMed: 29520602
DOI: 10.1007/s00253-018-8888-6 -
The Antimicrobial and Antibiofilm Potential of New Water-Soluble Tris-Quaternary Ammonium Compounds.International Journal of Molecular... Jun 2023The invention and innovation of highly effective antimicrobials are always crucial tasks for medical and organic chemistry, especially at the current time, when there is...
The invention and innovation of highly effective antimicrobials are always crucial tasks for medical and organic chemistry, especially at the current time, when there is a serious threat of shortages of effective antimicrobials following the pandemic. In the study presented in this article, we established a new approach to synthesizing three novel series of bioactive water-soluble tris-quaternary ammonium compounds using an optimized one-pot method, and we assessed their antimicrobial and antibiofilm potential. Five pathogenic microorganisms of the ESKAPE group, including highly resistant clinical isolates, were used as the test samples. Moreover, we highlighted the dependence of antibacterial activity from the hydrophilic-hydrophobic balance of the QACs and noted the significant performance of the desired products on biofilms with MBEC as low as 16 mg/L against bacteria and 8 mg/L against fungi. Particularly notable was the high activity against and , which are among the most resilient bacteria known. The presented work will provide useful insights for future research on the topic.
Topics: Quaternary Ammonium Compounds; Anti-Infective Agents; Anti-Bacterial Agents; Bacteria; Biofilms; Microbial Sensitivity Tests
PubMed: 37445691
DOI: 10.3390/ijms241310512 -
Molecules (Basel, Switzerland) Dec 2020In this review, the roles of room temperature ionic liquids (RTILs) and RTIL based solvent systems as proposed alternatives for conventional organic electrolyte... (Review)
Review
In this review, the roles of room temperature ionic liquids (RTILs) and RTIL based solvent systems as proposed alternatives for conventional organic electrolyte solutions are described. Ionic liquids are introduced as well as the relevant properties for their use in electrochemistry (reduction of ohmic losses), such as diffusive molecular motion and ionic conductivity. We have restricted ourselves to provide a survey on the latest, most representative developments and progress made in the use of ionic liquids as electrolytes, in particular achieved by the cyclic voltammetry technique. Thus, the present review comprises literature from 2015 onward covering the different aspects of RTILs, from the knowledge of these media to the use of their properties for electrochemical processes. Out of the scope of this review are heat transfer applications, medical or biological applications, and multiphasic reactions.
Topics: Ammonium Compounds; Chemical Phenomena; Electric Conductivity; Electrochemical Techniques; Electrochemistry; Electrolytes; Imidazoles; Ionic Liquids; Molecular Structure; Organophosphorus Compounds; Pyrrolidines; Solvents; Sulfonium Compounds; Temperature; Viscosity
PubMed: 33317199
DOI: 10.3390/molecules25245812 -
Trends in Microbiology Jun 2024Nitrate ammonifiers are a taxonomically diverse group of microorganisms that reduce nitrate to ammonium, which is released, and thereby contribute to the retention of... (Review)
Review
Nitrate ammonifiers are a taxonomically diverse group of microorganisms that reduce nitrate to ammonium, which is released, and thereby contribute to the retention of nitrogen in ecosystems. Despite their importance for understanding the fate of nitrate, they remain a largely overlooked group in the nitrogen cycle. Here, we present the latest advances on free-living microorganisms using NrfA to reduce nitrite during ammonification. We describe their diversity and ecology in terrestrial and aquatic environments, as well as the environmental factors influencing the competition for nitrate with denitrifiers that reduce nitrate to gaseous nitrogen species, including the greenhouse gas nitrous oxide (NO). We further review the capacity of ammonifiers for other redox reactions, showing that they likely play multiple roles in the cycling of elements.
Topics: Bacteria; Nitrates; Nitrous Oxide; Ecosystem; Nitrites; Biodiversity; Oxidation-Reduction; Ammonium Compounds; Nitrogen Cycle; Nitrogen
PubMed: 38462391
DOI: 10.1016/j.tim.2024.02.007 -
ELife Aug 2020In order to enter a cell, an ammonium ion must first dissociate to form an ammonia molecule and a hydrogen ion (a proton), which then pass through the cell membrane...
In order to enter a cell, an ammonium ion must first dissociate to form an ammonia molecule and a hydrogen ion (a proton), which then pass through the cell membrane separately and recombine inside.
Topics: Ammonia; Ammonium Compounds; Ion Transport; Nitrosomonas; Oxidation-Reduction
PubMed: 32840481
DOI: 10.7554/eLife.61148