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Environmental Pollution (Barking, Essex... May 2024In this study, the activity, aggregation performance, microbial community and functional proteins of aerobic granular sludge (AGS) in response to acute inhibition by...
In this study, the activity, aggregation performance, microbial community and functional proteins of aerobic granular sludge (AGS) in response to acute inhibition by different concentrations of polystyrene microplastics (PS-MPs) were investigated. As the PS-MPs concentration increased from 0 mg/L to 200 mg/L, the specific nitrogen removal rate and the activity of enzymes were inhibited. The inhibition of specific nitrite reduction rate (SNIRR) and specific nitrate reduction rate (SNRR) was most obvious at the PS-MPs concentration of 100 mg/L, and that of nitrite reductase (NIR) and nitrate reductase (NR) was most obvious at the concentration of 50 mg/L. But the inhibitory effects were mitigated at the concentration of 200 mg/L. The increase of reactive oxygen species (ROS) and lactate dehydrogenase (LDH) indicated that the cells were damaged with the increase of PS-MPs concentration. The content of proteins and polysaccharides in extracellular polymeric substances (EPS) decreased, especially the polysaccharides were more affected. Analysis of zeta potential, hydrophobicity and surface thermodynamics of AGS revealed that addition of PS-MPs was unfavorable for AGS aggregation. It was also found that bacteria genera associated with EPS secretion and nitrogen removal functions were inhibited, while functions associated with cell metabolism, protein synthesis and cell repair were enhanced. This also confirmed that acute inhibition of PS-MPs had a detrimental effect on the nitrogen removal and aggregation performance of AGS. This study can provide theoretical support for the operation of AGS reactors under microplastics impact load.
Topics: Polystyrenes; Sewage; Microplastics; Nitrogen; Waste Disposal, Fluid; Water Pollutants, Chemical; Bacteria; Aerobiosis; Reactive Oxygen Species; Nitrate Reductase
PubMed: 38580060
DOI: 10.1016/j.envpol.2024.123923 -
Journal of Hazardous Materials May 2024Sb(III) and As(III) share similar chemical features and coexist in the environment. However, their oxidase enzymes have completely different sequences and structures....
Sb(III) and As(III) share similar chemical features and coexist in the environment. However, their oxidase enzymes have completely different sequences and structures. This raises an intriguing question: Could Sb(III)-oxidizing prokaryotes (SOPs) also oxidize As(III), and vice versa? Regarding this issue, previous investigations have yielded unclear, incorrect and even conflicting data. This work aims to address this matter. First, we prepared an enriched population of SOPs that comprises 55 different AnoA genes, lacking AioAB and ArxAB genes. We found that these SOPs can oxidize both Sb(III) and As(III) with comparable capabilities. To further confirm this finding, we isolated three cultivable SOP strains that have AnoA gene, but lack AioAB and ArxAB genes. We observed that they also oxidize both Sb(III) and As(III) under both anaerobic and aerobic conditions. Secondly, we obtained an enriched population of As(III)-oxidizing prokaryotes (AOPs) from As-contaminated soils, which comprises 69 different AioA genes, lacking AnoA gene. We observed that the AOP population has significant As(III)-oxidizing activities, but lack detectable Sb(III)-oxidizing activities under both aerobic and anaerobic conditions. Therefore, we convincingly show that SOPs can oxidize As(III), but AOPs cannot oxidize Sb(III). These findings clarify the previous ambiguities, confusion, errors or contradictions regarding how SOPs and AOPs oxidize each other's substrate.
Topics: Anaerobiosis; Oxidation-Reduction; Aerobiosis; Antimony; Prokaryotic Cells; Soil Microbiology; Bacteria; Soil Pollutants
PubMed: 38574656
DOI: 10.1016/j.jhazmat.2024.134135 -
The New Phytologist Jun 2024Shoot-level emissions of aerobically produced methane (CH) may be an overlooked source of tree-derived CH, but insufficient understanding of the interactions between...
Shoot-level emissions of aerobically produced methane (CH) may be an overlooked source of tree-derived CH, but insufficient understanding of the interactions between their environmental and physiological drivers still prevents the reliable upscaling of canopy CH fluxes. We utilised a novel automated chamber system to continuously measure CH fluxes from the shoots of Pinus sylvestris (Scots pine) saplings under drought to investigate how canopy CH fluxes respond to the drought-induced alterations in their physiological processes and to isolate the shoot-level production of CH from soil-derived transport and photosynthesis. We found that aerobic CH emissions are not affected by the drought-induced stress, changes in physiological processes, or decrease in photosynthesis. Instead, these emissions vary on short temporal scales with environmental drivers such as temperature, suggesting that they result from abiotic degradation of plant compounds. Our study shows that aerobic CH emissions from foliage are distinct from photosynthesis-related processes. Thus, instead of photosynthesis rates, it is more reliable to construct regional and global estimates for the aerobic CH emission based on regional differences in foliage biomass and climate, also accounting for short-term variations of weather variables such as air temperature and solar radiation.
Topics: Photosynthesis; Pinus sylvestris; Methane; Droughts; Plant Shoots; Aerobiosis; Temperature; Plant Leaves; Biomass
PubMed: 38549455
DOI: 10.1111/nph.19724 -
Journal of Environmental Management Apr 2024The disintegration and instability of aerobic granular sludge (AGS) systems during long-term operation pose significant challenges to its practical implementation, and...
The disintegration and instability of aerobic granular sludge (AGS) systems during long-term operation pose significant challenges to its practical implementation, and rapid recovery strategies for disintegrated AGS are gaining more attention. In this study, the recovery and re-stabilization of disintegrated AGS was investigated by adding chitosan to a sequencing batch reactor and simultaneously adjusting the pH to slightly acidic condition. Within 7 days, chitosan addition under slight acidity led to the re-aggregation of disintegrated granules, increasing the average particle size from 166.4 μm to 485.9 μm. Notably, sludge volume indexes at 5 min (SVI) and 30 min (SVI) decreased remarkably from 404.6 mL/g and 215.1 mL/g (SVI/SVI = 0.53) to 49.1 mL/g and 47.6 mL/g (SVI/SVI = 0.97), respectively. Subsequent operation for 43 days successfully re-stabilized previous collapsed AGS system, resulting in an average particle size of 750.2 μm. These mature and re-stabilized granules exhibited characteristics of large particle size, excellent settleability, compact structure, and high biomass retention. Furthermore, chitosan facilitated the recovery of COD and nitrogen removal performances within 17-23 days of operation. It effectively facilitated the rapid aggregation of disintegrated granules by charge neutralization and bridging effects under a slightly acidic environment. Moreover, the precipitated chitosan acted as carriers, promoting the adhesion of microorganisms once pH control was discontinued. The results of batch tests and microbial community analysis confirmed that chitosan addition increased sludge retention time, enriching slow-growing microorganisms and enhancing the stability and pollutant removal efficiency of the AGS system.
Topics: Sewage; Waste Disposal, Fluid; Chitosan; Bioreactors; Aerobiosis; Nitrogen
PubMed: 38547824
DOI: 10.1016/j.jenvman.2024.120613 -
Environmental Science and Pollution... Apr 2024The Anaerobic Baffled Reactor (ABR) is an effective solution for landfill leachate treatment using an anaerobic fermentation process, which helps to reduce operating...
The Anaerobic Baffled Reactor (ABR) is an effective solution for landfill leachate treatment using an anaerobic fermentation process, which helps to reduce operating costs and sludge volume. To better understand the biological, chemical, and physical processes involved, especially when combining the ABR with an aerobic component, the study aimed to investigate the performance of an Anaerobic-Aerobic Hybrid Baffled Reactor (AABR) that includes an Anaerobic Filter (AF) for treating landfill leachate. This research utilized two glass reactors. The first reactor, designated as AABR-AF, consisted of six independent rectangular glass chambers arranged side by side. The third and sixth chamber designed for aerobic treatment and AF, respectively. The second reactor was used as a control reactor and did not include any aerobic chamber. The highest Removal Efficiencies (REs) for turbidity, COD, BOD, TP, TKN, nitrate, TOC, and TSS in the AABR-AF and ABR-AF were found to be (65.4% and 56.3%), (98.3% and 94.1%), (98.1% and 93.2%), (86.4% and 65%), (89.2% and 76.7%), (81.2% and 64.4%), (88.2% and 79.4%), and (72.4% and 68.5%), respectively. These optimal REs were achieved at an HRT of 48 h and an OLR of 10 kg/m.d. Also, the highest and the lowest REs in Heavy Metals (HMs) were 89.57% for manganese in AABR-AF and 6.59% for nickel in ABR-AF, in an OLR of 10 kg/m.d, respectively. The effective removal of Organic Matters (OMs) from landfill leachate using the AABR-AF and ABR-AF was found to be strongly influenced by HRT and OLR. The AABR-AF configuration, featuring a single aerobic chamber in the reactor, exhibited a higher efficiency in removing OMs compared to the ABR-AF configuration.
Topics: Anaerobiosis; Bioreactors; Water Pollutants, Chemical; Waste Disposal, Fluid; Aerobiosis
PubMed: 38530522
DOI: 10.1007/s11356-024-32954-2 -
Journal of Environmental Management Apr 2024Research has evolved on aerobic granular sludge (AGS) process, but still there are very few studies on the treatment of excess AGS sludge, with almost none considering...
Research has evolved on aerobic granular sludge (AGS) process, but still there are very few studies on the treatment of excess AGS sludge, with almost none considering its aerobic digestion. Here therefore, the aerobic digestibility of typical AGS sludge was assessed. Granules were produced from acetate-based synthetic wastewater (WW) and were subjected to aerobic digestion for 64 d. The stabilization process was monitored over time through physical-chemical parameters, oxygen uptake rates (OUR) and 16S rRNA gene sequencing. The microbial analyses revealed that the cultivated granules were dominated by slow-growing bacteria, mainly ordinary heterotrophic organisms with potential for polyhydroxyalkanoates (PHA) aerobic storage (PHA-OHOs), polyphosphate and glycogen accumulating organisms (PAOs and GAOs), fermentative anaerobes and nitrifiers (AOB and NOB). Differential abundance analysis of the bacterial data (before versus after digestion) discriminated between the most vulnerable microbiome genera and those most resistant to aerobic digestion. Furthermore, modeling of the stabilization process determined that the endogenous decay rate constant (b) for the heterotrophs present in the granules was notably low; b = 0.05 d (average), four times less than for common activated sludge (AS), which is rated at 0.2 d. For first time, the research reveals another important feature of AGS sludge, i.e. the slow-decaying character of its bacteria (along with their known slow-growing character). This results in slower stabilization, need of bigger digesters and reconsideration of the specific OUR limits in biosolids regulations (SOUR limit of 1.5 mg/gTSS.h), for waste AGS compared to conventional waste AS. The study suggests that aerobic digestion of waste AGS (fully-granulated) could differ from that of conventional AS. Future work is needed on aerobic digestibility of real AGS sludges from municipal and industrial WWs, compared to synthetic WWs.
Topics: Sewage; RNA, Ribosomal, 16S; Waste Disposal, Fluid; Genes, rRNA; Bioreactors; Bacteria; Aerobiosis; Nitrogen
PubMed: 38520857
DOI: 10.1016/j.jenvman.2024.120639 -
Journal of Environmental Management Apr 2024It is challenging to differentiate bacteria residing in the same habitat by direct observation. This difficulty impedes the harvest, application and manipulation of...
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 intact bacteria and their living surroundings can be analyzed as an integrated target, which eliminates the need for the complex pre-processing of samples. Under the optimal synchronous scanning parameter (Δλ = 40 nm), each bacterium possesses a unique fluorescence spectral structure and the derivative synchronous fluorescence technique can significantly improve the spectral resolution compared to other conventional fluorescence methods, which enables the rapid differentiation of different bacteria through derivative synchronous fluorescence spectra as fast as 2 min per spectrum. Additionally, the derivative synchronous fluorescence technique can extract the spectral signals contributed by bacterial extracellular substances produced in the biological nitrogen removal process. Moreover, the results obtained from our method can reflect the real-time denitrification properties of bacteria in the biological nitrogen removal process of wastewater. All these merits highlight derivative synchronous fluorescence spectroscopy as a promising analytic method in the environmental field.
Topics: Denitrification; Fluorescence; Aerobiosis; Nitrification; Bacteria; Nitrogen; Heterotrophic Processes; Nitrites
PubMed: 38520848
DOI: 10.1016/j.jenvman.2024.120587 -
Cellular & Molecular Immunology May 2024
Topics: Cell Differentiation; CD4-Positive T-Lymphocytes; Glycolysis; Neoplasms; Humans; Animals; Aerobiosis; Mice
PubMed: 38514872
DOI: 10.1038/s41423-024-01154-w -
Microscopy Research and Technique Aug 2024Nanotechnology and its byproducts are used increasingly considering its global nanotechnology market size and many applications in the health field. The aim of the...
The effects of biological and chemical silver nanoparticles along with aerobic and anaerobic training protocols on tissues: Morphological and histopathological evaluation.
Nanotechnology and its byproducts are used increasingly considering its global nanotechnology market size and many applications in the health field. The aim of the present study was to investigate the effect of aerobic and anaerobic exercises on cellular uptake of nanoparticles in body tissues. Fusarium oxysporum was used to synthesize biological AgNPs in silver nitrate solution and UV-vis spectrophotometer; XRD and TEM were used to confirm production of nanoparticles. Moreover, 45 male Wistar rats were purchased and randomly divided into 9 equal groups including healthy control groups, aerobic preparation, anaerobic preparation, biological AgNPs, chemical AgNPs, biological AgNPs+aerobic preparation, biological AgNPs+anaerobic preparation, chemical AgNPs+ aerobic preparation, chemical AgNPs+anaerobic preparation. In order to induce aerobic and anaerobic preparation and to create tissue adaptations, male rats completed two types of aerobic and anaerobic protocols three sessions per week for 10 weeks. At the end of the study, sampling was done for histopathology study. The size and shape of AgNPs was 20-30 nm and spherical to polygonal, respectively. The results showed that anaerobic exercise was significantly effective in weight loss. The chemical nanoparticle group led to more intensive tissue degradation in all variables and there were no significant tissue changes in the aerobic, anaerobic, the biological nanoparticles + aerobic and anaerobic groups. It seems that biological AgNPs are more effective than chemical AgNPs on body tissues and chemical AgNPs lead to more tissue damage in most variables. RESEARCH HIGHLIGHTS: There were severe degradative histological effects in the chemical AgNPs groups compare biological AgNPs groups, in terms of most variables.
Topics: Animals; Silver; Rats, Wistar; Metal Nanoparticles; Male; Rats; Anaerobiosis; Physical Conditioning, Animal; Aerobiosis; Fusarium
PubMed: 38511835
DOI: 10.1002/jemt.24553 -
Chemosphere Apr 2024In this study, an aerobic granular sludge electrochemical system (AGES) was established by applying the micro-electric field to an aerobic granular sludge (AGS) reactor...
In this study, an aerobic granular sludge electrochemical system (AGES) was established by applying the micro-electric field to an aerobic granular sludge (AGS) reactor for the degradation of sulfamethoxazole (SMZ). Under the stimulation of the micro-electric field, the granulation of sludge was improved and the degradation rate of SMZ was enhanced. The features of granular sludge were characterized by scanning electron microscopy and X-ray diffraction. The optimal degradation rate of SMZ (88%) was obtained at the voltage of 3 V and the effective electrode area of 800 mm. The results of kinetics analyses revealed that the degradation of SMZ by AGES can be fitted with the second-order kinetic equation, showing a degradation rate constant (k) of 0.001 L mol·min. The degradation products of SMZ in the AGES system were detected by LC-MS and their possible degradation routes were elucidated. The micro-electric field in the AGES system played a selective role in microbes' enrichment and growth, changing the diversity of the microbial community. Pseudomonas, Tolumonas, and Acidovorax were the dominant bacteria in the AGES system, which is accountable for the abatement of SMZ and nutrients. This work provides a green means for improving AGS and paves the way for applying the AGS process to real-world wastewater treatment.
Topics: Sewage; Waste Disposal, Fluid; Aerobiosis; Bioreactors; Microbiota; Nitrogen
PubMed: 38499071
DOI: 10.1016/j.chemosphere.2024.141741