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1.
J Appl Microbiol ; 135(6)2024 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-38849313

RESUMEN

AIMS: Understanding the inhibitory effects of natural organic substances on soil-borne pathogenic fungi and the relevant molecular mechanisms are highly important for future development of green prevention and control technology against soil-borne diseases. Our study elucidates the inhibitory effect of the combined application of humic acids (HAs) and chitosan on Alternariasolani and the light on the corresponding mechanism. METHODS AND RESULTS: The effect on A. solani growth by HAs incorporated with chitosan was investigated by plate culture and the corresponding mechanism was revealed using transcriptomics. The colony growth of A. solani was suppressed with the highest inhibition rate 33.33% when swine manure HAs was compounded with chitosan at a ratio of 1:4. Chitosan changed the colony morphology from round to irregularly. RNA-seq in the HAs and chitosan (HC) treatment revealed 239 differentially expressed genes compared with the control. The unigenes associated with enzymes activities related to growth and biological processes closely related to mycelial growth and metabolism were downregulated. RNA-seq also revealed that chitosan altered the expression of genes related to secondary metabolism, fungal cell wall formation and polysaccharide synthesis, and metabolism. Meanwhile, weighted gene co-expression network analysis showed that, genes expression in the module positively correlated with mycelial growth was significantly reduced in the HC treatment; and the results were verified by real-time quantitative polymerase chain reaction. CONCLUSIONS: The co-inhibition effect of HAs and chitosan on A. solani is associated with downregulated genes expression correlated with mycelial growth.


Asunto(s)
Alternaria , Quitosano , Perfilación de la Expresión Génica , Sustancias Húmicas , Quitosano/farmacología , Alternaria/efectos de los fármacos , Alternaria/genética , Alternaria/crecimiento & desarrollo , Animales , Transcriptoma , Porcinos , Estiércol/microbiología , Microbiología del Suelo , Micelio/crecimiento & desarrollo , Micelio/efectos de los fármacos , Micelio/genética
2.
Environ Res ; 259: 119537, 2024 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-38960362

RESUMEN

To recover methane from waste activated sludge through anaerobic digestion (AD) is one promising alternative to achieve carbon neutrality for wastewater treatment plants. However, humic acids (HAs) are one of the major compositions in waste activated sludge, and their accumulation performs inhibition effects on AD. This study investigated the potentials of biochar (BC) in alleviating inhibition effects of HAs on AD. Results showed that although the accumulated HAs reduced methane yield by 9.37% compared to control, the highest methane yield, 132.6 mL CH4/g VSS, was obtained after adding BC, which was 45.9% higher than that in HA group. Mechanism analysis showed that BC promoted the activities of hydrolase such as protease and α-glucosidase, which were 69.7% and 29.7% higher than those in HA group, respectively. The conversion of short-chain fatty acids was accelerated. In addition, the evolutions of electroactive microorganisms like Clostridium_sensu_stricto_13 and Methanosaeta were consistent with the activitiies of electron transfer and the contents of cytochrome c. Furthermore, parts of HAs rather than all of them were adsorbed by BC, and the remaining free HAs and BC formed synergistic effects on methanogenesis, then both CO2 reduction and acetoclastic methanogenesis pathways were improved. The findings may provide some solutions to alleviate inhibition effects of HAs on AD.


Asunto(s)
Carbón Orgánico , Sustancias Húmicas , Metano , Carbón Orgánico/química , Carbón Orgánico/farmacología , Anaerobiosis , Metano/metabolismo , Aguas del Alcantarillado/microbiología , Eliminación de Residuos Líquidos/métodos , Reactores Biológicos
3.
Ecotoxicol Environ Saf ; 269: 115854, 2024 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-38154210

RESUMEN

Chlorination is a versatile technique to combat water-borne pathogens. Over the last years, there has been continued research interest to abate the formation of chlorinated disinfection by-products (DBPs). To prevent hazardous DBPs in drinking water, it is decided to diminish organic precursors, among which humic acids (HA) resulting from the decomposition and transformation of biomass. Metal-organic frameworks (MOFs) such as zeolitic imidazolate frameworks (ZIFs) have recently received tremendous attention in water purification. Herein, customized ZIF-67 MOFs possessing various physicochemical properties were prepared by changing the cobalt source. The HA removal by ZIF-67-Cl, ZIF-67-OAc, ZIF-67-NO3, and ZIF-67-SO4 were 85.6%, 68.9%, 86.1%, and 87.4%, respectively, evidently affected by the specific surface area. HA uptake by ZIF-67-SO4 indicated a removal efficiency beyond 90% in 4  90% after 60 min mixing the solution with 0.3 g L-1 ZIF-67-SO4. Notably, an acceptable removal performance (∼72.3%) was obtained even at HA concentrations up to 100 mg L-1. The equilibrium data fitted well with the isotherm models in the order of Langmuir> Hill > BET> Khan > Redlich-Peterson> Jovanovic> Freundlich > and Temkin. The maximum adsorption capacity qm for HA uptake by ZIF-67-SO4 was 175.89 mg g-1, well above the majority of adsorbents. The pseudo-first-order model described the rate of HA adsorption by time. In conclusion, ZIF-67-SO4 presented promising adsorptive properties against HA. Further studies would be needed to minimize cobalt leaching from the ZIF-67-SO4 structure and improve its reusability safely, to ensure its effectiveness and the economy of adsorption system.


Asunto(s)
Estructuras Metalorgánicas , Contaminantes Químicos del Agua , Sustancias Húmicas , Cobalto , Adsorción , Contaminantes Químicos del Agua/análisis
4.
J Environ Manage ; 370: 122555, 2024 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-39299130

RESUMEN

Humic acids (HAs) would be excessively released during thermal hydrolysis pretreatment (THP) and deeply disturb anaerobic digestion (AD) of waste activated sludge (WAS). The molecular weights of HAs could affect HAs entering microbial cells, binding with digestive enzymes and participating in electron transfer, thereby determining its influences on sludge AD. Results in this study confirmed the different influences of HAs from diverse sources on sludge AD indeed had significant correlations with their molecular weights. The presence of commercial HAs (SAHA) inhibited methane production by 53.3% at 0.5 g/L while HAs extracted from raw sludge (WNHA) increased methane production by 20.5% at the same concentration, which attribute to the comprehensive impacts from their differences in functional group compositions and molecular weights. Moreover, comparing to WNHA, the HAs extracted from thermally hydrolyzed sludge (THHA) showed unchanged functional group compositions but reduced methane generation facilitation to 5.1%, which only be due to its decreased molecular weights. In-depth research indicated that HAs influences on enzymes were closely relative to its molecular weight. HAs with greater molecular weights presented more significant inhibition to extracellular enzymes while micromolecular HAs affected intracellular enzymes more. Furthermore, macromolecular HAs promoted sludge solubilization and acidification but hindered hydrolysis and methanogenesis, whereas micromolecular HAs promoted acidification but inhibited methanogenesis. This study underscored the importance of changes in molecular weight of HAs during sludge THP, offering insights into previous discrepancies in reports on HAs effects on sludge AD.

5.
J Environ Manage ; 370: 122366, 2024 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-39243649

RESUMEN

In recent years, increasing attention has been paid to the possibility of converting waste materials, e.g. manure, bio-waste, green waste, waste from the water and sewage industries (e.g. post-fermentation sludge), and agri-food waste into biochars (BCs) by pyrolysis. The ability of biochar to improve soil health and fertility is driving growing interest in its use as a soil amendment. A high soil stability of BCs and their excellent nutrient sorption properties are the main reasons for the superiority of such materials over other organic soil amendments. In addition, BCs can retain soil-relevant compounds, including humic substances (HSs). Since most of the resources used to produce humic fertilisers are non-renewable, the effluent from anaerobic digestion of sewage sludge (reject water, RW), which contains high levels of HSs, is considered a promising target for their recovery. In this study, the potential of ten BCs derived from pine, oak, straw, sunflower, and digestate at different pyrolysis temperatures for the recovery of HSs from RW was evaluated. The sorption of HSs on the applied BCs was conducted using contact method for 24 h and then determined spectrophotometrically. The most effective sorbents for HSs from RW were BCs obtained from straw in the low and high temperatures with the sorption capacity of 3.10 mg g-1 and 5.31 mg g-1, respectively. It was observed that the BCs produced from the same biomass at different pyrolysis temperatures had different sorption capacities for FA, HA, and a mixture of these compounds. The results indicated that BCs obtained from sunflower at different temperatures and oak at high temperature were the most promising sorbents for the recovery of HSs from RW. Such materials have the potential to be applied to soil and were selected for further evaluation due to their ability to enhance soil quality and immobilize pollutants. Further studies will assess their effectiveness in different soil conditions, their stability and persistence, and their impact on plant health and growth.

6.
J Environ Manage ; 357: 120767, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38560953

RESUMEN

The enhancing effects of anodes on the degradation of the organochlorine pesticide atrazine (ATR) in soil within microbial electrochemical systems (MES) have been extensively researched. However, the impact and underlying mechanisms of soil microbial electrochemical systems (MES) on ATR degradation, particularly under conditions involving the addition of humic acids (HAs), remain elusive. In this investigation, a soil MES supplemented with humic acids (HAs) was established to assess the promotional effects and mechanisms of HAs on ATR degradation, utilizing EEM-PARAFAC and SEM analyses. Results revealed that the maximum power density of the MES in soil increased by 150%, and the degradation efficiency of ATR improved by over 50% following the addition of HAs. Furthermore, HAs were found to facilitate efficient ATR degradation in the far-anode region by mediating extracellular electron transfer. The components identified as critical in promoting ATR degradation were Like-Protein and Like-Humic acid substances. Analysis of the microbial community structure indicated that the addition of HAs favored the evolution of the soil MES microbial community and the enrichment of electroactive microorganisms. In the ATR degradation process, the swift accumulation of Hydrocarbyl ATR (HYA) was identified as the primary cause for the rapid degradation of ATR in electron-rich conditions. Essentially, HA facilitates the reduction of ATR to HYA through mediated bonded electron transfer, thereby markedly enhancing the efficiency of ATR degradation.


Asunto(s)
Atrazina , Herbicidas , Contaminantes del Suelo , Sustancias Húmicas/análisis , Suelo/química , Microbiología del Suelo , Herbicidas/química , Contaminantes del Suelo/química
7.
World J Microbiol Biotechnol ; 40(6): 182, 2024 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-38668902

RESUMEN

The effect of barium ions on the biomineralization of calcium and magnesium ions is often overlooked when utilizing microbial-induced carbonate precipitation technology for removing barium, calcium, and magnesium ions from oilfield wastewater. In this study, Bacillus licheniformis was used to bio-precipitate calcium, magnesium, and barium ions. The effects of barium ions on the physiological and biochemical characteristics of bacteria, as well as the components of extracellular polymers and mineral characteristics, were also studied in systems containing coexisting barium, calcium, and magnesium ions. The results show that the increasing concentrations of barium ions decreased pH, carbonic anhydrase activity, and concentrations of bicarbonate and carbonate ions, while it increased the contents of humic acids, proteins, polysaccharides, and DNA in extracellular polymers in the systems containing all three types of ions. With increasing concentrations of barium ions, the content of magnesium within magnesium-rich calcite and the size of minerals precipitated decreased, while the full width at half maximum of magnesium-rich calcite, the content of O-C=O and N-C=O, and the diversity of protein secondary structures in the minerals increased in systems containing all three coexisting ions. Barium ions does inhibit the precipitation of calcium and magnesium ions, but the immobilized bacteria can mitigate the inhibitory effect. The precipitation ratios of calcium, magnesium, and barium ions reached 81-94%, 68-82%, and 90-97%. This research provides insights into the formation of barium-enriched carbonate minerals and offers improvements for treating oilfield wastewater.


Asunto(s)
Bacillus licheniformis , Bario , Biomineralización , Calcio , Magnesio , Magnesio/metabolismo , Bacillus licheniformis/metabolismo , Bario/metabolismo , Calcio/metabolismo , Aguas Residuales/microbiología , Aguas Residuales/química , Concentración de Iones de Hidrógeno , Iones , Anhidrasas Carbónicas/metabolismo , Carbonato de Calcio/metabolismo
8.
Microb Ecol ; 85(1): 137-145, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-35066616

RESUMEN

The use of metal-based and, particularly, Al2O3 nanoparticles (Al2O3-NP) for diverse purposes is exponentially growing. However, the growth of such promissory market is not accompanied by a parallel extensive investigation related to the impact of this pollution on groundwater and biological systems. Pseudomonas species, ubiquitous, environmentally critical microbes, frequently respond to stress conditions with diverse strategies that generally include extracellular polymeric substances (EPS) formation. The aim of this study is to report that changes in the aqueous environment, particularly, the addition of Al2O3-NP without and with humic acids, induce different adaptive strategies of Pseudomonas aeruginosa early biofilms. To this purpose, early biofilms were incubated in diluted culture media without (control) and with Al2O3-NP, and with humic acids (HA-control, HA-Al2O3-NP) for 24 h. 3D colonies with EPS strings and isolated bacteria in their surroundings were detected in the control biofilms. Unlikely, an unusual adaptive behaviour was developed in the presence of Al2O3-NP. Bacteria opt to disassemble the 3D arrangements and to implement a 2D network promoting morphological and size changes of bacterial cells (small coccoid shapes). Remarkably, this strategy allows their temporarily non-EPS-depending survival without decreasing the number of cells. This behaviour was not observed with ZnO-NP, HA-Al2O3-NP, or HA-ZnO-NP. Physicochemical analysis revealed that HA were adsorbed on Al2O3-NP and promoted the Al(III) ions complexation. This supports the hypothesis that the reduction of toxicity of Al ions and the 3D colony formation in the presence of HA-Al2O3-NP is promoted by the complexation of the metal ions with HA components.


Asunto(s)
Microbiota , Nanopartículas , Óxido de Zinc , Sustancias Húmicas/análisis , Óxido de Zinc/química , Iones
9.
Int J Mol Sci ; 24(2)2023 Jan 06.
Artículo en Inglés | MEDLINE | ID: mdl-36674650

RESUMEN

The current study evaluates the role of reactive oxygen species (ROS) in bioeffects of magnetite nanoparticles (MNPs), such as bare (Fe3O4), humic acids (Fe3O4-HA), and 3-aminopropyltriethoxysilane (Fe3O4-APTES) modified MNPs. Mössbauer spectroscopy was used to identify the local surrounding for Fe atom/ions and the depth of modification for MNPs. It was found that the Fe3O4-HA MNPs contain the smallest, whereas the Fe3O4-APTES MNPs contain the largest amount of Fe2+ ions. Bioluminescent cellular and enzymatic assays were applied to monitor the toxicity and anti-(pro-)oxidant activity of MNPs. The contents of ROS were determined by a chemiluminescence luminol assay evaluating the correlations with toxicity/anti-(pro-)oxidant coefficients. Toxic effects of modified MNPs were found at higher concentrations (>10−2 g/L); they were related to ROS storage in bacterial suspensions. MNPs stimulated ROS production by the bacteria in a wide concentration range (10−15−1 g/L). Under the conditions of model oxidative stress and higher concentrations of MNPs (>10−4 g/L), the bacterial bioassay revealed prooxidant activity of all three MNP types, with corresponding decay of ROS content. Bioluminescence enzymatic assay did not show any sensitivity to MNPs, with negligible change in ROS content. The results clearly indicate that cell-membrane processes are responsible for the bioeffects and bacterial ROS generation, confirming the ferroptosis phenomenon based on iron-initiated cell-membrane lipid peroxidation.


Asunto(s)
Nanopartículas de Magnetita , Especies Reactivas de Oxígeno , Nanopartículas de Magnetita/toxicidad , Nanopartículas de Magnetita/química , Bacterias , Oxidantes
10.
Molecules ; 28(20)2023 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-37894563

RESUMEN

This work explores the effect of humic acids (HA) fractionation on the sorption ability of a natural zeolite (NYT)-HA adduct. HA were extracted from compost, fractionated via the pH fractionation method, and characterized via UV-Vis spectroscopy and gel permeation chromatography. The HA samples were immobilized onto NYT via thermal treatment. The resulting adducts (NYT-HA) were tested for their ability to remove methylene blue (MB) from an aqueous solution. It was found that the sorption performance of NYT-HA strongly depends on the chemical characteristics of humic acids. Sorption capacity increased with the molecular weight and hydrophobicity degree of the HA fractions. Hydrophobic and π-π interactions are likely the primary mechanisms by which MB interacts with HA. The sorption kinetic data conform to the pseudo-second-order model. The Freundlich isotherm model adequately described the sorption equilibrium and revealed that the uptake of MB onto NYT-HA is endothermic in nature.

11.
Bull Exp Biol Med ; 175(2): 210-214, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37464194

RESUMEN

The effect of humic acids and substances with similar action - derivatives of succinic acid (ethylmethylhydroxypyridine succinate) and combined agent consisting of succinic acid, nicotinamide, riboflavin, and riboxin on the performance and stress resistance of experimental rats was studied. Performance was assessed in the test of exhaustive forced swimming with a load, stress resistance was evaluated by the serum level of corticosterone and open field behavior, and the state of anaerobic metabolism was estimated by the serum level of lactate after swimming test. Humic acids from peat showed anti-stress activity comparable to that of the officinal preparation and preventive effect on fatigue during physical exercise. They can be recommended as a component for the development of drugs that increase human performance and stress resistance.


Asunto(s)
Sustancias Húmicas , Suelo , Ratas , Humanos , Animales , Sustancias Húmicas/análisis , Ácido Succínico , Fatiga , Natación
12.
Bull Exp Biol Med ; 175(3): 353-357, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37563533

RESUMEN

Humic acids isolated by sodium pyrophosphate extraction from various types of peat activate macrophages in the classical proinflammatory pathway and stimulate nitric oxide production by these cells. This effect is mediated by activation of intracellular signaling pathways involving MAPK p38, PI3K, MEK 1/2 kinase, cAMP, and NF-κB via TLR-2 and TLR-4 receptors.


Asunto(s)
Sustancias Húmicas , Suelo , Activación de Macrófagos , Óxido Nítrico Sintasa de Tipo II/metabolismo , Transducción de Señal , FN-kappa B/metabolismo , Óxido Nítrico/metabolismo , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo , Lipopolisacáridos/farmacología
13.
Environ Res ; 203: 111870, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34390719

RESUMEN

Ferrihydrite (Fh), a precursor of more crystalline Fe (hydr)oxides, exhibits decent catalytic behavior; however, the instability of its amorphous structure limits its engineering applications. Siliceous ferrihydrite (FhSi) was readily synthesized in this study by co-precipitation. The formation of Fe-O-Si linkages did not alter the amorphous state of pure Fh, but increased the surface area (SBET), reduced the point of zero charge (pHZPC), and prevented the leaching of more iron. X-ray diffraction, Mössbauer and pyridine-Fourier transform infrared (FTIR) spectroscopies, and potentiometric titration revealed the presence of silicon-occupied portions of growth sites on the Fh surface, which increased the coordination symmetry around the Fe atom and inhibited the transition of Fh to more stable crystalline Fe (hydr)oxides during repeated use. Meanwhile, the density of surface hydroxyl groups (Ds) and the total acid content of the catalytic system after five cycles of catalytic ozonation were 56.75 % and 63.58 % higher than those of freshly prepared system, thereby benefiting the catalysis of ozone for generating ·OH. In addition, the lower pHZPC of the FhSi/O3 system compared to that of the Fh/O3 system promoted the generation of neutral surface-hydroxyl species on the surface of FhSi, which enabled a decent catalytic performance in alkaline solutions, regardless of the catalytic cycle. Moreover, the removal of humic acids (HA) followed a hydroxy radical reaction, which involved self-decomposition (14.15 %), catalytic ozonation (21.58 %), and peroxone and Fenton-like reactions (64.27 %).


Asunto(s)
Ozono , Contaminantes Químicos del Agua , Catálisis , Compuestos Férricos , Sustancias Húmicas , Contaminantes Químicos del Agua/análisis
14.
Appl Microbiol Biotechnol ; 106(19-20): 6833-6845, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-36104543

RESUMEN

Combinations of various strategic approaches to the suppression of methanogenesis and the formation of biogas with a simultaneous decrease in the ratio of methane in its composition were investigated. Introduction of methanogenesis suppressors such as redox derivatives of humic acids, potassium persulfate (K2S2O8), possessing oxidizing and electron acceptor properties, enzyme hexahistidine-containing organophosphorus hydrolase with high lactonase activity and polypeptide antimicrobial agent bacitracin into the media with anaerobic consortia were studied. The effect of these substances was directed at various participants of the natural methanogenic consortium, as well as on the biochemical processes carried out by them. The use of K2S2O8 together with bacitracin provided maximum and almost complete suppression of CH4 production. The measured concentration of intracellular adenosine triphosphate has shown that viability of cells in the consortium remained almost the same, whereas their metabolic activity decreased. Various combinations of the above-mentioned suppressors provided different degrees of methanogenesis suppression, but redox agents played a key role in all the cases studied. Based on the accumulated data, combining suppressors in different concentrations can be used to manage the methanogenesis (efficiency and velocity of its decrease) in media with anaerobic consortia. KEY POINTS: • Various strategies for suppression of the methanogenesis were combined. • The enzyme His6-OPH was firstly used for quorum quenching in methanogenic consortium. • Velocity of methanogenesis decrease can be managed by combinations of suppressors.


Asunto(s)
Biocombustibles , Sustancias Húmicas , Adenosina Trifosfato , Arildialquilfosfatasa , Bacitracina , Humanos , Metano/metabolismo
15.
Bioprocess Biosyst Eng ; 45(7): 1223-1235, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35716218

RESUMEN

The bioconversion of coal at ambient conditions is a promising technology for coal processing. However, there are few examples of the optimization of processes for industrial-scale use. In this work, the optimization of process parameters affecting lignite bioconversion by an isolated fungus WF8 using an artificial neural network (ANN) combined with a genetic algorithm (GA) was carried out for modeling of humic acids (HAs) yield and parameters. Kinetic models were used to understand the release characteristics of HAs from the bioconversion of lignite. The results of the present work indicate that the optimal process parameters (OPP) are 29 °C, initial pH of 7, 180 rpm, 0.6 mmol·L-1 of CuSO4, 0.4 mmol L-1 of MnSO4, and 6.4 µmol·L-1 of veratryl alcohol (VA). The predicted experimental data obtained by ANN is similar to the actual and the significant correlation coefficient value (R2) of 0.99 indicates that ANN has good predictability. The actual yield of HAs are 5.17 mg·mL-1. During bioconversion, the fungus WF8 could loosen and attack the structure of lignite. The release of HAs produced by bioconversion of lignite under the OPP via diffusion and swelling is fit to zero-order model independent on concentration. This provides support for the industrial bioconversion of lignite.


Asunto(s)
Carbón Mineral , Sustancias Húmicas , Carbón Mineral/análisis , Difusión , Sustancias Húmicas/análisis , Cinética , Redes Neurales de la Computación
16.
J Environ Manage ; 314: 115046, 2022 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-35468432

RESUMEN

The application of clay minerals facilitates the bioavailability of heavy metals and the humification in livestock manure composting. However, whether the humification plays a critical role in the bioavailability of heavy metals is still unclear. Here, with the addition of sepiolite (SEP), the fractions of Cu and Zn, and the spectral characteristics of humic acids (HAs) during aerobic pig manure composting were investigated. The SEP-amended composting had a decreased peak temperature and an increased electrical conductivity, regardless of the SEP dosage. The seed germination index increased by 15.9 ± 0.5% (p < 0.05) with the appropriate dosage of SEP (6%), indicating a higher maturity and a lower phytotoxicity of the SEP-amended compost. The addition of SEP reduced the water-extractable organic matter (WEOM) content and increased the percentage of HAs by 2.8-10.7%. More interestingly, during SEP-amended composting, the reducible fraction of heavy metals was transformed into the oxidizable fraction, and the bioavailability of Cu and Zn decreased by 11.0-15.9% and 15.4-26.5%, respectively. Ultraviolet-visible (UV-vis) spectra and fluorescence spectra analyses showed that the SUVA254 and complex fluorescent components of HAs in the SEP-amended composting increased by 4.4-15.8% and 1.2-9.0%, respectively. Nuclear magnetic resonance (NMR) further confirmed that the addition of SEP increased the aromatic index and percentage of carbonyl-carboxyl C of HAs by 3.4-8.3% and 4.6-5.7%, respectively. The redundancy analyses (RDA) described the SUVA254, aromatic index and carbonyl-carboxyl C of HAs had a strong positive correlation with the oxidizable fraction of heavy metals, which was further confirmed by variance partitioning analysis (VPA). Overall, this work suggested that the HAs structure play an important role in the bioavailability of Cu and Zn during SEP-amended composting, potentially providing safe organic fertilizer.


Asunto(s)
Compostaje , Metales Pesados , Animales , Disponibilidad Biológica , Sustancias Húmicas , Silicatos de Magnesio , Estiércol , Metales Pesados/química , Suelo , Porcinos , Zinc/química
17.
Molecules ; 27(3)2022 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-35164280

RESUMEN

Humic acids are known as natural substances of a supramolecular nature. Their self-assembly ability can affect the migration of heavy metals and other pollutants in nature. The formation of metal-humic complexes can decrease their mobility and bioavailability. This study focuses on metal ions diffusion and immobilization in humic hydrogels. Humic acids were purchased from International Humic Substances Society (isolated from different matrices-peat, soil, leonardite, water) and extracted from lignite mined in Czech Republic. Copper(II) ions were chosen as a model example of reactive metals for the diffusion experiments. The model of instantaneous planar source was used for experimental data obtained from monitoring the time development of copper(II) ions distribution in hydrogel. The effective diffusion coefficients of copper(II) ions showed the significant dependence on reaction ability of humic hydrogels. Lower amounts of the acidic functional groups caused an increase in the effective diffusion coefficient. In general, diffusion experiments seem to act as a valuable method for reactivity mapping studies on humic substances.

18.
Environ Monit Assess ; 194(10): 749, 2022 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-36070025

RESUMEN

The study focuses on the comprehensive research of geochemical and environmental roles of humic acids isolated from sediments of the urbanized lakes of Kola Peninsula, the Arctic. The sediments were collected from 5 water bodies located in the different parts of Murmansk city. The elemental analysis (C, H, N, and O percentage) of the samples was conducted. The molecular structure of the acids was investigated using solid-state CP/MAS 13C-NMR and FTIR spectroscopy methods. The findings revealed the specific geochemical and environmental features of the sediment humic acids in the urbanized aquatic ecosystems of the Arctic region. The process of humification in the studied lakes is slowed down due to cold climatic conditions and the high level of the pollution of the water bodies. The molecules of the humic acids are immature and high-oxygen. Therefore, on the one hand, they can actively leach the toxic metals from the components of the sediments. On the other hand, despite the relatively low content of chelate-forming groups in the structure of the humic acids, the stable organometallic compounds form due to high percentage of dispersed organic matter in the sediments and structural flexibility of the molecules of the acids. Furthermore, the geochemical composition of the sediments and their enrichment by the trace elements and hydrocarbons significantly influence on the character of the interaction between metals and humic acids.


Asunto(s)
Sustancias Húmicas , Lagos , Ecosistema , Monitoreo del Ambiente , Sustancias Húmicas/análisis , Lagos/análisis , Agua/análisis
19.
Bull Exp Biol Med ; 172(3): 324-327, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-35001314

RESUMEN

The course administration of humic acids isolated by the sodium pyrophosphate method from pine-sphagnum-cotton sedge peat reduced the general anaphylaxis reaction in mice and guinea pigs immunized with ovalbumin and decreased serum content of IgG1 and IgE in mice. The serum from mice treated with humic acids and sensitized with ovalbumin did not increase the rate of degranulation of mast cells isolated from intact Wistar rats in the presence of ovalbumin in comparison with the serum of control animals.


Asunto(s)
Antialérgicos , Sphagnopsida , Animales , Antialérgicos/farmacología , Degranulación de la Célula , Cobayas , Sustancias Húmicas , Inmunoglobulina E , Mastocitos , Ratones , Ovalbúmina , Ratas , Ratas Wistar , Suelo
20.
Bull Exp Biol Med ; 174(2): 236-240, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36598668

RESUMEN

The course administration of humic acids isolated with sodium pyrophosphate from raised bog sphagnum peat reduces the parameters of a Th1-type immune response in C57BL/6 mice, the severity of an anaphylactic shock in outbred CD1 mice, and degranulation of mast cells after their immunization with ovalbumin. The addition of humic acids increases the stimulated production of IL-4, IL-10 and reduces the production of IL-2, IFNγ by peripheral blood mononuclear cells of healthy donors.


Asunto(s)
Sustancias Húmicas , Sphagnopsida , Ratones , Animales , Sustancias Húmicas/análisis , Suelo , Leucocitos Mononucleares/química , Humedales , Ratones Endogámicos C57BL , Inmunidad , Células Th2 , Citocinas , Células TH1
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