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Enzyme and Microbial Technology Jan 20232,5-Furandicarboxylic acid (FDCA) can be used for synthesis of various polyesters and polyamides. It can be produced from oxidation of 5-hydroxymethylfurfural (HMF), a...
2,5-Furandicarboxylic acid (FDCA) can be used for synthesis of various polyesters and polyamides. It can be produced from oxidation of 5-hydroxymethylfurfural (HMF), a biomass-based platform chemical. In this work, a new catalyst CotA laccase/TEMPO/catalase has been presented and used for efficient and selective oxidation of HMF to FDCA. Dioxygen O, which is in-situ generated from the decomposition of HO by catalase, is used as the oxidant. In comparison to using ambient air as the oxidant, using the in-situ generated O as the oxidant has significantly increased the catalytic efficiency. Dioxygen O can be generated in a convenient and easy way using clean HO as the source. It has been found that continuous generation of O is essential, and over generation of O is not necessary because of the limitation of the O diffusion into the inner space of CotA laccase. It has been demonstrated that, by coupling with the electron transfer mediator TEMPO and catalase, the bacterial laccase can efficiently oxidize HMF to produce FDCA.
Topics: Laccase; Catalase; Hydrogen Peroxide; Furans; Oxygen; Oxidants
PubMed: 36279638
DOI: 10.1016/j.enzmictec.2022.110144 -
Environmental Science & Technology Nov 2020Dissolved Mn(III) species have been recognized as a significant form of Mn in redox transition environments, but a holistic understanding of their geochemical properties...
Dissolved Mn(III) species have been recognized as a significant form of Mn in redox transition environments, but a holistic understanding of their geochemical properties still lacks the characterization of their reactivity as reductants. Through using PbO as a surrogate oxidant and pyrophosphate (PP) as a model ligand, we evaluated the thermodynamic and kinetic constrains of dissolved Mn(III) oxidation under environmentally relevant pH. Without disproportionation, Mn(III) complexes could be directly oxidized by PbO to produce Mn oxides. The reaction rates decreased with increasing PP:Mn(III) ratio and became negligible when the ratio was above a threshold value. Particulate manganite could also be oxidized by PbO with detectable production of Pb(II). The favorability of Mn(III) oxidation by PbO as a function of the PP:Mn ratio could be predicted by the stability constant of the Mn(III)-PP complex. We developed kinetic models that couple multiple pathways of Mn oxidation by PbO to simulate the dynamics of Pb release, loss of dissolved Mn, as well as Mn(III) production and consumption. Beyond the context of Mn geochemistry, the interactions between Pb and various Mn species, including its trivalent forms, may also have important implications to the water quality in lead service lines within distribution systems.
Topics: Lead; Manganese; Manganese Compounds; Oxidants; Oxidation-Reduction; Oxides
PubMed: 33064452
DOI: 10.1021/acs.est.0c05459 -
Environmental Science & Technology Jan 2024In situ chemical oxidation (ISCO) using peroxydisulfate has become more popular in the remediation of soils and shallow groundwater contaminated with organic chemicals.... (Review)
Review
In situ chemical oxidation (ISCO) using peroxydisulfate has become more popular in the remediation of soils and shallow groundwater contaminated with organic chemicals. Researchers have studied the chemistry of peroxydisulfate and the oxidative species produced upon its decomposition (i.e., sulfate radical and hydroxyl radical) for over five decades, describing reaction kinetics, mechanisms, and product formation in great detail. However, if this information is to be useful to practitioners seeking to optimize the use of peroxydisulfate in the remediation of hazardous waste sites, the relevant conditions of high oxidant concentrations and the presence of minerals and solutes that affect radical chain reactions must be considered. The objectives of this Review are to provide insights into the chemistry of peroxydisulfate-based ISCO that can enable more efficient operation of these systems and to identify research needed to improve understanding of system performance. By gaining a deeper understanding of the underlying chemistry of these complex systems, it may be possible to improve the design and operation of peroxydisulfate-based ISCO remediation systems.
Topics: Oxides; Oxidation-Reduction; Oxidants; Minerals; Soil; Water Pollutants, Chemical; Groundwater
PubMed: 38110187
DOI: 10.1021/acs.est.3c07409 -
Chemosphere Aug 2023To ascertain the reaction variables on o-chloroaniline (o-ClA) mineralization, total nitrogen (TN) removal rate, and N-species distribution, o-ClA was subjected to...
To ascertain the reaction variables on o-chloroaniline (o-ClA) mineralization, total nitrogen (TN) removal rate, and N-species distribution, o-ClA was subjected to catalytic supercritical water oxidation (CSCWO) in a fused quartz tube reactor (FQTR). The findings demonstrated that when the temperature, reaction time, and excess oxidant were 400 °C, 90 min, and 150%, respectively, the mineralization rate of o-ClA could reach more than 95%. Moreover, potential degradation pathways of o-ClA in supercritical water oxidation (SCWO) was proposed according to the GC-MS results. TN removal rate is significantly impacted by Ru/rGO, despite the fact that its catalytic effect on the mineralization of o-ClA was not particularly noteworthy. Compared with no catalyst, the TN removal rate of o-ClA obviously increased from 44.1% to 90.3% at 400 °C, 10 wt% Ru loading, 90 min and 200% excess oxidant. In addition, N-species distribution in SCWO and CSCWO were also investigated. Results indicated that the Ru/rGO catalyst could accelerate the oxidation of ammonia-N and convert it to nitrate-N, promoting N generation. Finally, the possible N transformation pathway in CSCWO of o-ClA was proposed. As a result, this work offers fundamental information about o-ClA catalytic oxidation removal in the SCWO process.
Topics: Water; Nitrogen; Water Pollutants, Chemical; Oxidation-Reduction; Aniline Compounds; Oxidants
PubMed: 37169091
DOI: 10.1016/j.chemosphere.2023.138907 -
The Journal of Biological Chemistry Aug 2022Type I cGMP-dependent protein kinases (PKGIs) are important components of various signaling pathways and are canonically activated by nitric oxide- and natriuretic...
Type I cGMP-dependent protein kinases (PKGIs) are important components of various signaling pathways and are canonically activated by nitric oxide- and natriuretic peptide-induced cGMP generation. However, some reports have shown that PKGIα can also be activated in vitro by oxidizing agents. Using in vitro kinase assays, here, we found that purified PKGIα stored in PBS with Flag peptide became oxidized and activated even in the absence of oxidizing agent; furthermore, once established, this activation could not be reversed by reduction with DTT. We demonstrate that activation was enhanced by addition of Cu before storage, indicating it was driven by oxidation and mediated by trace metals present during storage. Previous reports suggested that PKGIα Cys, Cys, and Cys play key roles in oxidation-induced kinase activation; we show that activation was reduced by C118A or C196V mutations, although C43S PKGIα activation was not reduced. In contrast, under the same conditions, purified PKGIβ activity only slightly increased with storage. Using PKGIα/PKGIβ chimeras, we found that residues throughout the PKGIα-specific autoinhibitory loop were responsible for this activation. To explore whether oxidants activate PKGIα in H9c2 and C2C12 cells, we monitored vasodilator-stimulated phosphoprotein phosphorylation downstream of PKGIα. While we observed PKGIα Cys crosslinking in response to HO (indicating an oxidizing environment in the cells), we were unable to detect increased vasodilator-stimulated phosphoprotein phosphorylation under these conditions. Taken together, we conclude that while PKGIα can be readily activated by oxidation in vitro, there is currently no direct evidence of oxidation-induced PKGIα activation in vivo.
Topics: Cyclic GMP; Cyclic GMP-Dependent Protein Kinase Type I; Hydrogen Peroxide; Nitric Oxide; Oxidants; Oxidation-Reduction; Phosphorylation
PubMed: 35752367
DOI: 10.1016/j.jbc.2022.102175 -
Nitric Oxide : Biology and Chemistry Feb 2001An oxidizing effect of S-nitrosoglutathione toward adrenaline and its cyclic derivatives (adrenochrome and adrenolutin) is reported. The oxidation was monitored either... (Comparative Study)
Comparative Study
An oxidizing effect of S-nitrosoglutathione toward adrenaline and its cyclic derivatives (adrenochrome and adrenolutin) is reported. The oxidation was monitored either spectrophotometrically or as oxygen uptake. Adrenaline was first oxidized to adrenochrome that, after isomerization to adrenolutin, was further oxidized to products monitored as fluorescence decrease. To occur to a significant extent, this oxidation requires copper ions that, in addition to a direct effect on the oxidation of the ortho-diphenol moiety, are also able to decompose nitrosothiols, giving rise to nitric oxide. The latter, after interaction with oxygen and superoxide, produces nitrogen oxides and peroxynitrite, respectively, that are important contributors to the oxidative process. In this context, catecholamines might act as regulatory factors toward nitric oxide and its derivatives.
Topics: Adrenochrome; Copper; Epinephrine; Glutathione; Hydrogen-Ion Concentration; Indoles; Isomerism; Nitrates; Nitric Oxide; Nitroso Compounds; Oxidants; Oxidation-Reduction; Oxygen; S-Nitrosoglutathione; Spectrophotometry; Superoxides
PubMed: 11178935
DOI: 10.1006/niox.2000.0323 -
Chemosphere Jun 2011This article presents an overview with critical analysis of technical applicability of advanced oxidation process (AOP) in removing chelating agents from aqueous... (Review)
Review
This article presents an overview with critical analysis of technical applicability of advanced oxidation process (AOP) in removing chelating agents from aqueous solution. Apart from the effect of metals for chelating agents as a major influencing factor, selected information such as pH, oxidant's dose, concentrations of pollutants and treatment performance is presented. The performance of individual AOP is compared. It is evident from our literature survey that photocatalysis with UV irradiation alone or coupled with TiO(2), ozonation and Fenton's oxidation are frequently applied to mineralize target pollutants. Overall, the selection of the most suitable AOP depends on the characteristics of effluents, technical applicability, discharge standard, regulatory requirements and environmental impacts.
Topics: Chelating Agents; Hydrogen Peroxide; Iron; Oxidants; Oxidation-Reduction; Photochemical Processes; Ultraviolet Rays; Waste Disposal, Fluid; Water Pollutants, Chemical
PubMed: 21349569
DOI: 10.1016/j.chemosphere.2011.01.007 -
Organic & Biomolecular Chemistry Jul 2022We report an efficient copper-catalyzed dehydrogenation method for the synthesis of aroyl triazines from arylmethyl triazines with water in the absence of additional...
We report an efficient copper-catalyzed dehydrogenation method for the synthesis of aroyl triazines from arylmethyl triazines with water in the absence of additional oxidants or hydrogen acceptors. The use of substrates with both electron-donating and electron-withdrawing groups resulted in moderate to good yields. Using liquid chromatography-mass spectrometry, O-labeled-water reactions and hydrogen capture experiments confirmed that water was the only oxygen donor and hydrogen was the by-product. This oxidation strategy provides a new approach for the synthesis of aroyl triazines with a broad substrate scope.
Topics: Catalysis; Copper; Hydrogen; Oxidants; Triazines; Water
PubMed: 35521790
DOI: 10.1039/d2ob00582d -
Chemosphere Mar 2024The widespread use of antibiotics for the treatment of bacteriological diseases causes their accumulation at low concentrations in natural waters. This gives health... (Review)
Review
The widespread use of antibiotics for the treatment of bacteriological diseases causes their accumulation at low concentrations in natural waters. This gives health risks to animals and humans since it can increase the damage of the beneficial bacteria, the control of infectious diseases, and the resistance to bacterial infection. Potent oxidation methods are required to remove these pollutants from water because of their inefficient abatement in municipal wastewater treatment plants. Over the last three years in the period 2021-September 2023, powerful peroxymonosulfate (PMS)-based advanced oxidation processes (AOPs) have been developed to guaranty the effective removal of antibiotics in synthetic and real waters and wastewater. This review presents a comprehensive analysis of the different procedures proposed to activate PMS-producing strong oxidizing agents like sulfate radical (SO), hydroxyl radical (OH, radical superoxide ion (O), and non-radical singlet oxygen (O) at different proportions depending on the experimental conditions. Iron, non-iron transition metals, biochar, and carbonaceous materials catalytic, UVC, photocatalytic, thermal, electrochemical, and other processes for PMS activation are summarized. The fundamentals and characteristics of these procedures are detailed remarking on their oxidation power to remove antibiotics, the influence of operating variables, the production and detection of radical and non-radical oxidizing agents, the effect of added inorganic anions, natural organic matter, and aqueous matrix, and the identification of by-products formed. Finally, the theoretical and experimental analysis of the change of solution toxicity during the PMS-based AOPs are described.
Topics: Humans; Anti-Bacterial Agents; Peroxides; Oxidation-Reduction; Oxidants; Water
PubMed: 38219991
DOI: 10.1016/j.chemosphere.2024.141153 -
Water Research May 2017Ferrous-tetrapolyphosphate complexes (Fe(II)-TPP) activate oxygen and hydrogen peroxide to produce reactive oxidants capable of degrading organic compounds. In this...
Ferrous-tetrapolyphosphate complexes (Fe(II)-TPP) activate oxygen and hydrogen peroxide to produce reactive oxidants capable of degrading organic compounds. In this study, the Fe(II)-TPP/O and Fe(II)-TPP/HO systems were assessed for oxidative degradation of microcystin-LR (MC-LR), the most toxic and abundant cyanotoxin. The degradation of MC-LR was optimized for both the Fe(II)-TPP/O and Fe(II)-TPP/HO systems when the molar ratio of TPP:Fe(II) was approximately 5.7-5.9. The optimal HO dose for MC-LR degradation by Fe(II)-TPP/HO was found to be 320 μM. The Fe(II)-TPP/O and Fe(II)-TPP/HO systems exhibited two pH optima for MC-LR degradation i.e., ∼7 and 9, which can be attributed to pH-dependent reactivity changes of the resultant oxidants (most likely the ferryl-tetrapolyphostate complex, Fe(IV)-TPP). Liquid chromatography-mass spectrometry identified 22 compounds produced by the oxidation of MC-LR, including four primary oxidation products. One of the primary products, in particular, was formed via oxidative cleavage of the alkene group in the Mdha moiety of MC-LR. This compound and its secondary oxidation products are rarely found when MC-LR is transformed by other oxidants and is believed to reflect a unique reaction pathway involving Fe(IV)-TPP. Meanwhile, the hepatotoxicity of the reaction solution decreased concurrently with a decrease on MC-LR concentration.
Topics: Chromatography, Liquid; Hydrogen Peroxide; Oxidants; Oxidation-Reduction; Oxygen
PubMed: 28254645
DOI: 10.1016/j.watres.2017.02.038