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1.
ACS Synth Biol ; 13(6): 1941-1951, 2024 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-38780992

RESUMEN

Electroactive bacteria, exemplified by Shewanella oneidensis MR-1, have garnered significant attention due to their unique extracellular electron-transfer (EET) capabilities, which are crucial for energy recovery and pollutant conversion. However, the practical application of MR-1 is constrained by its EET efficiency, a key limiting factor, due to the complexity of research methodologies and the challenges associated with the practical use of gene editing tools. To address this challenge, a novel gene integration system, INTEGRATE, was developed, utilizing CRISPR-mediated transposase technologies for precise genomic insertion within the S. oneidensis MR-1 genome. This system facilitated the insertion of extensive gene segments at different sites of the Shewanella genome with an efficiency approaching 100%. The inserted cargo genes could be kept stable on the genome after continuous cultivation. The enhancement of the organism's EET efficiency was realized through two primary strategies: the integration of the phenazine-1-carboxylic acid synthesis gene cluster to augment EET efficiency and the targeted disruption of the SO3350 gene to promote anodic biofilm development. Collectively, our findings highlight the potential of utilizing the INTEGRATE system for strategic genomic alterations, presenting a synergistic approach to augment the functionality of electroactive bacteria within bioelectrochemical systems.


Asunto(s)
Sistemas CRISPR-Cas , Shewanella , Transposasas , Shewanella/genética , Shewanella/metabolismo , Transporte de Electrón , Transposasas/genética , Transposasas/metabolismo , Sistemas CRISPR-Cas/genética , Edición Génica/métodos , Genoma Bacteriano , Biopelículas , Fuentes de Energía Bioeléctrica/microbiología
2.
Water Res ; 257: 121695, 2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38723352

RESUMEN

Wolframite (FeWO4), a typical polyoxometalate, serves as an auspicious candidate for heterogeneous catalysts, courtesy of its high chemical stability and electronic properties. However, the electron-deficient surface-active Fe species in FeWO4 are insufficient to cleave H2O2 via Fe redox-mediated Fenton-like catalytic reaction. Herein, we doped Sulfur (S) atom into FeWO4 catalysts to refine the electronic structure of FeWO4 for H2O2 activation and sulfamethoxazole (SMX) degradation. Furthermore, spin-state reconstruction on S-doped FeWO4 was found to effectively refine the electronic structure of Fe in the d orbital, thereby enhancing H2O2 activation. S doping also accelerated electron transfer during the conversion of sulfur species, promoting the cycling of Fe(III) to Fe(II). Consequently, S-doped FeWO4 bolstered the Fenton-like reaction by nearly two orders of magnitude compared to FeWO4. Significantly, the developed S-doped FeWO4 exhibited a remarkable removal efficiency of approximately 100% for SMX within 40 min in real water samples. This underscores its extensive pH adaptability, robust catalytic stability, and leaching resistance. The matrix effects of water constituents on the performance of S-doped FeWO4 were also investigated, and the results showed that a certain amount of Cl-, SO42-, NO3-, HCO3- and PO43- exhibited negligible effects on the degradation of SMX. Theoretical calculations corroborate that the distinctive spin-state reconstruction of Fe center in S-doped FeWO4 is advantageous for H2O2 decomposition. This discovery offers novel mechanistic insight into the enhanced catalytic activity of S doping in Fenton-like reactions and paves the way for expanding the application of FeWO4 in wastewater treatment.


Asunto(s)
Azufre , Contaminantes Químicos del Agua , Azufre/química , Contaminantes Químicos del Agua/química , Compuestos de Tungsteno/química , Peróxido de Hidrógeno/química , Catálisis , Purificación del Agua/métodos , Oxidación-Reducción , Hierro/química
3.
Nat Commun ; 15(1): 4365, 2024 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-38778052

RESUMEN

Biotic-abiotic hybrid photocatalytic system is an innovative strategy to capture solar energy. Diversifying solar energy conversion products and balancing photoelectron generation and transduction are critical to unravel the potential of hybrid photocatalysis. Here, we harvest solar energy in a dual mode for Cu2-xSe nanoparticles biomineralization and seawater desalination by integrating the merits of Shewanella oneidensis MR-1 and biogenic nanoparticles. Photoelectrons generated by extracellular Se0 nanoparticles power Cu2-xSe synthesis through two pathways that either cross the outer membrane to activate periplasmic Cu(II) reduction or are directly delivered into the extracellular space for Cu(I) evolution. Meanwhile, photoelectrons drive periplasmic Cu(II) reduction by reversing MtrABC complexes in S. oneidensis. Moreover, the unique photothermal feature of the as-prepared Cu2-xSe nanoparticles, the natural hydrophilicity, and the linking properties of bacterium offer a convenient way to tailor photothermal membranes for solar water production. This study provides a paradigm for balancing the source and sink of photoelectrons and diversifying solar energy conversion products in biotic-abiotic hybrid platforms.


Asunto(s)
Biomineralización , Cobre , Agua de Mar , Shewanella , Energía Solar , Shewanella/metabolismo , Cobre/química , Cobre/metabolismo , Agua de Mar/microbiología , Agua de Mar/química , Salinidad , Purificación del Agua/métodos , Nanopartículas/química , Catálisis/efectos de la radiación
4.
ACS Nano ; 18(22): 14617-14628, 2024 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-38759100

RESUMEN

Nanoagrochemicals present promising solutions for augmenting conventional agriculture, while insufficient utilization of nanobiointerfacial interactions hinders their field application. This work investigates the multiscale physiochemical interactions between nanoagrochemicals and rice (Oryza sativa L.) leaves and devises a strategy for elevating targeting efficiency of nanoagrochemicals and stress resilience of rice. We identified multiple deposition behaviors of nanoagrochemicals on hierarchically structured leaves and demonstrated the crucial role of leaf microarchitectures. A transition from the Cassie-Baxter to the Wenzel state significantly changed the deposition behavior from superlattice assembly, ring-shaped aggregation to uniform monolayer deposition. By fine-tuning the formulation properties, we achieved a 415.9-fold surge in retention efficiency, and enhanced the sustainability of nanoagrochemicals by minimizing loss during long-term application. This biointerface design significantly relieved the growth inhibition of Cd(II) pollutant on rice plants with a 95.2% increase in biomass after foliar application of SiO2 nanoagrochemicals. Our research elucidates the intricate interplay between leaf structural attributes, nanobiointerface design, and biological responses of plants, fostering field application of nanoagrochemicals.


Asunto(s)
Oryza , Hojas de la Planta , Oryza/metabolismo , Oryza/química , Hojas de la Planta/química , Hojas de la Planta/metabolismo , Estrés Fisiológico/efectos de los fármacos , Dióxido de Silicio/química , Cadmio/química , Nanoestructuras/química
5.
ACS Appl Bio Mater ; 7(3): 1801-1809, 2024 03 18.
Artículo en Inglés | MEDLINE | ID: mdl-38416780

RESUMEN

Bacterial nanocellulose (BNC) is an attractive green-synthesized biomaterial for biomedical applications and various other applications. However, effective engineering of BNC production has been limited by our poor knowledge of the related metabolic processes. In contrast to the traditional perception that genome critically determines biosynthesis behaviors, here we discover that the glucose metabolism could also drastically affect the BNC synthesis in Gluconacetobacter hansenii. The transcriptomic profiles of two model BNC-producing strains, G. hansenii ATCC 53582 and ATCC 23769, which have highly similar genomes but drastically different BNC yields, were compared. The results show that their BNC synthesis capacities were highly related to metabolic activities such as ATP synthesis, ion transport protein assembly, and carbohydrate metabolic processes, confirming an important role of metabolism-related transcriptomes in governing the BNC yield. Our findings provide insights into the microbial biosynthesis behaviors from a transcriptome perspective, potentially guiding cellular engineering for biomaterial synthesis.


Asunto(s)
Perfilación de la Expresión Génica , Transcriptoma , Transcriptoma/genética , Materiales Biocompatibles , Ingeniería Celular , Transporte Iónico
6.
J Hazard Mater ; 468: 133791, 2024 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-38367438

RESUMEN

The prevalence of antibiotic resistance genes (ARGs) in municipal wastewater treatment plants (MWTPs) has emerged as a significant environmental concern. Despite advanced treatment processes, high levels of ARGs persist in the secondary effluent from MWTPs, posing ongoing environmental risks. This study explores the potential of gamma-ray irradiation as a novel approach for sterilizing antibiotic-resistant bacteria (ARB) and reducing ARGs in MWTP secondary effluent. Our findings reveal that gamma-ray irradiation at an absorbed dose of 1.6 kGy effectively deactivates all culturable bacteria, with no subsequent revival observed after exposure to 6.4 kGy and a 96-h incubation in darkness at room temperature. The removal efficiencies for a range of ARGs, including tetO, tetA, blaTEM-1, sulI, sulII, and tetW, were up to 90.5% with a 25.6 kGy absorbed dose. No resurgence of ARGs was detected after irradiation. Additionally, this study demonstrates a considerable reduction in the abundances of extracellular ARGs, with the transformation efficiencies of extracellular tetracycline and sulfadiazine resistance genes decreasing by 56.3-81.8% after 25.6 kGy irradiation. These results highlight the effectiveness of gamma-ray irradiation as an advanced and promising method for ARB sterilization and ARG reduction in the secondary effluent of MWTPs, offering a potential pathway to mitigate environmental risks associated with antibiotic resistance.


Asunto(s)
Genes Bacterianos , Aguas Residuales , Antagonistas de Receptores de Angiotensina/farmacología , Inhibidores de la Enzima Convertidora de Angiotensina/farmacología , Antibacterianos/farmacología , Bacterias/genética , Farmacorresistencia Microbiana/genética
7.
Environ Sci Technol ; 58(1): 795-804, 2024 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-38095914

RESUMEN

Iron plaque, as a natural barrier between rice and soil, can reduce the accumulation of pollutants in rice by adsorption, contributing to the safe production of rice in contaminated soil. In this study, we unveiled a new role of iron plaque, i.e., producing hydroxyl radicals (·OH) by activating root-secreted oxygen to degrade pollutants. The ·OH was produced on the iron plaque surface and then diffused to the interfacial layer between the surface and the rhizosphere environment. The iron plaque activated oxygen via a successive three-electron transfer to produce ·OH, involving superoxide and hydrogen peroxide as the intermediates. The structural Fe(II) in iron plaque played a dominant role in activating oxygen rather than the adsorbed Fe(II), since the structural Fe(II) was thermodynamically more favorable for oxygen activation. The oxygen vacancies accompanied by the structural Fe(II) played an important role in oxygen activation to produce ·OH. The interfacial ·OH selectively degraded rhizosphere pollutants that could be adsorbed onto the iron plaque and was less affected by the rhizosphere environments than the free ·OH. This study uncovered the oxidative role of iron plaque mediated by its produced ·OH, reshaping our understanding of the role of iron plaque as a barrier for rice.


Asunto(s)
Contaminantes Ambientales , Oryza , Contaminantes del Suelo , Hierro/química , Contaminantes Ambientales/análisis , Radical Hidroxilo/análisis , Radical Hidroxilo/metabolismo , Rizosfera , Raíces de Plantas/química , Raíces de Plantas/metabolismo , Suelo/química , Compuestos Ferrosos/análisis , Compuestos Ferrosos/metabolismo , Oxígeno/análisis
8.
Environ Sci Technol ; 57(51): 21835-21845, 2023 Dec 26.
Artículo en Inglés | MEDLINE | ID: mdl-38085064

RESUMEN

The persistence of extracellular antibiotic resistance genes (ARGs) in aquatic environments has attracted increasing attention due to their potential threat to public health and the environment. However, the fate of extracellular ARGs in receiving water remains largely unknown. This study investigated the influence of hematite nanoparticles, a widespread natural mineral, on the photodegradation of extracellular ARGs in river water. Results showed that under exposure to visible light, hematite nanoparticles, at environmental concentrations, resulted in a 3-5 orders of magnitude reduction in extracellular ARGs. This photodegradation of extracellular ARGs is shown to be facet-dependent; the (001) facet of hematite demonstrates a higher removal rate than that of the (100) facet, which is ascribed to its enhanced adsorption capability and higher hydroxyl radical (•OH) production. Density functional theory (DFT) calculations corroborate this finding, indicating elevated iron density, larger adsorption energy, and lower energy barrier of •OH formation on the (001) facet, providing more active sites and •OH generation for extracellular ARG interaction. Gel electrophoresis and atomic force microscopy analyses further confirm that the (001) facet causes more substantial damage to extracellular ARGs than the (100) facet. These findings pave the way for predicting the photodegradation efficiency of hematite nanoparticles with varied facets, thereby shedding light on the inherent self-purification capacity for extracellular ARGs in both natural and engineered aquatic environments.


Asunto(s)
Antibacterianos , Aguas Residuales , Antibacterianos/farmacología , Genes Bacterianos , Agua , Farmacorresistencia Microbiana/genética , Nanopartículas Magnéticas de Óxido de Hierro
10.
Environ Int ; 178: 108121, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37544266

RESUMEN

Compared to individual UV or chlorine disinfection, the combined UV and chlorine (i.e., UV/chlorine) can substantially promote the degradation of antibiotic resistance genes (ARGs) in the effluent by generating radicals. However, the mechanisms of ARG degradation induced by radicals during UV/chlorine treatment remain largely unknown, limiting further enhancement of ARG degradation by process optimization. Herein, we aimed to uncover the role of different radicals in ARG degradation and the molecular mechanisms of ARG degradation by radicals in UV/chlorine process. The ClO was proven to be responsible for the enhanced ARG degradation during UV/chlorine treatment, while the other radicals (OH, Cl, and Cl2-) played a minor role. This is because ClO possessed both high steady-state concentration and high reactivity toward ARGs (rate constant: 4.29 × 1010 M-1 s-1). The ClO might collaborate with free chlorine to degrade ARG. The ClO degraded ARGs by selectively attacking guanine and thymine but failed to induce strand breakage, while chlorine could break the strand of ARGs. Ultimately, ClO cooperated with chlorine to degrade ARGs quickly by hydroxylation and chlorination of bases and produce many chlorine- and nitrogen-containing products as revealed by high-resolution mass spectrometry. The uncovered degradation mechanisms of ARGs by UV/chlorine provide useful guidelines for process optimization to achieve deep removal of effluent ARGs.


Asunto(s)
Compuestos de Cloro , Contaminantes Químicos del Agua , Purificación del Agua , Antibacterianos , Cloro , Farmacorresistencia Microbiana/genética , Desinfección , Cloruros , Purificación del Agua/métodos , Rayos Ultravioleta , Cinética , Contaminantes Químicos del Agua/análisis , Oxidación-Reducción
11.
Water Res X ; 20: 100193, 2023 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-37601243

RESUMEN

The efficient generation and utilization of ROSs is a key step in determining the achievement of safe drinking water by photocatalytic bacterial inactivation technology. Although graphitic carbon nitride (g-C3N4) serves as a green and promising photocatalyst for water disinfection, insufficient bacterial capturing capacity and serious charge recombination of pristine g-C3N4 extremely restrict its bactericidal activity. Herein, we develop a facile thermal exfoliation and thermal polymerization method to prepare the nitrogen-defective ultrathin g-C3N4 nanosheets (DUCN-500). Our results showed that ultrathin nanosheet structure greatly enhanced bacterial capturing capacity of g-C3N4 to increase the utilization efficiency of ROS, which contributed to the performance of DUCN-500 greatly outperforming bulk g-C3N4. The nitrogen defects increased ROS generation (·O2- and H2O2) by approximately 4.6 times, which was attributed to negative shift of the conduction band potential and rapid separation of charge carriers. The DUCN-500 could rapidly and completely inactivate Escherichia coli and Bacillus subtilis in real sewage under simulated solar irradiation, accompanied by good anti-interference capability and stability. Additionally, bacterial morphology destruction, the loss of antioxidant enzyme activity and the leakage of protein were proven to be the main mechanisms of photocatalytic sterilization. This study offers new insight into the rational design of efficient g-C3N4-based photocatalysts for water disinfection.

12.
Water Res ; 242: 120251, 2023 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-37356160

RESUMEN

Micro(nano)plastics widely detected in aquatic environments have caused serious threat to water quality security. However, as a potential important source of micro(nano)plastics in surface water during the COVID-19 pandemic, the ecological risks of face mask waste to aquatic environments remain poorly understood. Herein, we comprehensively characterized the micro(nano)plastics and organic compounds released from four daily used face masks in aqueous environments and further evaluated their potential impacts on aquatic ecosystem safety by quantitative genotoxicity assay. Results from spectroscopy and high-resolution mass spectrum showed that plastic microfibers/particles (∼11%-83%) and leachable organic compounds (∼15%-87%) were dominantly emitted pollutants, which were significantly higher than nanoplastics (< ∼5%) based on mass of carbon. Additionally, a toxicogenomics approach using green fluorescence protein-fused whole-cell array revealed that membrane stress was the primary response upon the exposure to micro(nano)plastics, whereas the emitted organic chemicals were mainly responsible for DNA damage involving most of the DNA repair pathways (e.g., base/nucleotide excision repair, mismatch repair, double-strand break repair), implying their severe threat to membrane structure and DNA replication of microorganisms. Therefore, the persistent release of discarded face masks derived pollutants might exacerbate water quality and even adversely affect aquatic microbial functions. These findings would contribute to unraveling the potential effects of face mask waste on aquatic ecosystem security and highlight the necessity for more developed management regulations in face mask disposal.


Asunto(s)
COVID-19 , Contaminantes Ambientales , Contaminantes Químicos del Agua , Humanos , Ecosistema , Plásticos/toxicidad , Máscaras , Pandemias , Toxicogenética , Compuestos Orgánicos , Contaminantes Químicos del Agua/análisis
13.
J Hazard Mater ; 455: 131587, 2023 08 05.
Artículo en Inglés | MEDLINE | ID: mdl-37172383

RESUMEN

Discarded face masks from the global COVID-19 pandemic have contributed significantly to plastic pollution in surface water, whereas their potential as a reservoir for aquatic pollutants is not well understood. Herein, we conducted a field experiment along a human-impacted urban river, investigating the variations of antibiotic resistance genes (ARGs), pathogens, and water-borne contaminants in commonly-used face masks. Results showed that high-biomass biofilms formed on face masks selectively enriched more ARGs than stone biofilm (0.08-0.22 vs 0.07-0.15 copies/16 S rRNA gene copies) from bulk water, which mainly due to unique microbial communities, enhanced horizontal gene transfer, and selective pressure of accumulated contaminants based on redundancy analysis and variation partitioning analysis. Several human opportunistic pathogens (e.g., Acinetobacter, Escherichia-Shigella, Bacillus, and Klebsiella), which are considered potential ARG carriers, were also greatly concentrated in face-mask biofilms, imposing a potential threat to aquatic ecological environment and human health. Moreover, wastewater treatment plant effluents, as an important source of pollutants to urban rivers, further aggravated the abundances of ARGs and opportunistic pathogens in face-mask biofilms. Our findings demonstrated that discarded face masks provide a hotspot for the proliferation and spread of ARGs and pathogens in urban water, highlighting the urgent requirement for implementing stricter regulations in face mask disposal.


Asunto(s)
COVID-19 , Genes Bacterianos , Humanos , Máscaras , Ríos , Antibacterianos/farmacología , Antibacterianos/análisis , Pandemias , Agua , Biopelículas
14.
J Hazard Mater ; 451: 131104, 2023 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-36870127

RESUMEN

Phosphonates, as a kind of important organic phosphorus in wastewater, should be removed in terms of their environmental risks. Unfortunately, traditional biological treatments fail to remove phosphonates effectively due to their biological inertness. The reported advanced oxidation processes (AOPs) usually require pH adjustment or coupling with other technologies to achieve high removal efficiency. Thus, a simple and efficient method for phosphonate removal is urgently needed. Herein, ferrate was found to remove phosphonates effectively in one-step under near-neutral circumstances by coupling oxidation and in-situ coagulation. Nitrilotrimethyl-phosphonic acid (NTMP), a typical phosphonate, could be efficiently oxidized by ferrate to release phosphate. The fraction of phosphate release increased with increasing ferrate dosage and reached 43.1% when 0.15 mM ferrate was added. Fe(VI) was responsible for NTMP oxidation, while Fe(V), Fe(IV) and ⋅OH played a minor role. Ferrate-induced phosphate release facilitated total phosphorus (TP) removal, because the phosphate is more easily removed via ferrate-resultant Fe(III) coagulation than the phosphonates. The coagulation removal of TP could reach up to 90% within 10 min. Furthermore, ferrate exerted high removal efficiencies for other commonly used phosphonates with approximately or up to 90% TP removal. This work provides a one-step efficient method to treat phosphonate-containing wastewaters.

15.
Water Res ; 232: 119668, 2023 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-36731205

RESUMEN

Although surface-enhanced Raman spectroscopy (SERS) offers a promising technology for sensitive detection of environmental pollutants in natural waters, its performance can be greatly affected by the environmental matrix. The lack of identification of the origin and the underlying mechanism of matrix effect hinders the application of SERS in practical environmental analysis. Herein, with silver nanoparticles (AgNPs) as a solution-based SERS substrate, the matrix effect from environmental waters on SERS analysis and the underlying mechanisms were investigated. It was found that natural water matrix could deteriorate SERS performance and cause artefacts in SERS spectra. Among various aqueous components, natural organic matter (NOM), including humic substances and proteins, mainly contributed to the matrix effect on SERS detection, while polysaccharides or inorganic ions had minor influence. The matrix effect from NOM was found to be prevalent for different analytes and SERS substrates. The mechanism of the matrix effect from NOM in the ternary system of analyte, NOM, and nanoparticles was investigated through three mutual interactions. The microheterogeneous repartition of analytes by NOM, other than the formation of NOM-corona or competitive adsorption between NOM and analytes on nanoparticles, was found to play the dominating role in interfering with SERS detection. This work illuminates the origin and underlying mechanisms of the matrix effect, which will promote the practical application of SERS technology in environmental analysis.


Asunto(s)
Contaminantes Ambientales , Nanopartículas del Metal , Espectrometría Raman/métodos , Nanopartículas del Metal/química , Contaminantes Ambientales/análisis , Plata/química , Adsorción , Agua
16.
Adv Sci (Weinh) ; 10(3): e2205681, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36446629

RESUMEN

Learning and studying the structure-activity relationship in the bio-enzymes is conducive to the design of nanozymes for energy and environmental application. Herein, Fe single-atom nanozymes (Fe-SANs) with Fe-N5 site, inspired by the structure of cytochromes P450 (CYPs), are developed and characterized. Similar to the CYPs, the hyperoxide can activate the Fe(III) center of Fe-SANs to generate Fe(IV)O intermediately, which can transfer oxygen to the substrate with ultrafast speed. Particularly, using the peroxymonosulfate (PMS)-activated Fe-SANs to oxidize sulfamethoxazole, a typical antibiotic contaminant, as the model hyperoxides activation reaction, the excellent activity within 284 min-1 g-1 (catalyst) mmol-1 (PMS) oxidation rate and 91.6% selectivity to the Fe(IV)O intermediate oxidation are demonstrated. More importantly, instead of promoting PMS adsorption, the axial N ligand modulates the electron structure of FeN5 SANs for the lower reaction energy barrier and promotes electron transfer to PMS to produce Fe(IV)O intermediate with high selectivity. The highlight of the axial N coordination in the nanozymes in this work provides deep insight to guide the design and development of nanozymes nearly to the bio-enzyme with excellent activity and selectivity.


Asunto(s)
Compuestos Férricos , Peróxidos , Ligandos , Oxidación-Reducción
17.
Environ Sci Technol ; 56(24): 17684-17693, 2022 12 20.
Artículo en Inglés | MEDLINE | ID: mdl-36455257

RESUMEN

The transformation of extracellular antibiotic resistance genes (eARGs) is largely influenced by their inevitable photodegradation in environments where they tend to be adsorbed by ubiquitous clay minerals instead of being in a free form. However, the photodegradation behaviors and mechanisms of the adsorbed eARGs may be quite different from those of the free form and still remain unclear. Herein, we found that kaolinite, a common 1:1-type clay, markedly enhanced eARG photodegradation and made eARGs undergo direct photodegradation under UVA. The decrease in the transformation efficiency of eARGs caused by photodegradation was also promoted. Spectroscopy methods combined with density functional theory calculations revealed that the Lewis acid-base interaction between P-O in eARGs and Al-OH on kaolinite delocalized electrons of eARGs, thus resulting in increased photon absorption ability of eARGs. This ultimately led to enhanced photodegradation of kaolinite-adsorbed eARGs. Additionally, divalent Ca2+ could reduce the Lewis acid-base interaction-mediated adsorption of eARGs by kaolinite, thereby weakening the enhanced photodegradation of eARGs caused by electron delocalization. In contrast, the 2:1-type clay montmorillonite without strong Lewis acid sites was unable to delocalize the electrons to enhance the photodegradation of eARGs. This work allowed us to better evaluate eARGs' fate and risk in real aqueous environments.


Asunto(s)
Antibacterianos , Caolín , Arcilla , Caolín/química , Ácidos de Lewis , Electrones , Fotólisis , Minerales/química , Farmacorresistencia Microbiana/genética , Adsorción
18.
Environ Int ; 166: 107381, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35810547

RESUMEN

The spread of antibiotics and antibiotic resistance genes (ARGs) in environments has posed potential threats to public health. Unfortunately, conventional biological wastewater treatment technologies generally show insufficient removal of antibiotics and ARGs. Bioelectrochemical systems, which can effectively degrade refractory organic pollutants via enhancing microbial metabolisms through electrochemical redox reaction, may provide an alternative for the control of antibiotics and ARGs. Herein, an anaerobic electrochemical membrane bioreactor (AnEMBR) was conducted by combining bioelectrochemical system and anaerobic membrane bioreactor to treat antibiotic-containing wastewater. The AnEMBR at open circuit showed stable CH4 production and high removal of COD and chlortetracycline (CTC) in treating 2.5-15 mg/L CTC. However, increasing CTC to 45 mg/L completely inhibited the methanogenesis of AnEMBR at open circuit. After applying external voltage in AnEMBR, the performances of AnEMBR were significantly improved (e.g., increased CH4 production and CTC removal). Moreover, CTC exposure significantly increased the relative abundances of ARGs in sludge, supernatant, and effluent in AnEMBR at open circuit. Applying voltage greatly attenuated the total relative abundances of ARGs in the supernatant and effluent of AnEMBR compared to those at open circuit. This could be attributed to the enrichment of tetracycline degradation gene tetX, which greatly enhanced the removal of CTC by the AnEMBR and thus reduced the selective pressure of CTC on the microorganisms in supernatant and effluent for ARGs proliferation. These results would provide an effective wastewater treatment technology for treating high-level antibiotic-containing wastewater to mitigate the potential risk of ARGs and antibiotics spread in receiving water body.


Asunto(s)
Antibacterianos , Clortetraciclina , Antibacterianos/farmacología , Aguas Residuales , Anaerobiosis , Genes Bacterianos , Farmacorresistencia Microbiana/genética , Reactores Biológicos , Proliferación Celular
19.
J Am Chem Soc ; 144(14): 6434-6441, 2022 04 13.
Artículo en Inglés | MEDLINE | ID: mdl-35377628

RESUMEN

The biotic-abiotic photosynthetic system integrating inorganic light absorbers with whole-cell biocatalysts innovates the way for sustainable solar-driven chemical transformation. Fundamentally, the electron transfer at the biotic-abiotic interface, which may induce biological response to photoexcited electron stimuli, plays an essential role in solar energy conversion. Herein, we selected an electro-active bacterium Shewanella oneidensis MR-1 as a model, which constitutes a hybrid photosynthetic system with a self-assembled CdS semiconductor, to demonstrate unique biotic-abiotic interfacial behavior. The photoexcited electrons from CdS nanoparticles can reverse the extracellular electron transfer (EET) chain within S. oneidensis MR-1, realizing the activation of a bacterial catalytic network with light illumination. As compared with bare S. oneidensis MR-1, a significant upregulation of hydrogen yield (711-fold), ATP, and reducing equivalent (NADH/NAD+) was achieved in the S. oneidensis MR-1-CdS under visible light. This work sheds light on the fundamental mechanism and provides design guidelines for biotic-abiotic photosynthetic systems.


Asunto(s)
Electrones , Shewanella , Transporte de Electrón , Hidrógeno , Fotosíntesis
20.
Angew Chem Int Ed Engl ; 61(26): e202200093, 2022 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-35312134

RESUMEN

A photothermal nanoconfinement reactor (PNCR) system is proposed and demonstrated by using hollow carbon nanospheres (HCNs) to enhance the performance of the chemical reaction. Under light irradiation, the local temperature of the HCN inner void space was much higher than the bulk solution temperature because the confined space concentrates heat and inhibits heat loss. Using the temperature-sensitive model reaction, peroxydisulfate (PDS) activation to oxidize micropollutant, it is shown that the degradation rate of sulfamethoxazole in the PNCR system is 7.1 times of that without nanoconfinement. It is further discovered that the high-quality local heat inside the nanoconfined space shifted the model reaction from an otherwise non-radical pathway to a radical-based pathway. This work provides an interesting strategy to produce a locally high temperature, which has a wide range of applications to energy and environmental fields.

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