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1.
Environ Sci Technol ; 2021 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-33830745

RESUMO

The ecological roles of influent microflora in activated sludge communities have not been well investigated. Herein, parallel lab-scale anoxic/aerobic (A/O) membrane bioreactors (MBRs), which were fed with raw (MBR-C) and sterilized (MBR-T) municipal wastewater, were operated. The MBRs showed comparable nitrogen removal but superior phosphorus removal in MBR-C than MBR-T over the long-term operation. The MBR-C sludge community had higher diversity and deterministic assembly than the MBR-T sludge community as revealed by 16S rRNA gene sequencing and null model analysis. Moreover, the MBR-C sludge community had higher abundance of polyphosphate accumulating organisms (PAOs) and hydrolytic/fermentative bacteria (HFB) but lower abundance of glycogen-accumulating organisms (GAOs), in comparison with MBR-T sludge. Intriguingly, the results of both the net growth rate and Sloan's neutral model demonstrated that HFB in the sludge community were generally slow-growing or nongrowing and their consistent presence in activated sludge was primarily attributed to the HFB immigration from influent microflora. Positive correlations between PAOs and HFB and potential competitions between HFB and GAOs were observed, as revealed by the putative species-species associations in the ecological networks. Taken together, this work deciphers the positive ecological roles of influent microflora, particularly HFB, in system functioning and highlights the necessity of incorporating influent microbiota for the design and modeling of A/O MBR plants.

2.
Sci Total Environ ; 776: 145858, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33640551

RESUMO

In this study, we proposed a novel IFAS-MBR with low aeration for the treatment of real municipal wastewater. With biocarriers packed in the anoxic tank, the pilot-scale IFAS-MBR operated with average dissolved oxygen concentrations of 0.56 mg/L in the oxic tank. Over 110 days of operation, highly efficient nutrient removal was achieved with the total nitrogen (TN) and phosphorus (TP) removal efficiencies of 78.1 ± 7.2% and 93.7 ± 5.8%, respectively. The average effluent concentrations of TN and TP reached 5.4 and 0.26 mg/L, respectively. Meanwhile, the removal efficiency of COD reached 95.3 ± 1.3% in the system, and the concentrations of COD decreased from 31.9 ± 3.7 (sludge supernatant) to 12.7 ± 1.6 mg/L (permeate) after membrane filtration. Microbial community analysis showed that Nitrosomonas (0.32%) and Nitrospira (1.85%) in activated sludge were the main drivers of the nitrification process, while various denitrifying bacteria in activated sludge and biofilms were responsible for nitrate reduction in the anoxic tank. Candidatus Accumulibacter (0.34%) and Dechloromonas (1.31%) primarily contributed to denitrifying phosphorus uptake in the anoxic tank. Furthermore, these organisms (i.e., core functional microbiota) exhibited stable levels over the entire operation. The highly enriched hydrolytic fermentation bacteria drove community succession, and the remarkable functional robustness of microbial communities in activated sludge and biofilms favored nutrient removal. Overall, the novel IFAS-MBR system provides an energy-efficient MBR alternative owing to its highly efficient performance and low operating costs enabled by low aeration rates and the absence of an external carbon source.


Assuntos
Microbiota , Águas Residuárias , Reatores Biológicos , Nitrogênio , Nutrientes , Fósforo , Esgotos , Eliminação de Resíduos Líquidos
3.
Artigo em Inglês | MEDLINE | ID: mdl-33557516

RESUMO

Bimetallic organic frameworks (Bi-MOFs) have been recognized as one of the most ideal precursors to construct metal oxide semiconductor (MOS) composites, owing to their high surface area, various chemical structures, and easy removal of the sacrificial MOF scaffolds through calcination. Herein, we synthesized Zn/Ni Bi-MOF for the first time via a facile ion exchange postsynthetic strategy, formed a three-dimensional framework consisting of infinite one-dimensional chains that is unattainable through the direct solvothermal approach, and then transformed the Zn/Ni Bi-MOF into a unique ZnO/NiO heterostructure through calcination. Notably, the obtained sensor based on a ZnO/NiO heterostructure exhibits an ultrahigh response of 280.2 toward 500 ppm n-propanol at 275 °C (17.2-fold enhancement compared with that of ZnO), remarkable selectivity, and a limit of detection of 200 ppb with a notable response (2.51), which outperforms state-of-the-art n-propanol sensors. The enhanced n-propanol sensing properties may be attributed to the synergistic effects of several points including the heterojunction at the interface between the NiO and ZnO nanoparticles, especially a one-dimensional chain MOF template structure as well as the chemical sensitization effect of NiO. This work provides a promising strategy for the development of a novel Bi-MOF-derived MOS heterostructure or homostructure with well-defined morphology and composition that can be applied to the fields of gas sensing, energy storage, and catalysis.

4.
Artigo em Inglês | MEDLINE | ID: mdl-32975866

RESUMO

Substrate-supported metal-organic frameworks (MOFs) films are desired to realize their potential in practical applications. Herein, a novel substrate-seeding secondary-growth strategy is developed to prepare composites of uniform MOFs films on aerogel walls. Briefly, the organic ligand is "pre-seeded" onto the aerogel walls, and then a small amount of metal-ion solution is sprayed onto the prepared aerogel. The sprayed solution diffuses along the aerogel walls to form a continuous thin layer, which confines the nucleation reaction, promoting the formation of uniform MOFs films on the aerogel walls. The whole process is simple in operation, highly efficient, and eco-friendly. The resulting hierarchical MOFs/aerogel composites have abundant accessible active sites and enable excellent mass transfer, which endows the composite with outstanding catalytic activity and stability in both liquid-phase CO2 cycloaddition and electrochemical oxygen evolution reaction (OER) process.

5.
Appl Environ Microbiol ; 86(18)2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32651202

RESUMO

Fungi are known to play important roles in pollutant transformation in activated sludge-based wastewater treatment plants (WWTPs). However, the seasonality and distributions of fungal populations in different-sized flocs have still remained largely unknown. In this study, seasonal population dynamics and community separation of fungi in a municipal WWTP across a 1-year period were investigated. We classified all taxa into six categories based on abundances to assess their roles and contributions to the whole community. The results showed that the rare taxa (<0.01%) contributed greatly to species richness (95.27%). Conversely, although low in species diversity, abundant taxa (≥1%) accounted for the majority (89.45%) of the total relative abundance, which suggested that a few core abundant fungi existed in the activated sludge ecosystem. The abundant, conditionally rare, and rare taxa contributed 30.14%, 31.11%, and 38.75%, respectively, to temporal shifts in community structure, and their abundances responded differently to environmental variables, suggesting that these three subcommunities exhibited a large difference in environmental sensitivity. Importantly, the results revealed seasonal dynamics of the whole fungal community and the subcommunities of all the microbial taxon categories, resulting in significant differences in community structures between warm and cold seasons. Furthermore, fungal diversity and the compositions of the whole community and subcommunities differed significantly among flocs of different sizes, which underlined the size-based fungal community separation in activated sludge of WWTPs. The findings of this work improved our understanding of fungal population dynamics and community separation in WWTPs.IMPORTANCE Fungi are important contributors to the various functions of activated sludge in wastewater treatment plants (WWTPs). Unlike previous studies, this work demonstrated the seasonality of the fungal community over a longer time span while it also systematically assessed the contributions of abundant, conditionally rare, and rare taxa to the whole community. Importantly, in the present study, we considered sludge flocs of a certain size range rather than the whole sludge flocs as a community. Our results revealed significant differences in fungal community structure among different-sized flocs, which supported the idea that size-based fungal community segregation is occurring in activated sludge ecosystems. The findings provide new insights into the dynamic changes or distribution of fungi in the bioaggregates of sludge flocs in WWTPs.

6.
Langmuir ; 36(26): 7392-7399, 2020 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-32493015

RESUMO

An interesting reversible shape and structure transformation between two types of two-dimensional (2D) metal-organic frameworks (MOFs) has been successfully achieved by the spray method. The ability to precisely control the morphology and structure of 2D MOFs is also developed by altering the amount of MOF precursors and reversing the spray order. Meanwhile, the mechanism of the transformation between two MOFs is studied and conversion is induced by the change of the acidity in the reaction system. In addition, the prepared non-interpenetrate CuBDC twists exhibit more remarkable catalytic performance in C-S coupling reaction than Cu(BDC)(DMF) nanosheets owing to the more unsaturated coordination copper active sites from the non-interpenetrate structure. The catalytic result reveals the relationship between structure and function.

7.
Water Res ; 181: 115915, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32485441

RESUMO

Odors from wastewater treatment plants (WWTPs) have attracted extensive attention and stringent environmental standards are more widely adopted to reduce odor emissions. Biological odor treatment methods have broader applications than the physical and chemical counterparts as they are environment-friendly, cost-effective and generate low secondary wastes. The aqueous activated sludge (AS) processes are among the most promising approaches for the prevention or end-of-pipe removal of odor emissions and have the potential to simultaneously treat odor and wastewater. However, AS deodorization biotechnologies in WWTPs still need to be further systematically summarized and categorized while in-depth discussions on the characteristics and underlying mechanisms of AS deodorization process are still lacking. Recently, considerable studies have been reported to elucidate the microbial metabolisms in odor control and wastewater treatment. This paper reviews the fundamentals, characteristics, advances and field experiences of three AS biotechnologies for odor treatment in WWTPs, i.e., AS recycling, microaeration in AS digester and AS diffusion. The underlying deodorization mechanisms of typical odors have been revealed through the summary of recent advances on multi-element conversions, metabolic interactions of bacteria, microscopic characterization and identification of functional microorganisms. Future research aspects to advance the emerging deodorization AS process, such as deodorization mechanisms, simultaneous odor and water treatment, synergistic treatment with other air emissions, are discussed.


Assuntos
Águas Residuárias , Purificação da Água , Odorantes , Reciclagem , Esgotos , Eliminação de Resíduos Líquidos
8.
Adv Mater ; 32(12): e1907569, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32027061

RESUMO

Structural color materials with reversible stimuli-responsiveness to external environment have been widely used in sensors, encryption, display, and other fields. Compared with other stimuli, visible light is highly controllable both temporally and spatially with less damage to materials, which is more suitable for structural color patterning. Herein, a new diselenide-containing shape memory material is prepared and used for creating patterns via visible light stimulus. In this system, the structural color originates from birefringence of stretched materials, whose shapes can be fixed while maintaining the mechanical stress. The fixed stress can be released by diselenide metathesis under visible light irradiation. By regulating the wavelength or irradiation time with a commercial projector, the pattern with tunable structural colors is realized and the structural color pattern can be erased and rewritten arbitrarily. During the patterning process, the optical signal is first stored as mechanical signal and then transformed back to optical signal. It is a new method for preparing visible-light-responsive structural color material and has great potential in display devices, anticounterfeiting labels, and data storage.

9.
Chemosphere ; 238: 124655, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31472344

RESUMO

The effectiveness of nitrate-mediated souring control highly depends on the interactions of sulfate reducing bacteria (SRB) and nitrate reducing bacteria (NRB). Biosurfactants produced by natural NRB are promising bio-agents for enhancing NRB competence towards SRB. However, the function of NRB-produced biosurfactants in NRB-SRB interactions remains unexplored due to the rarely successful isolation of natural biosurfactant-producing NRB. Hereby, biosurfactant-aided inhibitory control of SRB strain Desulfomicrobium escambiense ATCC 51164 by biosurfactant-producing NRB strain Pseudomonas stutzeri CX3, reported in our previous work, was investigated. Under non-sour conditions, insufficient nitrate injection resulted in limited SRB inhibition. Phospholipid fatty acid (PLFA) biomarkers traced the overall bacterial responses. Compositional PLFA patterns revealed biosurfactant addition benefitted both SRB and NRB towards stressful conditions. Under sour conditions, nitrite oxidation of sulfide proved to be the primary mechanism for sulfide removal. The subsequent elevation of redox potential and pH inhibited SRB activities. NRB-produced biosurfactants significantly enhanced SRB inhibition by NRB through more efficient sulfide removal and effective duration of nitrate in the microcosms. Biosurfactants specially produced by the NRB strain are for the first time reported to significantly strengthen SRB inhibition by NRB via reduced nitrate usage and prolonged effective duration of nitrate, which has encouraging potential in nitrate-dependent souring control.


Assuntos
Bactérias/isolamento & purificação , Desulfovibrio/metabolismo , Nitratos/metabolismo , Sulfetos/isolamento & purificação , Tensoativos/metabolismo , Bactérias/metabolismo , Ácidos Graxos/análise , Oxirredução
10.
Adv Mar Biol ; 81: 129-165, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30471655

RESUMO

In this study, the hexachlorobenzene molecule was modified by three-dimensional quantitative structure-activity relationship (3D-QSAR) models and a full factor experimental design to obtain new hexachlorobenzene molecules with low migration ability. The 3D-QSAR models (comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA)) were constructed by SYBLY-X 2.0 software, using experimental data of octanol-air partition coefficients (KOA) for 12 chlorobenzenes (CBs) congeners as the dependent variable, and the structural parameters of CBs as independent variables, respectively. A target molecule (hexachlorobenzene; HCB: its long-distance migration capability leads to pollution of the marine environment in Antarctic and Arctic) was modified using the 3D-QSAR contour maps associated with resolution V of the 210-3 full-factorial experimental design method, and 11 modified HCB molecules were produced with a single chlorine atom (-Cl2) and three chlorine atoms (-Cl1, -Cl3, and -Cl5) replaced with electropositive groups (-COOH, -CN, -CF3, -COF, -NO2, -F, -CHF2, -ONO2, and -SiF3) to increase the logKOA. The new molecules had essentially similar biological enrichment functions and toxicities as HCB but were found to be more easily degraded. A 2D-QSAR model and molecular docking technology indicated that both dipole moments and highest occupied orbital energies of the substituents markedly affected migration and degradation of the new molecules. The abilities of the compounds to undergo long distance migration were assessed. The modified HCB molecules (i.e. 2-CN-HCB, 2-CF3-HCB, 1-F-3-COOH-5-NO2-HCB, 1-NO2-3-CN-5-CHF2-HCB and 1-CN-3-F-5-NO2-HCB) moved from a long-range transport potential of the modified molecules to a relatively low mobility class, and the transport potentials of the remaining modified HCB molecules (i.e. 2-COOH-HCB, 2-COF-HCB, 1-COF-3-ONO2-5-NO2-HCB, 1-F-3-CN-5-SiF3-HCB, 1-F-3-COOH-5-SiF3-HCB and 1-CN-3-SiF3-5-ONO2-HCB) also significantly decreased. These results provide a basic theoretical basis for designing environmentally benign molecules based on HCB.


Assuntos
Hexaclorobenzeno/química , Poluentes Químicos da Água/química , Hidrologia , Simulação de Acoplamento Molecular , Estrutura Molecular , Relação Quantitativa Estrutura-Atividade , Projetos de Pesquisa
11.
Angew Chem Int Ed Engl ; 57(50): 16426-16430, 2018 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-30345597

RESUMO

Wavelength-controlled dynamic processes are mostly based on light-triggered isomerization or the cleavage/formation of molecular connections. Control over dynamic metathesis reactions by different light wavelengths, which would be useful in controllable dynamic chemistry, has rarely been studied. Taking advantage of the different bond energies of disulfide and diselenide bonds, we have developed a wavelength-driven exchange reaction between disulfides and diselenides, which underwent metathesis under UV light to produce Se-S bonds. When irradiated with visible light, the Se-S bonds were reversed back to those of the original reactants. The conversion of the exchange depends on the wavelength of the incident light. This light-driven metathesis chemistry was also applied to tune the mechanical properties of polymer materials. The visible-light-induced reverse reaction was compatible with reductant-catalyzed disulfide/diselenide metathesis, and could be utilized to develop a dissipative system with light as the energy input.

12.
Braz. j. microbiol ; 49(2): 258-268, Apr.-June 2018. graf
Artigo em Inglês | LILACS | ID: biblio-889233

RESUMO

Abstract Cellulosimicrobium cellulans CWS2, a novel strain capable of utilizing benzo(a)pyrene (BaP) as the sole carbon and energy source under nitrate-reducing conditions, was isolated from PAH-contaminated soil. Temperature and pH significantly affected BaP biodegradation, and the strain exhibited enhanced biodegradation ability at temperatures above 30 °C and between pH 7 and 10. The highest BaP removal rate (78.8%) was observed in 13 days when the initial BaP concentration was 10 mg/L, and the strain degraded BaP at constant rate even at a higher concentration (50 mg/L). Metal exposure experimental results illustrated that Cd(II) was the only metal ion that significantly inhibited biodegradation of BaP. The addition of 0.5 and 1.0 g/L glucose enhanced BaP biodegradation, while the addition of low-molecular-weight organic acids with stronger acidity reduced BaP removal rates during co-metabolic biodegradation. The addition of phenanthrene and pyrene, which were degraded to some extent by the strain, showed no distinct effect on BaP biodegradation. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that the five rings of BaP opened, producing compounds with one to four rings which were more bioavailable. Thus, the strain exhibited strong BaP degradation capability and has great potential in the remediation of BaP-/PAH-contaminated environments.


Assuntos
Microbiologia do Solo , Poluentes do Solo/metabolismo , Benzo(a)pireno/metabolismo , Actinobacteria/isolamento & purificação , Actinobacteria/metabolismo , Temperatura , Cádmio/metabolismo , Carbono/metabolismo , Ácidos Carboxílicos/metabolismo , Biotransformação , Actinobacteria/classificação , Meios de Cultura/química , Inibidores Enzimáticos/metabolismo , Glucose/metabolismo , Concentração de Íons de Hidrogênio , Anaerobiose , Cromatografia Gasosa-Espectrometria de Massas
13.
Bioprocess Biosyst Eng ; 41(6): 871-883, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29546466

RESUMO

In-depth understanding of indigenous microbial assemblages resulted from aged contamination by polycyclic aromatic hydrocarbons (PAHs) is of vital importance in successful in situ bioremediation treatments. Soil samples of three boreholes were collected at 12 different vertical depths. Overall, the dominating three-ring PAHs (76.2%) were closely related to distribution patterns of soil dehydrogenase activity, microbial cell numbers, and Shannon biodiversity index (H') of indigenous microorganisms. High-molecular-weight PAHs tend to yield more diverse communities. Results from 16S rRNA analysis indicated that possible functional groups of PAH degradation include three species in Bacillus cereus group, Bacillus sp. SA Ant14, Nocardioides sp., and Ralstonia pickettii. Principal component analysis indicates significant positive correlations between the content of high-molecular-weight PAHs and the distribution of Bacillus weihenstephanensis KBAB4 and Nocardioides sp. The species B. cereus 03BB102, Bacillus thuringiensis, B. weihenstephanensis KBAB4, and Nocardioides sp. were recognized as main PAH degraders and thus recommended to be utilized in further bioremediation applications. The vertical distribution characteristics of PAHs in soil profiles (1-12 m) and the internal relationship between the transport mechanisms of PAHs and the response of soil biological properties help further understand the microbial diversity and activity in an aged site.


Assuntos
Bactérias , Biodiversidade , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Solo , Bactérias/classificação , Bactérias/metabolismo
14.
Braz J Microbiol ; 49(2): 258-268, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29102294

RESUMO

Cellulosimicrobium cellulans CWS2, a novel strain capable of utilizing benzo(a)pyrene (BaP) as the sole carbon and energy source under nitrate-reducing conditions, was isolated from PAH-contaminated soil. Temperature and pH significantly affected BaP biodegradation, and the strain exhibited enhanced biodegradation ability at temperatures above 30°C and between pH 7 and 10. The highest BaP removal rate (78.8%) was observed in 13 days when the initial BaP concentration was 10mg/L, and the strain degraded BaP at constant rate even at a higher concentration (50mg/L). Metal exposure experimental results illustrated that Cd(II) was the only metal ion that significantly inhibited biodegradation of BaP. The addition of 0.5 and 1.0g/L glucose enhanced BaP biodegradation, while the addition of low-molecular-weight organic acids with stronger acidity reduced BaP removal rates during co-metabolic biodegradation. The addition of phenanthrene and pyrene, which were degraded to some extent by the strain, showed no distinct effect on BaP biodegradation. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that the five rings of BaP opened, producing compounds with one to four rings which were more bioavailable. Thus, the strain exhibited strong BaP degradation capability and has great potential in the remediation of BaP-/PAH-contaminated environments.


Assuntos
Actinobacteria/isolamento & purificação , Actinobacteria/metabolismo , Benzo(a)pireno/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Actinobacteria/classificação , Anaerobiose , Biotransformação , Cádmio/metabolismo , Carbono/metabolismo , Ácidos Carboxílicos/metabolismo , Meios de Cultura/química , Inibidores Enzimáticos/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Glucose/metabolismo , Concentração de Íons de Hidrogênio , Temperatura
15.
Bioprocess Biosyst Eng ; 40(12): 1825-1838, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28913631

RESUMO

High-molecular-weight polycyclic aromatic hydrocarbons are persistent organic pollutants with great environmental and human health risks and the associated bioremediation activities have always been hampered by the lack of powerful bacterial species under redox conditions. A Microbacterium sp. strain capable of using benzo(a)pyrene as sole carbon and energy sources under denitrifying conditions was isolated. The difference in protein expression during BaP removal and removal characterization were investigated. A total of 146 proteins were differentially expressed, 44 proteins were significantly up-regulated and 102 proteins were markedly down-regulated. GO and COG analysis showed that BaP removal inhibited the expression of proteins related to glucose metabolism at different levels and activated other metabolic pathway. The proteins associated with catalytic activity and metabolic process were altered significantly. Furthermore, the BaP removal might be occurred in certain organelle of M.CSW3. The strain removed BaP with a speed of 0.0657-1.0072 mg/L/day over the concentrations range 2.5-100 mg/L. High removal rates (>70%) were obtained over the range of pH 7-11 in 14 days. Carbohydrates and organic acids which could be utilized by the strain, as well as heavy metal ions, reduced BaP removal efficiency. However, phenanthrene or pyrene addition enhanced the removal capability of M.CSW3. The strain was proved to have practical potential for bioremediation of PAHs-contaminated soil and this study provided a powerful platform for further application by improving production of associated proteins.


Assuntos
Actinobacteria/metabolismo , Proteínas de Bactérias/metabolismo , Benzo(a)pireno/isolamento & purificação , Proteômica , Actinobacteria/genética , Carbono/metabolismo , Catálise , Desnitrificação , Regulação para Baixo , Glucose/metabolismo , Filogenia , RNA Ribossômico 16S/genética
16.
ACS Appl Mater Interfaces ; 9(38): 33169-33175, 2017 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-28882033

RESUMO

Plasticity of thermoset polymers has been realized by introducing exchangeable bonds, and the plasticity is mostly triggered via heat or UV light. Visible light is a relatively mild trigger that has not been used to induce plasticity in polymer materials. Herein, thermoset polyurethanes (PUs) containing diselenide bonds are fabricated that possess visible light-induced plasticity along with shape memory behavior. A series of PUs with different diselenide bond contents were tested and their shape memory properties and plasticity varied. With a higher diselenide bond content, both shape memory and light-induced plasticity are achieved. By combining these two properties, reshaping the permanent shapes of the PUs is easier. Compared with heat or UV light, visible light has the advantage of spatial control. For instance, a pattern of visible light was introduced by a commercial projector to demonstrate facile reshaping of the materials. Because visible light can be introduced via various methods, PUs with visible light-induced plasticity have great potential applications.

17.
Mar Pollut Bull ; 122(1-2): 194-206, 2017 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-28655458

RESUMO

A method based on phospholipid fatty acid (PLFA) analysis for profiling microbial communities in offshore produced water was optimized. The operation parameters affecting final PLFA profiling performance from the solid phase extraction (SPE) purification and fatty acid methyl esters (FAMEs) yielding process were investigated. Under the selected conditions, 92.9%, 96.3% and 92.8% of the spiked phospholipid standards C16:1 (cis-9) PC, C18:1 (cis-9) PC, and C19:0 PC were recovered, respectively, using 10mL methanol as elution solvent on a non-commercial SPE column. Over 90% of spiked C19:0 PC was recovered before sample transesterification. Four parameters including alkaline reagent, volume of acid for neutralization, time and temperature for FAMEs derivatization were examined. Gas Chromatography-Mass Spectrometry (GC-MS) was used to analyze FAMEs and the method linearities, recoveries of 29 FAMEs during transesterification, detection limits, relative standard deviations were presented. The results provided valuable information for biological reservoir souring control.


Assuntos
Monitoramento Ambiental/métodos , Ácidos Graxos/análise , Microbiologia da Água , Cromatografia Gasosa-Espectrometria de Massas , Extração em Fase Sólida , Água , Poluentes Químicos da Água
18.
Bioresour Technol ; 232: 263-269, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28236759

RESUMO

Rhodococcus erythropolis M-25, one of the representative biosurfactant producers, performed effectively during the biodegradation of four crude oil. The microbial degradation efficiency is positively relevant to the API of the crude oil. The chemical dispersant Corexit 9500A did not enhance the biodegradation of the petroleum hydrocarbons during the experimental period. 70.7% of the N-4 oil was degraded after 30days, while in the Corexit 9500A plus sample the biodegradation removal was 42.8%. The Corexit-derived compounds were metabolized by M-25 at the same time of the petroleum hydrocarbons biodegrading. Neither biodegradation nor chemical dispersion process has almost no effect on the biomarker (m/z=231). The saturated methyl-branched fatty acids increased from 37.3%, to 49.4%, when M-25 was exposed with the N-4 crude oil. Similarly, the saturated methyl-branched fatty acids in the membrane of N3-2P increased from 20.25% to 44.1%, when exposed it with the N-4 crude oil.


Assuntos
Biodegradação Ambiental , Poluição por Petróleo , Petróleo/metabolismo , Rhodococcus/metabolismo , Tensoativos/metabolismo , Hidrocarbonetos/metabolismo , Lipídeos/química
19.
ACS Appl Mater Interfaces ; 8(26): 17004-10, 2016 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-27301845

RESUMO

Tellurium-containing photoresponsive polyelectrolyte multilayer films were fabricated by layer-by-layer assembly of a tellurium-containing polymer, photosensitizer, and poly(styrenesulfonate). The resulting films were investigated by UV/vis spectroscopy, XPS, EPR, and fluorescence spectroscopy. Under visible light, the photosensitizer in the film is excited and transforms triplet oxygen into singlet oxygen in aqueous solution. Singlet oxygen oxidizes -Te- to high valence state (Te═O) on the polymer backbone. The generated (Te═O) group makes the micelles more hydrophilic and looser, thereby facilitating the controlled release of the loaded cargo of micelles. These results show that the film has the potential to be used for cargo loading and controlled release, thus may provide a new way to combine photodynamic therapy and chemotherapy.


Assuntos
Fotoquimioterapia/métodos , Polímeros/química , Telúrio/química , Fármacos Fotossensibilizantes/química
20.
ACS Appl Mater Interfaces ; 7(29): 16054-60, 2015 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-26154159

RESUMO

Reactive oxygen species (ROS) play crucial roles in cell signaling and redox homeostasis and are strongly related to metabolic activities. The increase of the ROS concentration in organisms can result in several diseases, such as cardiovascular diseases and cancer. The concentration of ROS in biologically relevant conditions is typically as low as around tens of micromolars to 100 µM H2O2, which makes it necessary to develop ultrasensitive ROS-responsive systems. A general approach is reported here to fabricate an ultrasensitive ROS-responsive system via coassembly between tellurium-containing molecules and phospholipids, combining the ROS-responsiveness of tellurium and the biocompatibility of phospholipids. By using dynamic light scattering, transmission electron microscopy, scanning electron microscopy, and NMR spectra, coassembly behaviors and the responsiveness of the coassemblies have been investigated. These coassemblies can respond to 100 µM H2O2, which is a biologically relevant ROS concentration, and demonstrate reversible redox properties.


Assuntos
Técnicas de Sonda Molecular , Sondas Moleculares/síntese química , Fosfolipídeos/química , Espécies Reativas de Oxigênio/análise , Espécies Reativas de Oxigênio/química , Telúrio/química , Teste de Materiais , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
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