Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 6.688
Filtrar
1.
Commun Biol ; 7(1): 725, 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38867087

RESUMO

The rising use of plastic results in an appalling amount of waste which is scattered into the environment. One of these plastics is PET which is mainly used for bottles. We have identified and characterized an esterase from Streptomyces, annotated as LipA, which can efficiently degrade the PET-derived oligomer BHET. The Streptomyces coelicolor ScLipA enzyme exhibits varying sequence similarity to several BHETase/PETase enzymes, including IsPETase, TfCut2, LCC, PET40 and PET46. Of 96 Streptomyces strains, 18% were able to degrade BHET via one of three variants of LipA, named ScLipA, S2LipA and S92LipA. SclipA was deleted from S. coelicolor resulting in reduced BHET degradation. Overexpression of all LipA variants significantly enhanced BHET degradation. All variants were expressed in E. coli for purification and biochemical analysis. The optimum conditions were determined as pH 7 and 25 °C for all variants. The activity on BHET and amorphous PET film was investigated. S2LipA efficiently degraded BHET and caused roughening and indents on the surface of PET films, comparable to the activity of previously described TfCut2 under the same conditions. The abundance of the S2LipA variant in Streptomyces suggests an environmental advantage towards the degradation of more polar substrates including these polluting plastics.


Assuntos
Streptomyces , Streptomyces/enzimologia , Streptomyces/genética , Microbiologia do Solo , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/química , Biodegradação Ambiental , Streptomyces coelicolor/enzimologia , Streptomyces coelicolor/genética , Esterases/metabolismo , Esterases/genética , Esterases/química , Polietilenotereftalatos/metabolismo
2.
J Environ Manage ; 363: 121360, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38850902

RESUMO

Large-volume production of poly(ethylene terephthalate) (PET), especially in the form of bottles and food packaging containers, causes problems with polymer waste management. Waste PET could be recycled thermally, mechanically or chemically and the last method allows to obtain individual monomers, but most often it is carried out in the presence of homogeneous catalysts, that are difficult to separate and reuse. In view of this, this work reports for the first time, application of bimetallic MOF-74 - as heterogeneous catalyst - for depolymerization of PET with high monomer (bishydroxyethyl terephthalate, BHET) recovery. The effect of type and amount of second metal in the MOF-74 (Mg/M) was systematically investigated. The results showed increased activity of MOF-74 (Mg/M) containing Co2+, Zn2+ and Mn2+ as a second metal, while the opposite correlation was observed for Cu2+ and Ni2+. It was found that the highest catalytic activity was demonstrated by the introduction of Mg-Mn into MOF-74 with ratio molar 1:1, which resulted in complete depolymerization of PET and 91.8% BHET yield within 4 h. Furthermore, the obtained catalyst showed good stability in 5 reaction cycles and allowed to achieve high-purity BHET, which was confirmed by HPLC analysis. The as-prepared MOF-74 (Mg/Mn) was easy to separate from the post-reaction mixture, clean and reuse in the next depolymerization reaction.


Assuntos
Polietilenotereftalatos , Catálise , Polietilenotereftalatos/química , Polimerização , Gerenciamento de Resíduos/métodos , Reciclagem , Estruturas Metalorgânicas/química
3.
World J Microbiol Biotechnol ; 40(8): 247, 2024 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-38904858

RESUMO

Phthalate isomers are key intermediates in the biodegradation of pollutants including waste polyethylene terephthalate (PET) plastics and plasticizers. So far, an increasing number of phthalate isomer-degrading strains have been isolated, and their degradation pathways show significant diversity. In this paper, we comprehensively review the current status of research on the degrading bacteria, degradation characteristics, aerobic and anaerobic degradation pathways, and degradation genes (clusters) of phthalate isomers, and discuss the current shortcomings and challenges. Moreover, the degradation process of phthalate isomers produces many important aromatic precursor molecules, which can be used to produce higher-value derivative chemicals, and the modification of their degradation pathways holds good prospects. Therefore, this review also highlights the current progress made in modifying the phthalate isomer degradation pathway and explores its potential for high-value applications.


Assuntos
Bactérias , Biodegradação Ambiental , Ácidos Ftálicos , Ácidos Ftálicos/metabolismo , Bactérias/metabolismo , Bactérias/genética , Bactérias/classificação , Isomerismo , Plastificantes/metabolismo , Poluentes Ambientais/metabolismo , Redes e Vias Metabólicas , Polietilenotereftalatos/metabolismo , Polietilenotereftalatos/química
4.
Dental Press J Orthod ; 29(2): e2423212, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38865514

RESUMO

OBJECTIVE: The purpose of this retrospective study was to compare accuracy of arch expansion using two different thermoplastic materials in Invisalign aligners: EX30® (Polyethylene Terephthalate Glycol, or PETG) and SmartTrack® (polyurethane). METHODS: The study sample comprised 65 adult patients consecutively treated with Invisalign from two private practices: group 1 - treated with EX30® (358 teeth) and group 2 - treated with SmartTrack® (888 teeth). Six hundred and twenty-three measurements were assessed in three digital models throughout treatment: model 1 - initial, model 2 - predicted tooth position, and model 3 - achieved position. Sixteen reference points per arch were marked and, after best alignment, 2 points per tooth were copied from one digital model to another. Linear values of both arches were measured for canines, premolars, and first molars: on lingual gingival margins and cusp tips of every tooth. Comparisons were performed by Wilcoxon and Mann-Whitney test. RESULTS: Both termoplastic materials presented significant differences between predicted and achieved values for all measurements, except for the lower molar cusp tip in the SmartTrack® group. There is no statistical difference in the accuracy of transverse expansion between these two materials. Overall accuracy for EX30® aligners in maxilla and mandible were found to be 37 and 38%, respectively; and Smarttrack® presented an overall accuracy of 56.62% in the maxilla and 68.72% in the mandible. CONCLUSIONS: It is not possible to affirm one material expands better than the other. Further controlled clinical studies should be conducted comparing SmartTrack® and EX30® under similar conditions.


Assuntos
Desenho de Aparelho Ortodôntico , Polietilenotereftalatos , Poliuretanos , Técnicas de Movimentação Dentária , Humanos , Estudos Retrospectivos , Adulto , Feminino , Técnicas de Movimentação Dentária/instrumentação , Masculino , Poliuretanos/uso terapêutico , Polietilenoglicóis , Arco Dental , Aparelhos Ortodônticos Removíveis , Adulto Jovem
5.
J Environ Manage ; 361: 121258, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38815428

RESUMO

The rising accumulation of poly(ethylene terephthalate) (PET) waste presents an urgent ecological challenge, necessitating an efficient and economical treatment technology. Here, we developed chemical-biological module clusters that perform chemical pretreatment, enzymatic degradation, and microbial assimilation for the large-scale treatment of PET waste. This module cluster included (i) a chemical pretreatment that involves incorporating polycaprolactone (PCL) at a weight ratio of 2% (PET:PCL = 98:2) into PET via mechanical blending, which effectively reduces the crystallinity and enhances degradation; (ii) enzymatic degradation using Thermobifida fusca cutinase variant (4Mz), that achieves complete degradation of pretreated PET at 300 g/L PET, with an enzymatic loading of 1 mg protein per gram of PET; and (iii) microbial assimilation, where Rhodococcus jostii RHA1 metabolizes the degradation products, assimilating each monomer at a rate above 90%. A comparative life cycle assessment demonstrated that the carbon emissions from our module clusters (0.25 kg CO2-eq/kg PET) are lower than those from other established approaches. This study pioneers a closed-loop system that seamlessly incorporates pretreatment, degradation, and assimilation processes, thus mitigating the environmental impacts of PET waste and propelling the development of a circular PET economy.


Assuntos
Biodegradação Ambiental , Poliésteres , Polietilenotereftalatos , Polietilenotereftalatos/química , Polietilenotereftalatos/metabolismo , Poliésteres/metabolismo , Poliésteres/química , Hidrolases de Éster Carboxílico
6.
Environ Res ; 255: 119144, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-38751006

RESUMO

Currently, plastic waste and antibiotic wastewater are two of the most critical environmental problems, calling for urgent measures to take. A waste-to-wealth strategy for the conversion of polyethylene terephthalate (PET) plastic bottles into value-added materials such as carbon composite is highly recommended to clean wastewater contaminated by antibiotics. Inspired by this idea, we develop a novel PET-AC-ZFO composite by incorporating PET plastic-derived KOH-activated carbon (AC) with ZnFe2O4 (ZFO) particles for adsorptive removal of tetracycline (TTC). PET-derived carbon (PET-C), KOH-activated PET-derived carbon (PET-AC), and PET-AC-ZFO were characterized using physicochemical analyses. Central composite design (CCD) was used to obtain a quadratic model by TTC concentration (K), adsorbent dosage (L), and pH (M). PET-AC-ZFO possessed micropores (d ≈ 2 nm) and exceptionally high surface area of 1110 m2 g-1. Nearly 90% TTC could be removed by PET-AC-ZFO composite. Bangham kinetic and Langmuir isotherm were two most fitted models. Theoretical maximum TTC adsorption capacity was 45.1 mg g-1. This study suggested the role of hydrogen bonds, pore-filling interactions, and π-π interactions as the main interactions of the adsorption process. Thus, a strategy for conversion of PET bottles into PET-AC-ZFO can contribute to both plastic recycling and antibiotic wastewater mitigation.


Assuntos
Antibacterianos , Carbono , Tetraciclina , Poluentes Químicos da Água , Adsorção , Poluentes Químicos da Água/química , Poluentes Químicos da Água/análise , Tetraciclina/química , Antibacterianos/química , Carbono/química , Plásticos/química , Purificação da Água/métodos , Águas Residuárias/química , Polietilenotereftalatos/química
7.
J Chem Inf Model ; 64(10): 4112-4120, 2024 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-38703106

RESUMO

Understanding the mechanisms influencing poly(ethylene terephthalate) (PET) biodegradation is crucial for developing innovative strategies to accelerate the breakdown of this persistent plastic. In this study, we employed all-atom molecular dynamics simulation to investigate the adsorption process of the LCC-ICCG cutinase enzyme onto the PET surface. Our results revealed that hydrophobic, π-π, and H bond interactions, specifically involving aliphatic, aromatic, and polar uncharged amino acids, were the primary driving forces for the adsorption of the cutinase enzyme onto PET. Additionally, we observed a negligible change in the enzyme's tertiary structure during the interaction with PET (RMSD = 1.35 Å), while its secondary structures remained remarkably stable. Quantitative analysis further demonstrated that there is about a 24% decrease in the number of enzyme-water hydrogen bonds upon adsorption onto the PET surface. The significance of this study lies in unraveling the molecular intricacies of the adsorption process, providing valuable insights into the initial steps of enzymatic PET degradation.


Assuntos
Hidrolases de Éster Carboxílico , Estabilidade Enzimática , Simulação de Dinâmica Molecular , Polietilenotereftalatos , Polietilenotereftalatos/química , Polietilenotereftalatos/metabolismo , Adsorção , Hidrolases de Éster Carboxílico/química , Hidrolases de Éster Carboxílico/metabolismo , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas
8.
J Hazard Mater ; 472: 134480, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38703683

RESUMO

The widespread use of polyethylene terephthalate (PET) in various industries has led to a surge in microplastics (MPs) pollution, posing a significant threat to ecosystems and human health. To address this, we have developed a bacterial enzyme cascade reaction system (BECRS) that focuses on the efficient degradation of PET. This system harnesses the Escherichia coli (E. coli) surface to display CsgA protein, which forms curli fibers, along with the carbohydrate-binding module 3 (CBM3) and PETases, to enhance the adsorption and degradation of PET. The study demonstrated that the BECRS achieved a notable PET film degradation rate of 3437 ± 148 µg/(d*cm²), with a degradation efficiency of 21.40% for crystalline PET MPs, and the degradation products were all converted to TPA. The stability of the system was evidenced by retaining over 80% of its original activity after multiple uses and during one month of storage. Molecular dynamics simulations confirmed that the presence of CsgA did not interfere with the enzymatic activity of PETases. This BECRS represents a significant step forward in the biodegradation of PET, particularly microplastics, offering a practical and sustainable solution for environmental pollution control.


Assuntos
Biodegradação Ambiental , Escherichia coli , Polietilenotereftalatos , Polietilenotereftalatos/metabolismo , Polietilenotereftalatos/química , Escherichia coli/metabolismo , Microplásticos/metabolismo , Microplásticos/química , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/química , Simulação de Dinâmica Molecular , Proteínas de Escherichia coli/metabolismo , Adsorção
9.
J Hazard Mater ; 472: 134448, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38728862

RESUMO

Microplastics (MPs) are a major concern in marine ecosystem because MPs are persistent and ubiquitous in oceans and are easily consumed by marine biota. Although many studies have reported the toxicity of MPs to marine biota, the toxicity of environmentally relevant types of MPs is little understood. We investigated the toxic effects of fragmented polyethylene terephthalate (PET) MP, one of the most abundant MPs in the ocean, on the marine rotifer Brachionus koreanus at the individual and molecular level. No significant rotifer mortality was observed after exposure to PET MPs for 24 and 48 h. The ingestion and egestion assays showed that rotifers readily ingested PET MPs in the absence of food but not when food was supplied; thus, there were also no chronic effects of PET MPs. In contrast, intracellular reactive oxygen species levels and glutathione S-transferase activity in rotifers were significantly increased by PET MPs. Transcriptomic and metabolomic analyses revealed that genes and metabolites related to energy metabolism and immune processes were significantly affected by PET MPs in a concentration-dependent manner. Although acute toxicity of PET MPs was not observed, PET MPs are potentially toxic to the antioxidant system, immune system, and energy metabolism in rotifers.


Assuntos
Microplásticos , Polietilenotereftalatos , Espécies Reativas de Oxigênio , Rotíferos , Poluentes Químicos da Água , Animais , Rotíferos/efeitos dos fármacos , Polietilenotereftalatos/toxicidade , Microplásticos/toxicidade , Poluentes Químicos da Água/toxicidade , Espécies Reativas de Oxigênio/metabolismo , Glutationa Transferase/metabolismo , Glutationa Transferase/genética , Testes de Toxicidade , Transcriptoma/efeitos dos fármacos , Metabolômica , Ingestão de Alimentos , Multiômica
10.
Sci Total Environ ; 933: 173048, 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-38740204

RESUMO

Microplastics (MPs) are ubiquitous in freshwater sediments, raising concern about their potential impacts on ecosystem services. However, the specific impacts of microbiota mediated by MPs in sediment and plastisphere compartments on P availability remain elusive. This investigation conducted a series of microcosm experiments utilizing eutrophic lake sediment amended with fuel-based polyethylene terephthalate (PET), bio-based polylactic acid (PLA) MPs, and a natural cobblestone substrate to unravel their effects. The findings highlighted that MPs induced alterations in bacterial communities in both sediment and plastisphere, consequently modifying P availabilities at the sediment-water interface (SWI). In comparison to non-biodegradable PET, biodegradable PLA MPs presented higher proportions of specific bacteria and functional genes associated with P profiles, such as Firmicutes, Ignavibacteriota, and P mineralizing genes in the sediment and plastisphere. This, in turn, elevated the levels of soluble reactive P in the porewater by 54.19 % (0-1 cm), 55.81 % (1-3 cm), and 18.24 % (3-5 cm), respectively. Additionally, PLA obviously altered P immobilization capacity and bioavailability, increasing the organic P fraction. Whereas, inert cobblestone exhibited negligible influence on P biogeochemical processes during the incubation. Moreover, the biofilm communities and those in the surrounding sediment specifically contributed to the changes in P profiles at the SWI. The functional genes associated with P profiles in the sediment mainly concentrate on P mineralization and P uptake/transport. In the plastisphere, P activation genes are obviously affected under MP exposure. This study fills the knowledge gap concerning the repercussions of MPs on ecosystem services.


Assuntos
Sedimentos Geológicos , Microbiota , Microplásticos , Fósforo , Poluentes Químicos da Água , Sedimentos Geológicos/microbiologia , Sedimentos Geológicos/química , Microbiota/efeitos dos fármacos , Fósforo/análise , Poluentes Químicos da Água/análise , Poliésteres , Bactérias , Lagos/microbiologia , Lagos/química , Polietilenotereftalatos , Ecossistema
11.
Protein Sci ; 33(6): e4997, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38723110

RESUMO

Rieske oxygenases (ROs) are a diverse metalloenzyme class with growing potential in bioconversion and synthetic applications. We postulated that ROs are nonetheless underutilized because they are unstable. Terephthalate dioxygenase (TPADO PDB ID 7Q05) is a structurally characterized heterohexameric α3ß3 RO that, with its cognate reductase (TPARED), catalyzes the first intracellular step of bacterial polyethylene terephthalate plastic bioconversion. Here, we showed that the heterologously expressed TPADO/TPARED system exhibits only ~300 total turnovers at its optimal pH and temperature. We investigated the thermal stability of the system and the unfolding pathway of TPADO through a combination of biochemical and biophysical approaches. The system's activity is thermally limited by a melting temperature (Tm) of 39.9°C for the monomeric TPARED, while the independent Tm of TPADO is 50.8°C. Differential scanning calorimetry revealed a two-step thermal decomposition pathway for TPADO with Tm values of 47.6 and 58.0°C (ΔH = 210 and 509 kcal mol-1, respectively) for each step. Temperature-dependent small-angle x-ray scattering and dynamic light scattering both detected heat-induced dissociation of TPADO subunits at 53.8°C, followed by higher-temperature loss of tertiary structure that coincided with protein aggregation. The computed enthalpies of dissociation for the monomer interfaces were most congruent with a decomposition pathway initiated by ß-ß interface dissociation, a pattern predicted to be widespread in ROs. As a strategy for enhancing TPADO stability, we propose prioritizing the re-engineering of the ß subunit interfaces, with subsequent targeted improvements of the subunits.


Assuntos
Estabilidade Enzimática , Oxirredutases/química , Oxirredutases/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Modelos Moleculares , Dioxigenases/química , Dioxigenases/metabolismo , Dioxigenases/genética , Temperatura , Escherichia coli/enzimologia , Escherichia coli/genética , Escherichia coli/metabolismo , Polietilenotereftalatos/química , Polietilenotereftalatos/metabolismo , Concentração de Íons de Hidrogênio , Complexo III da Cadeia de Transporte de Elétrons
12.
Part Fibre Toxicol ; 21(1): 26, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38778339

RESUMO

BACKGROUND: During inhalation, airborne particles such as particulate matter ≤ 2.5 µm (PM2.5), can deposit and accumulate on the alveolar epithelial tissue. In vivo studies have shown that fractions of PM2.5 can cross the alveolar epithelium to blood circulation, reaching secondary organs beyond the lungs. However, approaches to quantify the translocation of particles across the alveolar epithelium in vivo and in vitro are still not well established. In this study, methods to assess the translocation of standard diesel exhaust particles (DEPs) across permeable polyethylene terephthalate (PET) inserts at 0.4, 1, and 3 µm pore sizes were first optimized with transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-VIS), and lock-in thermography (LIT), which were then applied to study the translocation of DEPs across human alveolar epithelial type II (A549) cells. A549 cells that grew on the membrane (pore size: 3 µm) in inserts were exposed to DEPs at different concentrations from 0 to 80 µg.mL- 1 ( 0 to 44 µg.cm- 2) for 24 h. After exposure, the basal fraction was collected and then analyzed by combining qualitative (TEM) and quantitative (UV-VIS and LIT) techniques to assess the translocated fraction of the DEPs across the alveolar epithelium in vitro. RESULTS: We could detect the translocated fraction of DEPs across the PET membranes with 3 µm pore sizes and without cells by TEM analysis, and determine the percentage of translocation at approximatively 37% by UV-VIS (LOD: 1.92 µg.mL- 1) and 75% by LIT (LOD: 0.20 µg.cm- 2). In the presence of cells, the percentage of DEPs translocation across the alveolar tissue was determined around 1% at 20 and 40 µg.mL- 1 (11 and 22 µg.cm- 2), and no particles were detected at higher and lower concentrations. Interestingly, simultaneous exposure of A549 cells to DEPs and EDTA can increase the translocation of DEPs in the basal fraction. CONCLUSION: We propose a combination of analytical techniques to assess the translocation of DEPs across lung tissues. Our results reveal a low percentage of translocation of DEPs across alveolar epithelial tissue in vitro and they correspond to in vivo findings. The combination approach can be applied to any traffic-generated particles, thus enabling us to understand their involvement in public health.


Assuntos
Material Particulado , Alvéolos Pulmonares , Emissões de Veículos , Humanos , Emissões de Veículos/toxicidade , Emissões de Veículos/análise , Células A549 , Material Particulado/toxicidade , Material Particulado/análise , Alvéolos Pulmonares/efeitos dos fármacos , Alvéolos Pulmonares/metabolismo , Tamanho da Partícula , Microscopia Eletrônica de Transmissão , Polietilenotereftalatos/química , Polietilenotereftalatos/toxicidade , Células Epiteliais Alveolares/efeitos dos fármacos , Células Epiteliais Alveolares/metabolismo , Poluentes Atmosféricos/toxicidade , Poluentes Atmosféricos/análise
13.
Waste Manag ; 183: 260-270, 2024 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-38776828

RESUMO

The landfill is one of the most important sources of microplastics (MPs). The pretreatment method is a precondition of microplastics study for the presence of complex substances in landfills. Therefore, it is essential to examine the impact of different pretreatment methods on the microplastics detection. A literature review and a comparison experiment on digestion solutions were performed to establish a comprehensive identification method for MPs in landfills. When exposed to of 30 % H2O2, minimal mass reduction of PE, PP and PET were 4.00 %, 3.00 % and 3.00 % respectively, and the least surface damage was observed in MPs, while exhibiting the most optimal peak value for infrared spectral characteristics. It is demonstrated that the effect of 30 % H2O2 dissolution was superior compared to 10 % KOH and 65 % HNO3. The method was subsequently utilized to investigate the distribution of MPs in a landfill. The dominant MPs were polyethylene (PE, 18.56-23.91 %), polyethylene terephthalate (PET, 8.80-18.66 %), polystyrene (PS, 10.31-18.09 %), and polypropylene (PP, 11.60-14.91 %). The comprehensive identification method of "NaCl density separation + 30 % H2O2 digestion + NaI density separation + sampling microscope + Mirco-FTIR" is suitable for the detection of MPs in landfills.


Assuntos
Resíduos Sólidos , Instalações de Eliminação de Resíduos , Eliminação de Resíduos/métodos , Polietileno/análise , Polietilenotereftalatos/análise , Poliestirenos/análise , Polipropilenos/análise
14.
Mar Pollut Bull ; 203: 116441, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38703629

RESUMO

Microplastics (MPs) in the aquatic environment pose a serious threat to biota, by being confounded with food. These effects occur in mussels which are filter-feeding organisms. Mussels from the genus Mytilus sp. were used to evaluate the ecotoxicological effects of two MPs, polypropylene (PP) and polyethylene terephthalate (PET), after 4 and 28-days. Measured individual endpoints were condition index and feeding rate; and sub-individual parameters, metabolism of phase I (CYP1A1, CYP1A2 and CYP3A4) and II (glutathione S-transferases - GSTs), and antioxidant defense (catalase - CAT). MPs decreased both condition index (CI) and feeding rate (FR). No alterations occurred in metabolic enzymes, suggesting that these MPs are not metabolized by these pathways. Furthermore, lack of alterations in GSTs and CAT activities suggests the absence of conjugation and oxidative stress. Overall, biochemical markers were not responsive, but non-enzymatic responses showed deleterious effects caused by these MPs, which may be of high ecological importance.


Assuntos
Ecotoxicologia , Microplásticos , Mytilus , Poluentes Químicos da Água , Animais , Poluentes Químicos da Água/toxicidade , Microplásticos/toxicidade , Mytilus/efeitos dos fármacos , Monitoramento Ambiental , Glutationa Transferase/metabolismo , Polipropilenos/toxicidade , Polietilenotereftalatos , Estresse Oxidativo , Catalase/metabolismo
15.
Environ Pollut ; 352: 124131, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38734049

RESUMO

Polyethylene terephthalate (PET) plastic pollution is widely found in deep-sea sediments. Despite being an international environmental issue, it remains unclear whether PET can be degraded through bioremediation in the deep sea. Pelagic sediments obtained from 19 sites across a wide geographic range in the Pacific Ocean were used to screen for bacteria with PET degrading potential. Bacterial consortia that could grow on PET as the sole carbon and energy source were found in 10 of the 19 sites. These bacterial consortia showed PET removal rate of 1.8%-16.2% within two months, which was further confirmed by the decrease of carbonyl and aliphatic hydrocarbon groups using attenuated total reflectance-Fourier-transform infrared analysis (ATR-FTIR). Analysis of microbial diversity revealed that Alcanivorax and Pseudomonas were predominant in all 10 PET degrading consortia. Meanwhile, Thalassospira, Nitratireductor, Nocardioides, Muricauda, and Owenweeksia were also found to possess PET degradation potential. Metabolomic analysis showed that Alcanivorax sp. A02-7 and Pseudomonas sp. A09-2 could turn PET into mono-(2-hydroxyethyl) terephthalate (MHET) even in situ stimulation (40 MPa, 10 °C) conditions. These findings widen the currently knowledge of deep-sea PET biodegrading process with bacteria isolates and degrading mechanisms, and indicating that the marine environment is a source of biotechnologically promising bacterial isolates and enzymes.


Assuntos
Bactérias , Biodegradação Ambiental , Sedimentos Geológicos , Polietilenotereftalatos , Poluentes Químicos da Água , Polietilenotereftalatos/metabolismo , Oceano Pacífico , Sedimentos Geológicos/microbiologia , Sedimentos Geológicos/química , Bactérias/metabolismo , Bactérias/isolamento & purificação , Poluentes Químicos da Água/metabolismo , Poluentes Químicos da Água/análise , Água do Mar/microbiologia , Pseudomonas/metabolismo
16.
Chemosphere ; 359: 142314, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38735489

RESUMO

Continuously growing adoption of electronic devices in energy storage, human health and environmental monitoring systems increases demand for cost-effective, lightweight, comfortable, and highly efficient functional structures. In this regard, the recycling and reuse of polyethylene terephthalate (PET) waste in the aforementioned fields due to its excellent mechanical properties and chemical resistance is an effective solution to reduce plastic waste. Herein, we review recent advances in synthesis procedures and research studies on the integration of PET into energy storage (Li-ion batteries) and the detection of gaseous and biological species. The operating principles of such systems are described and the role of recycled PET for various types of architectures is discussed. Modifying the composition, crystallinity, surface porosity, and polar surface functional groups of PET are important factors for tuning its features as the active or substrate material in biological and gas sensors. The findings indicate that conceptually new pathways to the study are opened up for the effective application of recycled PET in the design of Li-ion batteries, as well as biochemical and catalytic detection systems. The current challenges in these fields are also presented with perspectives on the opportunities that may enable a circular economy in PET use.


Assuntos
Técnicas Biossensoriais , Fontes de Energia Elétrica , Gases , Polietilenotereftalatos , Reciclagem , Polietilenotereftalatos/química , Técnicas Biossensoriais/métodos , Gases/análise , Monitoramento Ambiental/métodos
17.
Chemosphere ; 359: 142313, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38735499

RESUMO

Electrospinning is a promising technique for the beneficial use and recycling of plastic waste polymers using simple methodologies. In this study, plastic bottles and Styrofoam wastes have been used to develop polyethylene terephthalate (PET) and polystyrene (PS) nanofibers using electrospinning technique separately without any further purification. The effect of the concentration onto the nanofiber's morphology was studied. The fabricated nanofibers were characterized using Field Emission Scanning Electron Microscope (FE-SEM), Fourier Transformed Infrared Spectroscopy (ATR-FTIR), N2 adsorption/desorption analysis, and water contact angle (WCA). Furthermore, the prepared nanofibers were applied for the adsorption of ibuprofen (IBU) from wastewater. Some parameters that can influence the adsorption efficiency of nanofibers such as solution pH, wt.% of prepared nanofibers, drug initial concentration, and contact time were studied and optimized. The results show that the equilibrium adsorption capacity was achieved after only 10 min for 12 wt% PET nanofibers which is equivalent to 364.83 mg/g. For 12 wt% PS nanofibers, an equilibrium adsorption capacity of 328.42 mg/g was achieved in 30 min. The experimental data was fitted to five isotherm and four kinetics models to understand the complicated interaction between the nanofibers and the drug. Langmuir-Freundlich isotherm model showed the best fit for experimental data for both PET and PS nanofibers. The adsorption process was characterized by predominantly physical reaction rather than chemical adsorption for both materials. The reusability study revealed that the synthesized nanofibers maintain their ability to adsorb/desorb IBU for up to five cycles. The results obtained demonstrated that fabricated nanofibers from plastic wastes could perform promising adsorbents for the management of IBU in wastewater. However, further research is needed for the scaling-up the fabrication which is required for real-world applications.


Assuntos
Ibuprofeno , Nanofibras , Polietilenotereftalatos , Poliestirenos , Águas Residuárias , Poluentes Químicos da Água , Nanofibras/química , Ibuprofeno/química , Águas Residuárias/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/análise , Adsorção , Polietilenotereftalatos/química , Poliestirenos/química , Cinética , Purificação da Água/métodos , Eliminação de Resíduos Líquidos/métodos , Espectroscopia de Infravermelho com Transformada de Fourier
18.
Protein Eng Des Sel ; 372024 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-38713696

RESUMO

Plastic degrading enzymes have immense potential for use in industrial applications. Protein engineering efforts over the last decade have resulted in considerable enhancement of many properties of these enzymes. Directed evolution, a protein engineering approach that mimics the natural process of evolution in a laboratory, has been particularly useful in overcoming some of the challenges of structure-based protein engineering. For example, directed evolution has been used to improve the catalytic activity and thermostability of polyethylene terephthalate (PET)-degrading enzymes, although its use for the improvement of other desirable properties, such as solvent tolerance, has been less studied. In this review, we aim to identify some of the knowledge gaps and current challenges, and highlight recent studies related to the directed evolution of plastic-degrading enzymes.


Assuntos
Evolução Molecular Direcionada , Engenharia de Proteínas , Evolução Molecular Direcionada/métodos , Plásticos/química , Plásticos/metabolismo , Polietilenotereftalatos/química , Polietilenotereftalatos/metabolismo , Enzimas/genética , Enzimas/química , Enzimas/metabolismo
19.
Artigo em Inglês | MEDLINE | ID: mdl-38693670

RESUMO

Polyethylene terephthalate (PET) is a common plastic widely used in food and beverage packaging that poses a serious risk to human health and the environment due to the continual rise in its production and usage. After being produced and used, PET accumulates in the environment and breaks down into nanoplastics (NPs), which are then consumed by humans through water and food sources. The threats to human health and the environment posed by PET-NPs are of great concern worldwide, yet little is known about their biological impacts. Herein, the smallest sized PET-NPs so far (56 nm) with an unperturbed PET structure were produced by a modified dilution-precipitation method and their potential cytotoxicity was evaluated in Saccharomyces cerevisiae. Exposure to PET-NPs decreased cell viability due to oxidative stress induction revealed by the increased expression levels of stress response related-genes as well as increased lipid peroxidation. Cell death induced by PET-NP exposure was mainly through apoptosis, while autophagy had a protective role.


Assuntos
Estresse Oxidativo , Polietilenotereftalatos , Saccharomyces cerevisiae , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Polietilenotereftalatos/toxicidade , Nanopartículas/toxicidade , Apoptose/efeitos dos fármacos , Microplásticos/toxicidade , Peroxidação de Lipídeos/efeitos dos fármacos
20.
Sci Rep ; 14(1): 11089, 2024 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-38750101

RESUMO

This investigation explored the presence of microplastics (MPs) and artificial cellulosic particles (ACPs) in commercial water marketed in single use 1.5 L poly(ethylene terephthalate) bottles. In this work we determined a mass concentration of 1.61 (1.10-2.88) µg/L and 1.04 (0.43-1.82) µg/L for MPs and ACPs respectively in five top-selling brands from the Spanish bottled water market. Most MPs consisted of white and transparent polyester and polyethylene particles, while most ACPs were cellulosic fibers likely originating from textiles. The median size of MPs and ACPs was 93 µm (interquartile range 76-130 µm) and 77 µm (interquartile range 60-96 µm), respectively. Particle mass size distributions were fitted to a logistic function, enabling comparisons with other studies. The estimated daily intake of MPs due to the consumption of bottled water falls within the 4-18 ng kg-1 day-1 range, meaning that exposure to plastics through bottled water probably represents a negligible risk to human health. However, it's worth noting that the concentration of plastic found was much higher than that recorded for tap water, which supports the argument in favour of municipal drinking water.


Assuntos
Água Potável , Microplásticos , Poluentes Químicos da Água , Microplásticos/análise , Água Potável/química , Água Potável/análise , Espanha , Poluentes Químicos da Água/análise , Celulose/química , Celulose/análise , Humanos , Tamanho da Partícula , Polietilenotereftalatos/química , Polietilenotereftalatos/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...