Toxic mechanism in Daphnia magna due to phthalic acid esters and CuO nanoparticles co-exposure: The insight of physiological, microbiomic and metabolomic profiles.

Various phthalic acid esters (PAEs) such as dibutyl phthalate (DBP) and butyl benzyl phthalate (BBP) co-exist with nanopollutants in aquatic environment. In this study, Daphnia magna was exposed to nano-CuO and DBP or BBP at environmental relevant concentrations for 21-days to investigate these combined toxic effects. Acute EC50 values (48 h) of nano-CuO, DBP, and BBP were 12.572 mg/L, 8.978 mg/L, and 4.785 mg/L, respectively. Results showed that co-exposure with nano-CuO (500 µg/L) for 21 days significantly enhanced the toxicity of DBP (100 µg/L) and BBP (100 µg/L) to Daphnia magna by 18.37% and 18.11%, respectively. The activities of superoxide dismutase, catalase, and glutathione S-transferase were enhanced by 10.95% and 14.07%, 25.63% and 25.91%, and 39.93% and 35.01% in nano-CuO+DBP and nano-CuO+BBP treatments as compared to the individual exposure groups, verifying that antioxidative defense responses were activated. Furthermore, the co-exposure of nano-CuO and PAEs decreased the population richness and diversity microbiota, and changed the microbial community composition in Daphnia magna. Metabolomic analysis elucidated that nano-CuO + PAEs exposure induced stronger disturbance on metabolic network and molecular function, including amino acid, nucleotides, and lipid metabolism-related metabolic pathways, as comparison to PAEs single exposure treatments. In summary, the integration of physiological, microflora, and untargeted metabolomics analysis offers a fresh perspective into the potential ecological risk associated with nanopollutants and phthalate pollution in aquatic ecosystems.

Association of phthalate exposure with type 2 diabetes and the mediating effect of oxidative stress: A case-control and computational toxicology study.

Phthalic acid esters (PAEs) are widely used as plasticizers and have been suggested to engender adverse effects on glucose metabolism. However, epidemiological data regarding the PAE mixture on type 2 diabetes (T2DM), as well as the mediating role of oxidative stress are scarce. This case-control study enrolled 206 T2DM cases and 206 matched controls in Guangdong Province, southern China. The concentrations of eleven phthalate metabolites (mPAEs) and the oxidative stress biomarker 8-hydroxy-2'-deoxyguanosine (8-OHdG) in urine were determined. Additionally, biomarkers of T2DM in paired serum were measured to assess glycemic status and levels of insulin resistance. Significantly positive associations were observed for mono-(2-ethylhexyl) phthalate (MEHP) and Mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) with T2DM (P < 0.001). Restricted cubic spline modeling revealed a non-linear dose-response relationship between MEHHP and T2DM (Pnon-linear = 0.001). The Bayesian kernel machine regression and quantile g-computation analyses demonstrated a significant positive joint effect of PAE exposure on T2DM risk, with MEHHP being the most significant contributor. The mediation analysis revealed marginal evidence that oxidative stress mediated the association between the mPAEs mixture and T2DM, while 8-OHdG respectively mediated 26.88 % and 12.24 % of MEHP and MEHHP on T2DM risk individually (Pmediation < 0.05). Di(2-ethylhexyl) phthalate (DEHP, the parent compound for MEHP and MEHHP) was used to further examine the potential molecular mechanisms by in silico analysis. Oxidative stress may be crucial in the link between DEHP and T2DM, particularly in the reactive oxygen species metabolic process and glucose import/metabolism. Molecular simulation docking experiments further demonstrated the core role of Peroxisome Proliferator Activated Receptor alpha (PPARα) among the DEHP-induced T2DM. These findings suggest that PAE exposure can alter oxidative stress via PPARα, thereby increasing T2DM risk.

Mechanisms and high-value applications of phthalate isomers degradation pathways in bacteria.

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.

Levels, distribution, and health risk assessment of phthalic acid esters in urban surface soils of Nagpur city, India.

Surface soil samples from residential, commercial, and industrial areas of Nagpur city, India, were collected to study the levels, distribution, and impact of land use patterns on phthalic acid ester (PAEs) contamination. The Σ6PAEs concentrations in soils from residential, commercial, and industrial areas ranged between 6,493 to 13,195 µg/kg, 707 to 18,446 µg/kg, and 1,882 to 5,004 µg/kg with medians of 10,399, 6,199, and 3,401 µg/kg, respectively. Bis-2-ethylhexyl phthalate (DEHP) and dimethyl phthalate (DMP) were the dominant PAEs in the urban soils. The concentrations of DEHP and DMP were significantly greater than those in Ontario's soil quality guidelines. Among the PAEs, benzyl-butyl phthalate (BzBP) was found at relatively high concentrations (1,238 and 9,171 µg/kg) at two locations (i.e., S1 and S15). The chronic toxic risk (CTR) of PAEs was below the threshold, although the risk to children through ingestion and dermal exposure routes was greater than that to adults. The CR due to BzBP and DEHP were below the threshold level; however, the CR due to DMP was > 1 × 10-6 in residential areas. The cumulative CR of the six PAEs for adults (1.33-1.41 × 10-5) and children (8.08-8.89 × 10-6) surpassed the threshold level. This study revealed that PAEs in urban soils pose a risk to public health and require immediate risk reduction strategies.

Evaluation of distinct molecular architectures and coordinated regulation of the catabolic pathways of oestrogenic dioctyl phthalate isomers in Gordonia sp.

Bacterial strain GONU, belonging to the genus Gordonia, was isolated from a municipal waste-contaminated soil sample and was capable of utilizing an array of endocrine-disrupting phthalate diesters, including di-n-octyl phthalate (DnOP) and its isomer di(2-ethylhexyl) phthalate (DEHP), as the sole carbon and energy sources. The biochemical pathways of the degradation of DnOP and DEHP were evaluated in strain GONU by using a combination of various chromatographic, spectrometric and enzymatic analyses. Further, the upregulation of three different esterases (estG2, estG3 and estG5), a phthalic acid (PA)-metabolizing pht operon and a protocatechuic acid (PCA)-metabolizing pca operon were revealed based on de novo whole genome sequence information and substrate-induced protein profiling by LC-ESI-MS/MS analysis followed by differential gene expression by real-time PCR. Subsequently, functional characterization of the differentially upregulated esterases on the inducible hydrolytic metabolism of DnOP and DEHP revealed that EstG5 is involved in the hydrolysis of DnOP to PA, whereas EstG2 and EstG3 are involved in the metabolism of DEHP to PA. Finally, gene knockout experiments further validated the role of EstG2 and EstG5, and the present study deciphered the inducible regulation of the specific genes and operons in the assimilation of DOP isomers.

Current Sample Preparation Methods and Determination Techniques for the Determination of Phthalic Acid Ester Plasticizers in Edible Oils.

In the process of production, processing, transportation, and storage of edible oils, the oils inevitably come into contact with plastic products. As a result, plasticizers migrate into edible oils, are harmful to human health, and can exhibit reproductive toxicity. Therefore, the determination of plasticizers in edible oils is very important, and a series of sample preparation methods and determination techniques have been developed for the determination of plasticizers in edible oils. Phthalic acid ester (PAE) plasticizers are the most widely used among all plasticizers. This review aims to provide a comprehensive overview of the sample preparation methods and detection techniques reported for the determination of PAEs in edible oils since 2010, focusing on sample preparation methods of edible oils combined with various separation-based analytical techniques, such as gas chromatography (GC) and liquid chromatography (LC) with different detectors. Furthermore, the advantages, disadvantages, and limitations of these techniques as well as the prospective future developments are also discussed.

Ethane-bridge periodic mesoporous organosilica materials as a novel fiber coating in headspace solid-phase microextraction of phthalate esters from saliva and PET container samples.

The current study presents a periodic mesoporous organosilica (PMO) with a high surface area and uniform-porosity material. The PMO materials were successfully synthesized and modified. The resultant material was characterized by different characterization techniques. The prepared PMO was immobilized on a stainless steel wire surface and was evaluated for headspace solid-phase microextraction of the ultra-trace amount of phthalate esters from saliva and polyethylene terephthalate containers which were in contact with hot and cold water. Separation and determination of the phthalate esters (PEs) were performed by the GC-FID and GC-MS instruments. The key parameters affecting the extraction efficiencies, including extraction temperature, extraction time, ionic strength, and desorption temperature and time, were investigated and optimized. Under optimum conditions, the repeatability for one fiber (n = 7) was 4.8-8.7%, and fiber-to-fiber reproducibility (n = 3) was 7.5-10.6% for the extracted compounds. The limits of detection of the developed method for the studied compounds were between 0.01 and 1 µg L-1. The results showed suitable coefficients of determination (R2 ≥ 0.99) for all of the analytes in the 0.05-300 µg L-1 calibration range. Acceptable recovery values of 91-107%, 82-110%, and 98-104% were obtained in saliva, polyethylene terephthalate containers hot water, and cold water, respectively.

Matrix compatibility of typical sol-gel solid-phase microextraction coatings in undiluted plasma and whole blood for the analysis of phthalic acid esters.

Sol-gel materials have been widely used for solid-phase microextraction (SPME) coatings due to their outstanding performance; in contrast, sol-gel SPME coatings have seldom been used for in vivo sampling. The main reason is that their matrix compatibility is unclear. In order to promote the application of this type of coating and accelerate the development of in vivo SPME, in this study, the matrix compatibility of several typical sol-gel coatings was assessed in plasma and whole blood using phthalic acid esters as analytes. The service life of five kinds of sol-gel coatings was among 20-35 times in undiluted plasma, while it was 27 times for a homemade commercial polydimethylsiloxane coating, which indicates good matrix compatibility of sol-gel coatings in untreated plasma. The sol-gel hydroxy-terminated silicone oil/methacrylic acid fiber achieved the highest extraction ability among all of the fibers, and it was tested in pig whole blood. It could be continuously used for at least 22 times, demonstrating good potential for in vivo sampling. Subsequently, a direct-immersion SPME/gas chromatography-flame ionization detection method was established for the determination of 5 phthalic acid esters in blood. Compared with other methods reported in the literature, this method is rapid, simple, sensitive, and accurate, and does not need expensive instruments or tedious procedures. A simulation system of animal blood circulation was constructed to verify the practicability of sol-gel SPME coatings in animal vein sampling. The result illustrated the feasibility of that coating for in vivo blood sampling, but a more accurate quantification calibration approach needs to be explored.

Occurrence, distribution and sources of phthalates and petroleum hydrocarbons in tropical estuarine sediments (Mandovi and Ashtamudi) of western Peninsular India.

The present study provides baseline information on the concentration levels, distribution characteristics and pollution sources of environmental contaminants, such as phthalic acid esters (PAEs or phthalates) and petroleum hydrocarbons in surface sediments of the tropical estuaries (Mandovi and Ashtamudi) from western Peninsular India. Total PAEs (∑5PAEs), hopanes, steranes and diasteranes concentrations from Ashtamudi estuary ranged from 7.77 to 1478.2 ng/g, n.d.-363.2 ng/g, n.d.-121.5 ng/g and n.d.-116.6 ng/g, respectively. Likewise, PAEs (∑6PAEs), steranes and diasteranes concentrations from Mandovi estuary ranged from 60.1 to 271.9 ng/g, 2.33-40.1 ng/g and 2.28-23.0 ng/g, respectively. The PAEs comprising di-isobutyl phthalate (DIBP), dibutyl phthalate (DBP), an isomer peak for DBP, di(2-ethylhexyl) phthalate (DEHP), di-isononyl phthalate were dominant in Ashtamudi estuary sediments, while PAEs including diethyl phthalate, DIBP, DBP and its isomer, DEHP, di(2-ethylhexyl) terephthalate were detected in the Mandovi sediment samples. The results of this study show an insignificant correlation of TOC with PAEs, and indicates that the varying spatial distributions of the PAEs in both the estuaries can be the result of discharge sources. The higher concentration of PAE congeners was noticed in Ashtamudi, a Ramsar wetland site, that can be attributed to land-based plastic waste. The petroleum biomarkers were abundantly present in Mandovi estuary due to anthropogenic activities such as boating and spillage from oil tankers. The findings of the present study will serve as a reference point for future investigation of organic contaminants in Indian estuaries, and calls for attention towards implementing effective measures in controlling the pervasion of the PAEs and petroleum biomarkers.

Spatial distribution model of DEHP contamination categories in soil based on Bi-LSTM and sparse sampling.

Soil pollution is a serious threat to human life and development. Different remedial measures are applied to soils with different levels of contamination. The degree of soil contamination in different areas is generally evaluated and categorised based on the analysis of samples. Regional soil sampling sites are generally sparse because of the cost of sampling and other factors, which makes it difficult to accurately assess the extent of regional soil contamination. In this study, a spatial classification model was established for the Di(2-ethylhexyl) phthalate (DEHP) pollution level using a Bi-directional Long Short-Term Memory (Bi-LSTM) neural network considering that the sampling information gradually diminishes with increasing distance between the sampling and prediction points. In this study, a method is proposed for the prediction of the spatial distribution of soil pollution categories based on sparse samples. We also established a model for the spatial distribution of organic pollution categories. The analysis of an actual contaminated area shows that the DEHP concentrations at different locations can be effectively predicted with the proposed method by categorising the contamination levels of specific DEHP samples. The results show that the method can be used to classify the degree of light/severe DEHP contamination. The results are in good agreement with the actual situation, verifying the validity of the method. This method is important for the rapid assessment of the spatial distribution of soil contamination levels based on sparse sampling.

Microbiology combined with metabonomics revealing the response of soil microorganisms and their metabolic functions exposed to phthalic acid esters.

As microplastics became the focus of global attention, the hazards of plastic plasticizers (PAEs) have gradually attracted people's attention. Agricultural soil is one of its hardest hit areas. However, current research of its impact on soil ecology only stops at the microorganism itself, and there is still lack of conclusion on the impact of soil metabolism. To this end, three most common PAEs (Dimethyl phthalate: DMP, Dibutyl phthalate: DBP and Bis (2-ethylhexyl) phthalate: DEHP) were selected and based on high-throughput sequencing and metabolomics platforms, the influence of PAEs residues on soil metabolic functions were revealed for the first time. PAEs did not significantly changed the alpha diversity of soil bacteria in the short term, but changed their community structure and interfered with the complexity of community symbiosis network. Metabolomics indicated that exposure to DBP can significantly change the soil metabolite profile. A total of 172 differential metabolites were found, of which 100 were up-regulated and 72 were down-regulated. DBP treatment interfered with 43 metabolic pathways including basic metabolic processes. In particular, it interfered with the metabolism of residual steroids and promoted the metabolism of various plasticizers. In addition, through differential labeling and collinear analysis, some bacteria with the degradation potential of PAEs, such as Gordonia, were excavated.

Facile and Selective Determination of Total Phthalic Acid Esters Level in Soft Drinks by Molecular Fluorescence Based on Petroleum Ether Microextraction and Selective Derivation by H2SO4.

Determining the level of phthalic acid esters (PAEs) in packaged carbonated beverages is a current need to ensure food safety. High-selectivity and -accuracy identification of individual PAEs can be achieved by chromatographic and mass spectrometric (MS) techniques. However, these methods are slow; involve complicated, expensive instruments in professional laboratories; and consume a large amount of organic solvents. As such, a food analysis method is needed to conveniently and rapidly evaluate multiple contaminants on site. In this study, with the assistance of ultrasound, we quickly determined the total PAEs in soft drinks using 1.5 mL of petroleum ether in one step. Then, we determined the characteristic molecular fluorescence spectrum of all PAEs in samples (excitation (Ex)/emission (Em) at 218/351 nm) using selectively concentrated sulfuric acid derivatization. The relative standard deviations of the fluorescent intensities of mixed solutions with five different PAEs were lower than 7.1% at three concentration levels. The limit of detection of the proposed method is 0.10 µmol L-1, which matches that of some of the chromatographic methods, but the proposed method uses less organic solvent and cheaper instruments. These microextraction devices and the fluorescence spectrometer are portable and provide an instant result, which shows promise for the evaluation of the total level of PAEs in beverages on site. The proposed method successfully detected the total level of PAEs in 38 kinds of soft drink samples from local supermarkets, indicating its potential for applications in the packaged beverage industry.

Occurrence of Phthalate Acid Esters (PAEs) in Protected Agriculture Soils and Implications for Human Health Exposure.

This study explored occurrence of phthalic acid esters (PAEs) in protected agriculture soils and assessed their potential health risks to humans. Results showed that DEHP and DBP were the most abundant PAEs congeners, with mean concentrations of 318.68 µg/kg and 137.56 µg/kg, respectively. DOP and BBP concentrations were relatively low, and DMP and DEP were not detected in all samples. DBP concentrations were higher than the allowable concentration standard value. Additionally, soil pH and organic matter were key environmental parameters which may play the vital roles to the occurrence of organic pollutants. Heath risk assessment results indicated that dermal contact was the predominant human exposure route under non-dietary conditions, and children obtained higher health risk scores than adults. In summary, the overall health risk scores were at an acceptable level. These results provide insights for assessing soil environmental safety and ecological risks in protected agricultural soil.

Production, Use, and Fate of Phthalic Acid Esters for Polyvinyl Chloride Products in China.

Phthalic acid esters (PAEs) are the most common plasticizers, approximately 90% of which are used in polyvinyl chloride (PVC) products, but they are also endocrine disruptors that have attracted considerable attention. The metabolism of PAEs in PVC products in China from 1958 to 2019 was studied using dynamic material flow analysis. The results showed that the total consumption of PAEs was 29.2 Mt in the past 60 years. By 2019, the in-use stocks of PAEs were 5.0 Mt. Construction materials were always in the leading position with respect to the consumption and in-use stocks of PAEs. A total PAE loss of 22.7 Mt was generated, of which 68.0% remained in waste distributed in landfills (50.1%), storage sites (5.5%), the environment (44.4%), 12.4% was eliminated during waste incineration and open burning, and 19.6% was emitted into the environment. From 1958 to 2019, 496.4, 55.6, and 3905.0 kt of PAEs were emitted into water, air, and soil, respectively. The use and waste treatment stages contributed 79.3 and 19.9% of the emissions of PAEs in the life cycle, respectively. This study systematically analyzed the metabolism of PAEs at the national level over a long-time span, providing useful information on the life cycle management of PAEs.

Quality assessment of environmental water by a simple and fast non-ionic hydrophobic natural deep eutectic solvent-based extraction procedure combined with liquid chromatography tandem mass spectrometry for the determination of plastic migrants.

A non-ionic hydrophobic natural deep eutectic solvent (HNADES) based on thymol and menthol was proposed for the liquid-liquid microextraction of fourteen phthalates and one adipate from environmental water samples. Separation, identification, and quantification were achieved by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry. The main factors affecting the extraction efficiency were thoroughly studied. Sample pH of 8 and 100 µL of thymol:menthol at molar ratio 2:1 were selected as the best conditions, while ionic strength and type of dispersant solvent were not relevant for the extraction of the target compounds. The whole methodology was validated for treated wastewater, runoff, and pond water matrices, using di-n-butyl phthalate-3,4,5,6-d4 and dihexyl phthalate-3,4,5,6-d4 as surrogates. Recovery ranged from 70 to 127% with relative standard deviation values lower than 14%. Limits of quantification of the method were in the range 0.042-0.425 µg/L for treated wastewater, 0.015-0.386 µg/L for runoff, and 0.013-0.376 µg/L for pond water. The methodology was applied for the analysis of real treated wastewater, runoff, and pond water samples from different places of Tenerife and Gran Canaria (Canary Islands) finding the presence of diethyl phthalate, diallyl phthalate, dipropyl phthalate, benzylbutyl phthalate, di-n-butyl phthalate, bis-(2-n-butoxyethyl) phthalate, di-n-pentyl phthalate, dicyclohexyl phthalate, and bis-(2-ethylhexyl) phthalate at concentrations between 105.2 and 3414 ng/L.

Sorption of diethyl phthalate and cadmium by pig carcass and green waste-derived biochars under single and binary systems.

Potentially toxic elements (PTEs) and phthalic acid esters (PAEs) often coexist in contaminated soils. Their co-existence may affect the mutual sorption behavior, and thereby influence their bioavailability and fate in soils. To our best knowledge, the impacts of plant-and animal-derived biochar on the competitive sorption-desorption of PTEs and PAEs in soils with different organic carbon content have not been studied up to date. Therefore, in this study, batch sorption-desorption experiments were conducted to investigate the influence of biochars derived from pig carcass and Platanus orientalis branches on the mono- and competitive sorption of cadmium (Cd2+) and diethyl phthalate (DEP) in soils with high (HS) and low (LS) organic carbon content. The DEP sorption was well described by Freundlich isotherm model, while Cd2+ sorption fitted better with the Langmuir isotherm model. Application of both biochars enhanced soil sorption of DEP, which increased as the application doses increased. The HS showed a stronger affinity to both DEP and Cd2+ than the LS. In the LS, the pig carcass biochar (PB) addition was more effective to increase the sorption capacity of Cd2+ and DEP and to reduce their desorption than woody biochar (WB) treatments. Moreover, the co-existing of Cd2+ could reduce the sorption of DEP, especially in the LS. The presence of DEP enhanced Cd2+ sorption in LS treated by both biochars, but the sorption of Cd2+ was suppressed with DEP addition in the PB-amended HS. In conclusion, the soil sorption capacity of DEP and Cd2+ was affected by biochar type, application dose and soil organic carbon content. The reciprocal effect between DEP and Cd2+ was also a crucial factor influencing their sorption/desorption by biochar. Therefore, PB and WB, especially PB, can be used for metal/DEP immobilization due to enhanced sorption. This approach is applicable for future remediation of soils contaminated by PTEs and PAEs.

Associations between phthalic acid esters in household dust and childhood asthma in Shanghai, China.

Phthalic acid esters (PAEs) have a negative impact on human health and are widely distributed in China. As part of the China, Children, Home, Health (CCHH) study, we investigated the associations between childhood asthmatic symptoms and PAEs in settled house dust in Shanghai, China. We found that di-2-ethylhexyl phthalate (DEHP), dibutyl phthalate (DBP), and diisobutyl phthalate (DiBP) were abundant in the indoor environment. A total of 27 % of children suffered from diagnosed asthma. The Mann-Whitney U test and multiple logistic regression were used to obtain the associations between PAEs and childhood asthmatic symptoms. Stratification analysis was performed to reveal the influence of gender on the associations between PAE exposure and target symptoms. Compared with low concentrations of PAEs, high concentrations of high molecular weight PAEs (HMW-PAEs) were significantly associated with childhood diagnosed asthma (adjusted odds ratios (AORs) > 1, P < 0.05). Moreover, significantly negative associations were found between high concentrations of DiBP and current cough (AORs<1, P < 0.05). All significantly positive associations were observed among girls, and most of the associations of dimethyl phthalate (DMP) and diethyl phthalate (DEP) exposure with the studied symptoms among girls were higher than those among boys. Exposure to PAEs may be a risk factor for asthmatic symptoms in children, especially in girls.

Evaluation of the Removal of Selected Phthalic Acid Esters (PAEs) in Municipal Wastewater Treatment Plants Supported by Constructed Wetlands.

Phthalic acid esters (PAEs) have a negative impact on living organisms in the environment, therefore, are among the group of Endocrine Disrupting Compounds (ECDs). Unfortunately, conventional methods used in municipal wastewater treatment plants (MWWTPs) are not designed to eliminate PAEs. For this reason, the development of cheap and simple but very effective techniques for the removal of such residues from wastewater is crucial. The main aim of this study was the evaluation of the removal of six selected PAEs: diethyl phthalate (DEP), di-n-octyl phthalate (DOP), di-n-butyl phthalate (DBP), benzyl butyl phthalate (BBP), bis(2-ethylhexyl) phthalate (DEHP) and dimethyl phthalate (DMP), in real MWWTPs supported by constructed wetlands (MWWTP-CW system). For the first time, the possibility of using three new plants for this purpose, Cyperus papyrus (papyrus), Lysimachia nemorum (yellow pimpernel) and Euonymus europaeus (European spindle), has been presented. For determining the target PAEs in wastewater samples, a method of SPE (Solid-Phase Extraction)-GC-MS(SIM) was developed and validated, and for plant materials, a method of UAE (Ultrasound-Assisted Extraction)-SPE-GC-MS(SIM) was proposed. The obtained data showed that the application of the MWWTP-CW system allows a significant increase in the removal of DEP, DBP, BBP and DEHP from the wastewater stream. Euonymus europaeus was the most effective among the tested plant species for the uptake of analytes (8938 ng × g-1 dry weight), thus, this plant was found to be optimal for supporting conventional MWWTPs.

Development of a whole-cell biocatalyst for diisobutyl phthalate degradation by functional display of a carboxylesterase on the surface of Escherichia coli.

BACKGROUND: Phthalic acid esters (PAEs) are widely used as plasticizers or additives during the industrial manufacturing of plastic products. PAEs have been detected in both aquatic and terrestrial environments due to their overuse. Exposure of PAEs results in human health concerns and environmental pollution. Diisobutyl phthalate is one of the main plasticizers in PAEs. Cell surface display of recombinant proteins has become a powerful tool for biotechnology applications. In this current study, a carboxylesterase was displayed on the surface of Escherichia coli cells, for use as whole-cell biocatalyst in diisobutyl phthalate biodegradation. RESULTS: A carboxylesterase-encoding gene (carEW) identified from Bacillus sp. K91, was fused to the N-terminal of ice nucleation protein (inpn) anchor from Pseudomonas syringae and gfp gene, and the fused protein was then cloned into pET-28a(+) vector and was expressed in Escherichia coli BL21(DE3) cells. The surface localization of INPN-CarEW/or INPN-CarEW-GFP fusion protein was confirmed by SDS-PAGE, western blot, proteinase accessibility assay, and green fluorescence measurement. The catalytic activity of the constructed E. coli surface-displayed cells was determined. The cell-surface-displayed CarEW displayed optimal temperature of 45 °C and optimal pH of 9.0, using p-NPC2 as substrate. In addition, the whole cell biocatalyst retained ~ 100% and ~ 200% of its original activity per OD600 over a period of 23 days at 45 °C and one month at 4 °C, exhibiting the better stability than free CarEW. Furthermore, approximately 1.5 mg/ml of DiBP was degraded by 10 U of surface-displayed CarEW cells in 120 min. CONCLUSIONS: This work provides a promising strategy of cost-efficient biodegradation of diisobutyl phthalate for environmental bioremediation by displaying CarEW on the surface of E. coli cells. This approach might also provide a reference in treatment of other different kinds of environmental pollutants by displaying the enzyme of interest on the cell surface of a harmless microorganism.

Physiological responses of Arthrobacter sp. JQ-1 cell interfaces to co-existed di-(2-ethylhexyl) phthalate (DEHP) and copper.

Arthrobacter sp. JQ-1 can completely degrade 500 mg/L of DEHP within 3 days. The minimum inhibitory concentrations (MICs) of Cu2+ could reach 1.56 mM, however, 5.0 mg/L Cu2+ apparently inhibited DEHP degradation and bacterial growth. Consequently, JQ-1 was exposed to the DEHP-copper environment to verify the toxicity mechanism based on the physiological responses of cellular multiple interfaces (cellular surface, membrane and intracellular characteristics). The results showed the combination of 500 mg/L DEHP and 5.0 mg/L Cu2+ significantly decreased cell surface hydrophobicity (CSH) and the absolute value of zeta potential, which implied the bioavailability of DEHP was decreased. The cellular surface changes were mainly due to the interaction between Cu2+ and some functional groups (CH2, CH3, aromatic rings, and amide). The weakened proton-motive force (PMF) across the plasma membrane may interfere the formation and utilization of energy, which is not conducive to the repair process of cellular damages. In this study, Non-invasive micro-test technology (NMT) was applied to the research of combined toxicity of DEHP and heavy metal ions for the first time. DEHP-copper intensified K+ efflux and Ca2+ influx across the plasma membrane, which disturbed ion homeostasis of K+ and Ca2+ and might induce apoptosis and further inhibit DEHP degradation. The decline of intracellular esterase activity indicated that the metabolic capacity is apparently restrained. This study enhances our understanding of cellular different interface processes responding to combined pollutants.