E2 Removal Research Articles

Unlocking the roles of wheat root exudates in regulating laccase-catalyzed estrogen humification

While laccase humification has an efficient capacity to convert estrogenic pollutants, the roles of wheat (Triticum aestivum L.) root exudates (W-REs) in the enzymatic humification remain poorly understood. Herein, we presented the research into the effects of W-REs on 17β-estradiol (E2) and bisphenol A (BPA) conversion in vitro laccase humification. W-REs inhibited E2 removal but promoted BPA conversion in the enzymatic humification, and the first-order kinetic constants for E2 and BPA were 0.27–0.69 and 0.28–0.55 h−1, respectively. Specialized small phenols and amino acids in W-REs were susceptible to laccase humification, resulting in increased copolymerization of estrogen and W-REs. In greenhouse hydroponics, the accumulated amounts of E2 (BPA) in the roots and shoots were estimated to be 0.87 (2.15) and 0.43 (0.51) nmol·plant−1 at day 3, respectively. By forming low- and eventually non-toxic copolymeric precipitates between estrogen and W-REs, laccase humification lowered the phytotoxicity and bioavailability of estrogen in the rhizosphere solution, consequently relieving its uptake, accumulation, and distribution in the wheat cells. This work sheds light on the roles of W-REs in regulating laccase-catalyzed estrogen humification, and gives an insight into the path of addressing organic contamination in the rhizosphere and ensuring food safety.

Adsorption of steroid hormone micropollutant by polyethersulfone ultrafiltration membranes with varying morphology

The effective removal of micropollutants necessitates the use of dense membranes, such as thin-film composite (TFC) reverse osmosis (RO) and nanofiltration (NF) membranes. TFCs have a polyamide active layer interfacially polymerized on a support layer that is typically made of polysulfone (PSu) or polyethersulfone (PES). Retention by NF and RO is often incomplete because micropollutants are adsorbed to the polymer material and subsequently permeate via a combination of convection and diffusion, which evidences a breakthrough curve. When describing breakthrough phenomena, the role of the support membrane is commonly neglected, even though the adsorption in this layer can be significant. This work investigated the adsorption of steroid hormone micropollutants (17β-estradiol, E2) by fabricated and commercial PES ultrafiltration membranes with varying morphology.By increasing the coagulation bath temperature between 10 and 70 °C, the pure water permeability increased from 13 to 3800 L/m2·h−1·bar−1, and consequently, the average pore size rose from 12 to 191 nm. The fabricated membranes with smaller pore sizes showed higher E2 removal via adsorption which can be attributed to the higher internal surface area. The adsorbed mass of fabricated PES membranes (using dimethylformamide (coded as PDG) and N-methyl-2-pyrrolidone (coded as PNG) and PES (Istanbul Technical University (ITU), with non-woven supports) varies from 0.30 to 0.60, 0.27–0.60 and 1–1.2 ng·cm−2, respectively. These values are lower than the adsorbed masses with commercial Biomax (Millipore Inc.) membranes (0.5–2.0 ng·cm−2). Ultrafiltration membranes used as support for composite membranes, nanofiltration or as filters in sample preparation benefit from lower micropollutant adsorption.

Heterostructure g-C3N4/Bi2MoO6 PVDF nanofiber composite membrane for the photodegradation of steroid hormone micropollutants

Photocatalytic membrane reactors (PMRs) are a promising technology for micropollutant removal. Sunlight utilization and catalyst surface sites limit photodegradation. A poly(vinylidene fluoride) (PVDF) nanofiber composite membrane (NCM) with immobilized visible-light-responsive g-C3N4/Bi2MoO6 (BMCN) were developed. Photodegradation of steroid hormones with the PVDF-BMCN NCM was investigated with varying catalyst properties, operating conditions, and relevant solution chemistry under solar irradiation. Increasing CN ratio (0–65 %) enhanced estradiol (E2) degradation from 20 ± 10 to 75 ± 7 % due to improved sunlight utilization and photon lifetime. PVDF nanofibers reduced self-aggregation of catalysts. Hydraulic residence time and light intensity enhanced the photodegradation. With the increasing pH value, the E2 removal decreased from 84 ± 4 to 67 ± 7 % owing to electrical repulsion and thus reduced adsorption between catalysts and E2. A removal of 96 % can be attained at environmentally relevant feed concentration (100 ng.L–1) with a flux of 60 L.m−2.h−1, irradiance of 100 mW.cm−2, and 1 mg.cm−2 BMCN65 loading. This confirmed that heterojunction photocatalysts can enhance micropollutants degradation in PMRs.

Facile synthesis of PA photocatalytic membrane based on C-PANI@BiOBr heterostructures with enhanced photocatalytic removal of 17β-estradiol

The prevalence of 17β-estradiol (E2) in wastewater has attracted widespread attention due to the negative impacts on ecological environments and human health. Nowadays, photocatalysis has been emerged as an efficient technology for E2 containing wastewater treatment. However, traditional powder photocatalysts face challenges such as easy agglomeration, secondary pollution and difficult recovery, limiting their large-scale application. In this study, a photocatalytic PA/C-PANI@BiOBr membrane was fabricated by immobilizing polyaniline (PANI) layer and BiOBr nanosheets on polyamide (PA) membrane through in-situ chemical bath deposition. This process leveraged the strong hydrogen bond interaction between PANI and PA, with the fine PANI fibers providing nucleation sites for the in-situ growth of BiOBr nanosheets. By repeating the immersion process, we controlled variations in the coverage density and morphology of BiOBr on the membrane surface. The PA/C-PANI@BiOBr membrane exhibited outstanding light absorption and photocatalytic performance. Notably, the optimal PA/C-PANI@BiOBr-10 membrane achieved 100 % removal efficiency of 3 mg L−1 E2 within 40 min. In dynamic cyclic experiments, PA/C-PANI@BiOBr-10 membrane maintained stable permeability and high removal efficiency of pollutants. The photocatalytic mechanism underlying these results was elucidated through photoelectric testing and further photocatalytic experiments. Furthermore, the PA/C-PANI/BiOBr-10 membrane demonstrated remarkable durability over multiple consecutive cycles, with E2 removal efficiency remaining above 96.5 % after 5 cycles.

17β-estradiol (E2) removal in anode-electrodialysis (anode-ED) during nutrient recovery from pig manure digestate

Nutrient recovery from anaerobic digestate through electrodialysis technology (ED) has been investigated and shown high promise, but the removal of 17β-estradiol (E2), which is a natural estrogen and widely found in manure digestate, is not clear. This study examined the mechanism of membrane adsorption and anodic oxidation of E2 during recovering nutrient from manure digestate, and further investigated the performance of Anode-ED in E2 removal. The results showed that the removal of E2 in conventional ED was primarily attributed to membrane adsorption, resulting in no detectable E2 in the product solution. The adsorption capacity of the anion exchange membrane for E2 was significantly higher compared to that of the cation exchange membrane. During Anode-ED operation, E2 was efficiently removed by electrochemical oxidation, in which the chlorination played a primary role. Moreover, the oxidation intermediates of E2 were further removed after 40 min. Even though the carbonate, volatile fatty acid (VFA), and humic acid in the real wastewater have a negative impact on E2 oxidation, the E2 was completely removed from digestate during nutrient recovery in the anode-ED. This study indicates that anode-ED is a promising technology for the removal of E2 during nutrient recovery from digestate.

Photocatalytic removal of 17β-estradiol from water using a novel bimetallic NiCu/Nb2O5 catalyst.

The development of effective photocatalytic materials is essential for removing emerging pollutants from aqueous media, such as the hormone 17β-estradiol (E2). In this study, a novel photocatalyst based on niobium pentoxide (Nb2O5) functionalized with nickel (Ni) and copper (Cu) was synthesized for E2 removal. The NiCu/Nb2O5 photocatalyst was prepared using a facile wet impregnation method and characterized by various techniques. The incorporation of Ni and Cu into Nb2O5 reduced the band gap energy from 3.3 to 2.8eV, enabling efficient utilization of visible light. Moreover, NiCu/Nb2O5 exhibited the highest E2 removal efficiency (82%) under UV-A-assisted conditions at a concentration of 1.5 g L-1. The reaction kinetics were found to follow a second-order model with a rate constant of k = 0.0020 L g-1 min-1, and a plausible reaction mechanism was proposed. Through the study of radical elimination, it was proven that the radical oxidation reaction mechanism predominated in the reaction. The results of the toxicity assays, combined with the TOC parameter, demonstrated the efficacy of photocatalytic degradation in reducing E2. These findings demonstrate the great potential of the NiCu/Nb2O5 photocatalyst for removing persistent pollutants.

Mechanism for removing 17beta-estradiol by bio-nanocomposite FJ1@rGO based on integration of adsorption and biodegradation

17beta-estradiol (E2) is classified as an endocrine disruptor and it poses a significant threat to the environment. Despite our previous work on the preparation of green-reduced graphene immobilized Ochrobactrum sp. FJ1(FJ1@rGO) to achieve high efficiency in removing E2, the functions of strain FJ1 and rGO, as well as their removal mechanism of E2, remain not well understood. In this study, FJ1@rGO was used to remove E2 to comprehend the removal mechanism where efficiency was found to be 93.74% after 10 days of removal compared to only rGO (43.82%). This indicated that E2 degradation was based on the integration of adsorption using rGO and biodegradation through strain FJ1, as evidenced by HPLC-UV. Additionally, results confirmed that the E2 removal process by FJ1@rGO conforms to first-order degradation kinetics and pseudo-second-order kinetics, further demonstrating the synergistic effect of physical adsorption and biodegradation. LC-Q/TOF-MS analysis identified the primary degradation products as estrone (E1), 4-OH-E1, and catechol. Combining characterization analysis, rGO facilitates the transfer of electrons between cells and E2, improving the strain's tolerance of environmental changes. Finally, the assessment of various wastewaters showed that the removal efficiency was 99.76%, 96.89%, and 78.09%, respectively. Overall, the mechanism by FJ1@rGO to remove E2 was proposed here, providing new insights into green and sustainable technology for treating E2 in wastewater.

Influence of organic matter on the photocatalytic degradation of steroid hormones by TiO2-coated polyethersulfone microfiltration membrane

Water treatment in photocatalytic membrane reactors (PMR) holds great promise for removing micropollutants from aquatic environments. Organic matter (OM) that is present in any water matrix may significantly interfere with the degradation of steroid hormone (SH) micropollutants in PMRs. In this study, the interference of various OM types, humic acid (HA), Australian natural organic matter (AUS), worm farm extract (WF), tannic acid (TA), and gallic acid (GA) with the SH degradation at its environmentally relevant concentration (100 ng/L) in a flow-through PMR equipped with a polyethersulphone-titanium dioxide (PES-TiO2) membrane operated under UV light (365 nm) was investigated. Results of this study showed that OM effects are complex and depend on OM type and concentration. The removal of β-estradiol (E2) was enhanced by HA at its levels below 5 mgC/L while the enhancement was abated at higher HA concentrations. The E2 removal was inhibited by TA, and GA, while no significant interference observed for AUS, and WF. The data demonstrated diverse roles of OM that acts in PMRs as a light screening agent, a photoreactive species scavenger, an adsorption alteration trigger, and a photosensitizer. The time-resolved fluorescence measurement showed that HA, acting as a photosensitizer, promoted the sensitization of TiO2 by absorbing light energy and transferring energy/electron to the TiO2 substrate. This pathway dominated the mechanism of the enhanced E2 degradation by HA. The favorable effect of HA was augmented as increasing the light intensity from 0.5 to 10 mW/cm2 and was weakened at higher light intensities due to the increased scavenging reactions and the limited amount of HA. This work clarifies the underlying mechanism of the OM interference on photocatalytic degradation of E2 by the PES-TiO2 PMR.

Abstract P6-12-02: Connecting Fluctuations in Estrogen Production, Release, and Action with Hormone-Dependent Gene Expression in Breast Cancers

Abstract Estrogens are steroid hormones that play a key role in a wide range of physiological and pathological processes. Estrogen receptor-alpha, ERɑ, functions primarily as a nuclear transcription factor (TF) through ligand-dependent activation by 17β-estradiol (E2), the predominant naturally-occurring estrogen. This results in dimerization, DNA binding to cis-regulatory elements called enhancers, and gene regulatory function of ERɑ. In vivo, E2 production and action fluctuates during reproductive cycles and possibly even in a circadian manner. In tissues and cells, E2-regulated gene expression is dynamic, with rapid induction of enhancer formation and target gene expression (or repression), followed by enhancer “decommissioning” and cessation of the gene regulatory effects. The effects of sustained E2 production and signaling, fluctuations in E2 levels, and removal of E2 on estrogen-regulated gene expression are unknown. Classical experiments exploring the gene regulatory effects of E2 involve stimulation of cultured cells throughout the duration of the experiment with a continuous and typically high dose of hormone, with the cells harvested at the end of the stimulation period. While this has allowed us to understand the molecular underpinnings of signal-dependent transcription, it has not allowed analysis of physiological fluctuations in estrogen signaling involving periods of stimulation (i.e., the presence of hormone) and non-stimulation (i.e., the absence of hormone). In our studies, we are applying a combination of next generation sequencing techniques and fluorescence microscopy to investigate signal-dependent responses to fluctuating and short duration E2 exposures using ERɑ-positive MCF-7 human breast cancer cells after E2 treatment and removal. Our initial results suggest that different E2 target genes respond differently to low dose E2 treatment and E2 withdrawal. Moreover, for some E2 target genes, sustained E2 treatment may not be required for a complete E2 transcriptional response. With these studies, we hope to connect physiological aspects of E2 production, release, and action with the molecular mechanisms of E2-dependent gene expression - an aspect of our understanding of estrogen signaling that has been lacking. Citation Format: Hyung Bum Kim, William L. Kraus. Connecting Fluctuations in Estrogen Production, Release, and Action with Hormone-Dependent Gene Expression in Breast Cancers [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-12-02.

Poly(vinylidene fluoride) membrane with immobilized TiO2 for degradation of steroid hormone micropollutants in a photocatalytic membrane reactor

The lack of effective technologies to remove steroid hormones (SHs) from aquatic systems is a critical issue for both environment and public health. The performance of a flow-through photocatalytic membrane reactor (PMR) with TiO2 immobilized on a photostable poly(vinylidene fluoride) membrane (PVDF-TiO2) was evaluated in the context of SHs degradation at concentrations from 0.05 to 1000 µg/L under UV exposure (365 nm). A comprehensive investigation into the membrane preparation approach, including varying the surface Ti content and distribution, and membrane pore size, was conducted to gain insights on the rate-limiting steps for the SHs degradation. Increasing surface Ti content from 4 % to 6.5 % enhanced the 17β-estradiol (E2) degradation from 46 ± 12–81 ± 6 %. Apparent degradation kinetics were independent of both TiO2 homogeneity and membrane pore size (0.1–0.45 µm). With optimized conditions, E2 removal was higher than 96 % at environmentally relevant feed concentration (100 ng/L), a flux of 60 L/m2h, 25 mW/cm2, and 6.5 % Ti. These results indicated that the E2 degradation on the PVDF-TiO2 membrane was limited by the catalyst content and light penetration depth. Further exploration of novel TiO2 immobilization approach that can offer a larger catalyst content and light penetration is required to improve the micropollutant removal efficiency in PMR.

Dark transformation from 17β-estradiol to estrone initiated by hydroxyl radical in dissolved organic matter

The occurrence and fate of 17β-estradiol (E2) in natural water have gained extensive attention owing to its high ecotoxic risk to wildlife. Dissolved organic matter (DOM) is a ubiquitous water constituent and contributes significantly to E2 removal, although the reaction mechanism is rarely clarified. The present study aims to investigate E2 transformation in water containing fresh or aged DOM surrogates at environmentally relevant concentrations in the dark. Experiments along with radical probes of benzene and furfuryl alcohol reveal that reactive radicals, particularly hydroxyl radical (·OH), formed non-photochemically at higher concentrations in aged DOM than in fresh DOM. The contribution of ·OH in E2 removal is indicated by the decreases in the removal of radical probes in the presence of E2; moreover, E2 removal is inhibited in the presence of radical scavengers. The dose-dependent inhibitive effect of substrate concentrations, including E2 and coexistent propylparaben, shows that the radical concentration is a limiting factor for E2 removal, which could be enhanced by increasing DOM concentration, dissolved oxygen, and light supply. As the main byproduct, estrone (E1) is persistent in the current DOM water in the dark, but it can be easily photodegraded when exposed to light. Theoretical analysis reveals that the initial step is ·OH-initiated H- abstraction on the hydroxyl group in the cyclopentane ring of E2. The formed singlet excited state of E2 undergoes further intramolecular rearrangement and oxidative dehydrogenation to generate E1 and the hydroperoxy radical (·HO2). Considering the universal occurrence of E2 in DOM-rich aquatic matrices, the present findings have special implications for the biogeochemical cycle and risk assessment of this pollutant in natural aquatic environments, particularly those beyond the photic zone.

Manganese redox cycling in immobilized bioreactors for simultaneous removal of nitrate and 17β-estradiol: Performance, mechanisms and community assembly potential

The application of bio-manganese (Mn) redox cycling for continuous removal of contaminants provides promise for addressing coexisting contaminants in groundwater, however, the feasibility of constructing Mn redox cycling system (MCS) through community assembly remains to be elucidated. In this study, Mn-reducing strain MFG10 and Mn-oxidizing strain MFQ7 synergistically removed 94.67 % of 17β-estradiol (E2) within 12 h. Analysis of potential variations in Mn oxides suggested that MCS accelerated the production of reactive oxygen species (ROS) and Mn(III), which interacted to promote E2 removal. After continuous operation of the Mn ore-based immobilized bioreactor for 270 days, the experimental group (EG) achieved average removal efficiencies of 89.63 % and 97.57 % for NO3−-N and E2, respectively. High-throughput sequencing results revealed complex symbiotic relationships in EG. Community assembly significantly enhanced the metabolic and physiological activity of the bioreactor, which promoting the expression of core functions including nitrogen metabolism, Mn cycling and organic matter resistance.

RF03 | PMON297 Connecting Fluctuations in Estrogen Production, Release, and Action with Hormone-Dependent Gene Expression in Breast Cancers

Abstract Estrogens are steroid hormones that play a key role in a wide range of physiological and pathological processes. Estrogen receptor-alpha, ERɑ, functions primarily as a nuclear transcription factor (TF) through ligand-dependent activation by 17β-estradiol (E2), the predominant naturally-occurring estrogen. This results in dimerization, DNA binding to cis-regulatory elements called enhancers, and gene regulatory function of ERɑ. In vivo, E2 production and action fluctuates during reproductive cycles and possibly even in a circadian manner. In tissues and cells, E2-regulated gene expression is dynamic, with rapid induction of enhancer formation and target gene expression (or repression), followed by enhancer "decommissioning" and cessation of the gene regulatory effects. The effects of sustained E2 production and signaling, fluctuations in E2 levels, and removal of E2 on estrogen-regulated gene expression are unknown. Classical experiments exploring the gene regulatory effects of E2 involve stimulation of cultured cells throughout the duration of the experiment with a continuous dose of hormone, with the cells harvested at the end of the stimulation period. While this has allowed us to understand the molecular underpinnings of signal-dependent transcription, it has not allowed analysis of physiological fluctuations in estrogen signaling involving periods of stimulation and non-stimulation. In our studies, we are applying a combination of next generation sequencing techniques and fluorescence microscopy to investigate signal-dependent responses to fluctuating E2 levels using ERɑ-positive MCF-7 human breast cancer cells after E2 treatment and removal. Our initial results suggest that different E2 target genes respond differently to E2 withdrawal. Moreover, for some E2 traget genes, sustained E2 treatment may not be required for a complete E2 transcriptional response. With these studies, we hope to connect physiological aspects of E2 production, release, and action with the molecular mechanisms of E2-dependent gene expression - an aspect of our understanding of estrogen signaling that has been lacking. This work is supported by grants from the NIH/NIDDK (DK058110) and CPRIT (RP160319) to W.L.K. Presentation: Saturday, June 11, 2022 1:12 p.m. - 1:17 p.m., Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

Photocatalytic Bi2WO6/pg-C3N4-embedded in polyamide microfiltration membrane with enhanced performance in synergistic adsorption-photocatalysis of 17β-estradiol from water

17β-estradiol (E2) is one of the endocrine disrupting chemicals (EDCs) ubiquitously with significant impacts on ecosystem and organisms even at extremely low concentrations. Photocatalytic membranes, with the combination of photocatalysis and membrane filtration, have great potential to enhance E2 removal. In this work, a photocatalytic membrane was fabricated from the polyamide (PA) microfiltration membrane and visible light responsive Bi2WO6/protonated g-C3N4 (BPG) photocatalyst. The BPG photocatalyst was embedded into calcium alginate hydrogel followed by immobilizing onto PA membrane through vacuum filtration and crosslinking. The transparent calcium alginate hydrogel guaranteed 100% light transmittance which contributed to visible light induced photodegradation. Under static and dynamic conditions, the removal efficiency of E2 reached 99.5% and remained 95.1%, which was mainly owing to the synergistic effects of the adsorption of PA and photodegradation of the BPG nanocomposites. The synergistic interaction was fitted by modified Elovich model, and a strong positive correlation (r = 0.834, rs = 0.965) was confirmed by Pearson’s and Spearman’s correlation coefficient, indicating that adsorption could enhance photocatalysis by concentrating contaminants around the photocatalyst and photocatalysis could promote the adsorption by regenerating adsorption sites. The photocatalytic membrane can be reused, and the removal efficiency of E2 was 96.6% after 5 cycles. This work provided not only a facile fabrication of photocatalytic membrane, but also a deep understanding of the synergistic adsorption-photocatalysis for effective removal of E2.

Sludge from a water treatment plant as an adsorbent of endocrine disruptors

Water Treatment Sludge (WTS) is a solid residue generated in large volumes. This material (in raw or modified form) was never evaluated for endocrine disruptors removal. Thus, the novelty of this work is to evaluate the removal of 17β Estradiol (E2) and 17α Ethinylestradiol (EE2) using adsorbents manufactured from WTS. The WTS underwent heat treatment, resulting in the Physically Modified Sludge (PMS). Then, PMS was chemically activated, giving rise to the sludge activated with phosphoric acid (PAS) or with potassium hydroxide (PHS). The adsorbents were characterized by TGA, ASAP, SEM, FTIR, XRD, XRF, and pH-PZC. The adsorption process was evaluated regarding the adsorbent dosage, kinetic, and isotherms. The modifications imposed on WTS were effective, increasing 1.6 times the surface area and pore volume. The adsorbents presented silica, quartz, and kaolinite in their compositions, and a pH-PZC around 6. The conditions that favor the removal of both endocrine disruptors were: 0.5 g of adsorbent, 100 μg.L−1 of initial concentration, pH of 5.5, and 240 min of stirring. PHS was the most promising adsorbent for E2 (with an adsorption capacity of 10.86 μg.g−1) and PMS for EE2 (removing 6.48 μg.g−1 of contaminant). The equilibrium time and fits kinetic models varied in function of the adsorbate concentration. The interaction between adsorbents-adsorbates occurs by chemisorption at the active sites and similar fits to Langmuir and Freundlich isotherm models were obtained. From the results obtained, a promising application for WTS residues and an alternative for E2 and EE2 removal from the aqueous solution was proposed.

Bioaugmented removal of 17β-estradiol, nitrate and Mn(II) by polypyrrole@corn cob immobilized bioreactor: Performance optimization, mechanism, and microbial community response

The coexistence of nitrate and endocrine substances (EDCs) in groundwater is of global concern. Herein, an efficient and stable polypyrrole@corn cob (PPy@Corn cob) bioreactor immobilized with Zoogloea sp. was designed for the simultaneous removal of 17β-estradiol (E2), nitrate and Mn(II). After 225 days of continuous operation, the optimal operating parameters and enhanced removal mechanism were explored, also the long-term toxicity and microbial communities response mechanisms under E2 stress were comprehensively evaluated. The results showed that the removal efficiencies of E2, nitrate, and Mn(II) were 84.21, 82.96, and 47.91%, respectively, at the optimal operating conditions with hydraulic retention time (HRT) of 8 h, pH of 6.5 and Mn(II) concentration of 20 mg L−1. Further increased of initial E2 (2 and 3 mg L−1) resulted in the inhibiting effect of denitrification and manganese oxidation, but excellent E2 removal efficiencies maintained, which were associated with the formation and continuous accumulation of biomanganese oxides (BMO). Characterization analysis of biological precipitation demonstrated that adsorption and redox conversion on the BMO surface played key roles in the removal of E2. In addition, different levels of E2 exposure are decisive factors in community evolution, and bioaugmented bacterial communities with Zoogloea as the core group can dynamically adapt to E2 stress. This study offers the possibility to better utilize microbial metabolism and to advance opportunities that depend on microbial physiology and material characterization applications.

Phenol and 17β-estradiol removal by Zoogloea sp. MFQ7 and in-situ generated biogenic manganese oxides: Performance, kinetics and mechanism

The pollution of multifarious pollutants such as heavy metal, organic compounds, and nitrate are a hot research topic at present. In this study, the functions of Zoogloea sp. MFQ7 and its biological precipitation formed during bacterial manganese oxidation on the removal of phenol and 17β-estradiol (E2) were investigated. Strain MFQ7, a manganese-oxidizing bacteria, can remove 98.34% of phenol under pH of 7.1, a temperature of 30 ℃ and Mn2+ concentration of 24.34 mg L−1, additionally, the optimum E2 removal by strain MFQ7 was 100.00% at pH of 7.1, temperature of 28 ℃ and Mn2+ concentration of 28.45 mg L−1 by using response surface methodology (RSM) based on Box-Behnken design (BBD) model. The maximum adsorption capacity of bio-precipitation for phenol and E2 was 201.15 mg g−1 and 65.90 mg g−1, respectively. Furthermore, adsorption kinetics and isotherms analysis, XPS, FTIR spectra, Mn(III) trapping experiments elucidated chemical adsorption and Mn(III) oxidation contribute to the removal of phenol and E2 by biogenic manganese oxides. These findings indicated that the adsorption and oxidation of manganese are expected to be one of the effective means to remove these typical organic pollutants containing phenol and E2.

Removal behaviors of aerobic granular sludge on estrogens: Adsorption kinetics and removal mechanism

Aerobic granular sludge (AGS) has the advantages of high biomass and compact structure for withstanding the shocks and toxins. In this study, the removal behaviors of two typical endocrine disrupting chemicals (EDCs), 17β-estradiol (E2) and 17α-ethinylestradiol (EE2), by AGS were investigated. 93.5% of E2 and 84.8% of EE2 were removed at a concentration of 10 μg/L during 120 d operation, with the removal efficiencies of COD, NH4+-N and TP reaching the same level as those in the control group. Batch experimental results showed that the biodegradation was the dominant mechanism of E2 removal, while EE2 was more bio-refractory and mainly removed via adsorption. The adsorption of E2 and EE2 followed heterogeneous multilayer and chemical processes, owing to the active adsorption sites provided by amides, carboxylic groups, hydroxyl groups and polysaccharides on AGS. At the same time, Zoogloea, Sphingomonas, Pseudomonas and Brevundinomas were highly enriched under the pressure of estrogens, which assisted in the stability of AGS reactors by EPS secretion and estrogens degradation.

A Comparative Study on the Biodegradation of 17β-Estradiol by Candida utilis CU-2 and Lactobacillus casei LC-1

The release and fate of estrogens have attracted more and more public attention. Biodegradation is an important method for estrogen removal from the environment. However, few comparative studies concentrated on the degradation of 17β-estradiol (E2) by fungi and bacteria. In this study, the removal efficiencies of E2 by fungi (Candida utilis CU-2) and bacteria (Lactobacillus casei LC-1) were investigated through influencing factors, kinetics, and biodegradation pathways. The results demonstrated that both C. utilis CU-2 and L. casei LC-1 have the same degradation efficiency, and they can effectively degrade E2 (10 μM) with nearly 97% degradation efficiency. However, the biodegradation efficiency of the two strains only reached 20% when E2 was used as a sole carbon source, while it increased to 97% with 1.2 g/L sucrose, glucose, or sodium acetate supply, indicating the occurrence of co-metabolism. In addition, the results indicated that 35°C and 0.6 g/L sucrose favored the degradation. However, the addition of excessive carbon sucrose (10 g/L) significantly inhibited the biodegradation of E2. Besides, the degradation of E2 with ~0–10 g/L sucrose as co-substrate followed the first-order kinetics well. Through intermediate products analysis, 12 degradation products were identified, and they were mainly produced via hydroxylation and methylation, among others, among which C14H22O4 (m/z:[M + H]+ = 255) was detected as the product with the smallest amount of carbon in this study. Based on the detected products and previous studies, five biodegradation pathways were proposed. To our knowledge, there are few reports about the comparisons of E2 removal between fungi and bacteria. Moreover, the results confirmed that the strain CU-2 and the strain LC-1 may have similar degradation characteristics and metabolic mechanisms in the degradation of E2. This study may provide a promising bio-treatment method with low energy consumption for E2 removal from aqueous environments and help in understanding their biodegradation mechanisms.

Study of the Potential of Water Treatment Sludges in the Removal of Emerging Pollutants.

Presently, water quantity and quality problems persist both in developed and developing countries, and concerns have been raised about the presence of emerging pollutants (EPs) in water. The circular economy provides ways of achieving sustainable resource management that can be implemented in the water sector, such as the reuse of drinking water treatment sludges (WTSs). This study evaluated the potential of WTS containing a high concentration of activated carbon for the removal of two EPs: the steroid hormones 17β-estradiol (E2) and 17α-ethinylestradiol (EE2). To this end, WTSs from two Portuguese water treatment plants (WTPs) were characterised and tested for their hormone adsorbance potential. Both WTSs showed a promising adsorption potential for the two hormones studied due to their textural and chemical properties. For WTS1, the final concentration for both hormones was lower than the limit of quantification (LOQ). As for WTS2, the results for E2 removal were similar to WTS1, although for EE2, the removal efficiency was lower (around 50%). The overall results indicate that this method may lead to new ways of using this erstwhile residue as a possible adsorbent material for the removal of several EPs present in wastewaters or other matrixes, and as such contributing to the achievement of Sustainable Development Goals (SDG) targets.