E2 Degradation Research Articles

17 beta-estradiol biodegradation by anaerobic granular sludge: Effect of iron sources

Steroid estrogens, as typical endocrine disrupting chemicals (EDCs), have raised an increasing concern due to their endocrine disrupting effects on aquatic animals and potential hazards on human health. Batch experiments were conducted to study 17 beta-estradiol (E2) removal and Estradiol Equivalent Quantity (EEQ) elimination by anaerobic granular sludge (AnGS) combined with different valence iron sources. Results showed that E2 was effectively biodegraded and transformed into E1 by AnGS. The addition of different valence iron sources all promoted E2 degradation, reduced E2 Equivalent Quotient (EEQ) concentration, and increased methane production in the batch experiments. The enhancement effect of zero-valent iron (ZVI) on E2 removal and EEQ elimination was stronger than that of Fe2+ and Fe3+ in our experiments. The enhancement effect proportion of ZVI corrosion, Fe2+, and Fe3+ in the process of E2 degradation by AnGS combined with ZVI were 42.26%, 40.21% and 17.53%, respectively.

Removal of 17β-Estradiol Using Persulfate Synergistically Activated Using Heat and Ultraviolet Light

Among all female sex hormones, 17β-estradiol (E2) has been most often detected in discharge water from animal farms. The objectives of this study were to evaluate the performance of UV/heat-activated persulfate to degrade E2 and the technical feasibility to use this system for treating real wastewater. As an individual persulfate (PS) homogeneous activator, UV-activated PS removed E2 better than using low heat (40 °C) and solar irradiation to activate PS. When both UV and heat (25–65 °C) were used to activate PS, the Arrhenius equation represented well the observed rate constant, with activation energy of 118.07 kJ mol−1. Inorganic ion concentrations increased the degradation rate. These ions included Cl− (3500 mg L−1), which increased rates by 18.1%, HCO3− (250 mg L−1) by 4.6%, and NO3− (5 mg L−1) by 7.9%. However, lesser impacts on degradation kinetics were observed at higher concentrations for all constituents due to SO4·− scavenging by the formed radicals such as Cl2·−, Cl·, HCO3·, CO3·−, and NO3·. The E2 degradation observed rate constant (kobs) was highest at pH 3. Although both synthetic wastewater and real wastewater showed inhibitory effects due to UV blocking from turbidity and the existence of the –COOH and –OH functional groups that acted as radical scavengers, E2 degradation was still observed. The overall results provided proof-of-concept that UV/heat-activated PS can be applied to treat E2 in wastewater containing a high organic content and can minimize the chemical and operating costs, as solar irradiation provides the heating source.

Advanced oxidative processes in the degradation of 17β-estradiol present on surface waters: kinetics, byproducts and ecotoxicity.

Endocrine disruptors represent risks to aquatic ecosystem and humans, and are commonly detected in surface water. Photochemical treatments can be used to remove 17β-estradiol (E2), but few studies have analyzed the kinetics, intermediates, and 17β-estradiol degradation pathways in natural matrices. In this study, the photochemical behavior of E2 under ultraviolet irradiation (UVC, 254nm) associated with oxidants (H2O2 or O3) or photocatalyst (TiO2) was investigated to evaluate the degradation potential and the transformation pathway in a natural surface water matrix. Additionally, computational modeling analyses with Ecological Structure Activity Relationships (ECOSAR) software were performed to predict the toxicity from the E2 and its transformation byproducts. E2 degradation kinetics showed adjusted to the pseudo-first-order kinetic model, being kUV/O3 > kUV/TiO2 > kUV/H2O2 > kUV. Eight transformation byproducts were identified by liquid chromatography with time-of-flight mass spectrometry (HPLC/TOF-MS) in natural surface water samples. These byproducts formed as the result of opening the aromatic ring and adding the hydroxyl radical. The E2 degradation pathway was proposed based on the byproducts identified in this study and in previous studies, suggesting the formation of aliphatic and hydroxylated byproducts. E2 treatment presented both very toxic and not harmful byproducts.

Isolation and characterization of a new highly effective 17β-estradiol-degrading Gordonia sp. strain R9

In this report, Gordonia sp. strain R9 isolated from an enrichment culture of chicken leachate was confirmed to degrade 17β-estradiol (E2), which can also use other estrogens (estrone, estriol, and 17α-ethynylestradiol) and testosterone as sole carbon and energy sources. Optimization of growth conditions showed that Gordonia sp. strain R9 can tolerate a very wide range of temperature (4-40°C) and pH (1.0-11.0), and is sensitive to antibiotics including kanamycin, ampicillin, chloramphenicol, and carbenicillin. Optimal culture conditions for E2 degradation were 30°C and pH 7.0 with almost 100% degradation of E2 concentrations ranging from 50 µg/L to 5mg/L within 24h. The E2 intermediates so generated included estrone (E1), estratriol (E3), (3Z)-3-(3-hydroxy-3a-methyl-7-oxododecahydro-6H-cyclopenta[a]naphthalen-6-ylidene) propanoic acid and 3-hydroxy-3a-methyl-7-oxododecahydro-1H-cyclopenta[a]naphthalene-6-carboxylic acid. These results indicate that the highly effective E2-degradative ability of Gordonia sp. strain R9 merits further investigation as a candidate for large-scale estrogen biodegradation.

Degradation of 17β-estradiol by Novosphingobium sp. ES2-1 in aqueous solution contaminated with tetracyclines

17β-estradiol (E2) often coexists with tetracyclines (TCs) in wastewater lagoons at intensive breeding farms, threatening the quality of surrounding water bodies. Microbial degradation is vital in E2 removal, but it is unclear how TCs affect E2 biodegradation. This primary study investigated the mechanisms of E2 degradation by Novosphingobium sp. ES2-1 in the presence of TCs and assessed the removal efficiency of E2 by strain ES2-1 in natural waters containing TCs. E2 biodegradation was unaffected at TCs concentrations below 0.1 mg L−1 yet significantly inhibited at TCs above 10 mg L−1. As elevation of TCs, E2 biodegradation rate constant decreased, and the biodegradation kinetics equation gradually deviated from the pseudo-first-order dynamics model. Importantly, the presence of TCs, especially at high-level concentrations, significantly hindered E2 ring-opening process but promoted the condensation of some phenolic ring-opening products with NH3, thereby increasing the abundance of pyridine derivatives, which were difficult to decompose over time. Additionally, strain ES2-1 could remove 52.1–100% of nature estrogens in TCs-contaminated natural waters within 7 d. Results revealed the mechanisms of TCs in E2 biodegradation and the performance of a functional strain in estrogen removal in realistic TCs-contaminated aqueous solution.

The promotion effect of phenolic acid compound on the photo-removal of estrogen from water under simulated sunlight irradiation

Phenol and its derivatives have received a great deal of attention due to their ubiquitous existence in surface water and recognized to be the main constituents in humic substance. However, few relevant studies concerned whether and how phenolic acids affect the fate of endocrine disrupting chemicals in surface water. In this study, the effect of 3, 5-dihydroxybenzoic acid (DHBA) on the phototransformation of 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) under simulated sunlight were systematically investigated. The results showed that DHBA significantly promoted the photolysis of estrogen mainly by producing triplet-excited state and superoxide anion based on density functional theory calculation and quenching experiments for reactive oxygen species (ROS). Interestingly, the intermediates of DHBA could compete with estrogen for reactive species to reduce the enhancing effect on E2 degradation, indicating that the changes on the structure and functional groups of phenolic compounds in photochemical process could further affect the photolysis of contaminants. Photodegradation pathways of E2 in the presence of DHBA were speculated as hydroxylation, oxidation, and coupling reactions. The study provided new insights for better understanding the effects of phenolic compounds on the natural attenuation of emerging organic contaminants in surface water.

Effects of carbon sources on 17 beta-estradiol degradation by Sphingomonas sp. and the analysis of the involved intracellular metabolomics.

17β-estradiol (E2) ubiquitously exists in various water bodies with long-term endocrine-disrupting and carcinogenic impacts on wildlife even at the trace level of ng L-1. However, it remains unclear how easy-to-degrade carbon sources alter E2 biodegradation patterns. In this study, E2 biodegradation by Sphingomonas sp. MCCC 1A06484 was investigated with regard to alternative carbon sources. Results showed that the bacterium preferentially utilized glucose, sodium succinate and sodium acetate over E2. Interestingly, the presence of these preferred nutrients increased the E2 removal efficiency by 20.1%. Furthermore, a positive relation (p < 0.05) between the utilization of total organic carbon (TOC) and E2 was found. Using intracellular metabolomics by UHPLC-QTOF-MS, 11 up-regulated and 35 down-regulated metabolites (variable importance > 1, p < 0.05) were identified in the bacterium when cultivated with E2 under various carbon and nitrogen backgrounds. The E2 exposure contributed to metabolism changes of lipid, nucleotide, carbohydrate, amino acid and membrane transport, which were considered to play roles in the E2 metabolism. The up-regulated phosphatidylcholine might act as an indicator during the bacterial degradation of E2. Generally, this study contributes to an in-depth understanding of E2 biodegradation in complex environments with multiple carbon and nitrogen sources.

Interaction between 17β-estradiol degradation and nitrification in mariculture wastewater by Nitrosomonas europaea and MBBR

This study investigated the relation between 17β-estradiol (E2) degradation and nitrification in synthetic mariculture wastewater by ammonia oxidizing bacterium Nitrosomonas europaea and moving bed biofilm reactor (MBBR). Batch experiments showed that E2 degradation by N. europaea in wastewater followed zero-order reaction kinetics (r2 = 0.944, 4.07 μg/ L h−1) when ammonia presented. Nitrite yield in N. europaea inoculation decreased by 77.8% exposed to 1 mg/L E2. The inhibitory impact on ammonia oxidation was enhanced with increasing E2 dosage from 50 ng/L to 1 mg/L. Notably, E2 as low as 50 ng/L still had significant interference with nitrite production, bacterial density and ammonia monooxygenase (AMO) activity of N. europaea. Still, the following continuous 68-day degradation test revealed that 84.5%–98.7% E2 could be removed by a bench-scale MBBR. Whereas, ammonia removal remarkably decreased from 94.7% ± 2.1% to 85.6% ± 2.1% (p < .05) along with the enhanced E2 removal (from 84.5% ± 2.0% to 98.7% ± 0.4%, p < .05) when inlet E2 increased from 10 μg/L to 1 mg/L, indicating the great role of heterotrophs in E2 degradation. In contrast, nitrite oxidation was not affected upon E2 exposure irrespective of E2 concentrations. In summary, nitrification was effective in removing E2, while E2 interfered with ammoxidation process, but this interference was negligible at the reactor level given the low level of E2 in practical field conditions.

Assessment of environmental applicability of TiO2 coated self-cleaning glass for photocatalytic degradation of estrone, 17β-estradiol and their byproducts

Optimization of photocatalytic degradation of two natural estrogenic compounds, estrone (E1) and 17β-estradiol (17β-E2) in aqueous medium was performed on TiO2 coated Pilkington ActivTM self-cleaning glass as a novel approach to eliminate free nano-TiO2 releasing to the intended environment after treatment. The active glass was characterized by Atomic Force Microscopy (AFM), X-ray diffraction (XRD), and Raman spectroscopy to characterize the TiO2 nanoparticles. The main purposes were mineralization of target compounds in the treated water during the photocatalytic reaction and also to investigate the oxidation by products. Response Surface Methodology (RSM) has been applied to optimize the photocatalytic degradation by changing time, pH, and light intensity as effective factors. According to the results, time was the more effective parameter. The maximum efficiency degradation was achieved in alkaline media. Due to interactive effects between variable factors, 1 mg/L aqueous solution of E1 and 17β-E2 in water was totally decomposed by TiO2 photocatalyzed reactions under UV-C irradiation of 10.08 W/m2 for 52.49 min at pH 9.42. Results of GC-MS analysis were introduced 17-deoxy Estrone and 2-Hydroxyestradiol as intermediate products for E1 and 17β-E2, respectively. All of the peaks finally disappeared after 170 min. Optimized conditions were applied for real sample of wastewater, presenting 30.40% and 56.84% in the efficiency degradation of E1 and 17β-E2, respectively.

Application of a stable Ag/TiO2 film in the simultaneous photodegradation of hormones

AbstractBACKGROUNDThe natural hormones estrone (E1) and 17β‐estradiol (E2) and the synthetic hormone 17α‐ethynylestradiol (EE2) are excreted daily by humans and may reach water and wastewater treatment plants, which do not efficiently remove these estrogens. The aim of the present study was to evaluate the efficiency and reusability of Ag/TiO2 films as catalysts for simultaneous degradation of the hormones E1, E2 and EE2 in aqueous medium by heterogeneous photocatalysis and the contribution of reactive oxygenated species. The influence of aeration on the system and the effects of estrogen concentration and Ag/TiO2 film area were also evaluated in the photodegradation process.RESULTSThe photocatalytic degradation assays showed efficiency higher than 97% for E2 and EE2 (10 μg L−1) after approximately 3.5 h and above 95% for E1 (100 μg L−1) after 4.5 h. It was observed that hydroxyl radical is the main reactive oxidant species in the photodegradation process, responsible for 87, 86 and 79% degradation of E1, E2 and EE2 respectively.CONCLUSIONThe treatment process applied using the Ag/TiO2 films proved to be very stable and efficient for the simultaneous degradation of the studied hormones up to 305 h of reaction period, obtaining a percentage of degradation above 90%. © 2019 Society of Chemical Industry

Characterization of an efficient estrogen-degrading bacterium Stenotrophomonas maltophilia SJTH1 in saline-, alkaline-, heavy metal-contained environments or solid soil and identification of four 17β-estradiol-oxidizing dehydrogenases

The efficient bioremediation of estrogen contamination in complex environments is of great concern. Here the strain Stenotrophomonas maltophilia SJTH1 was found with great and stable estrogen-degradation efficiency even under stress environments. The strain could utilize 17β-estradiol (E2) as a carbon source and degrade 90% of 10 mg/L E2 in a week; estrone (E1) was the first degrading intermediate of E2. Notably, diverse pH conditions (3.0–11.0) and supplements of 4% salinity, 6.25 mg/L of heavy metal (Cd2+ or Cu2+), or 1 CMC of surfactant (Tween 80/ Triton X-100) had little effect on its cell growth and estrogen degradation. The addition of low concentrations of copper and Tween 80 even promoted its E2 degradation. Bioaugmentation of strain SJTH1 into solid clay soil achieved over 80% removal of E2 contamination (10 mg/kg) within two weeks. Further, the whole genome sequence of S. maltophilia SJTH1 was obtained, and a series of potential genes participating in stress-tolerance and estrogen-degradation were predicted. Four dehydrogenases similar to 17β-hydroxysteroid dehydrogenases (17β-HSDs) were found to be induced by E2, and the four heterogenous-expressed enzymes could oxidize E2 into E1 efficiently. This work could promote bioremediation appliance potential with microorganisms and biodegradation mechanism study of estrogens in complex real environments.

Effect of Biochar on 17β-Estradiol Degradation in Composted Poultry Manure: Residue and Bioassay Analysis

While composting is normally a valid approach to decrease 17β-estradiol (E2) contents of manure prior to land application, E2 residues in compost pose a risk to the environment. Biochar is a useful material in composting due to its microstructure. The study aims to compare the effect of amending poultry manure (PM) with two different biochars at three levels on E2 degradation. The seven treatments consisted of compost with no biochar (control) and compost with 5%, 10%, or 15% wheat stalk biochar (WSB) or rice husk biochar (RHB). The results indicated composting with WSB and RHB reduced E2 extractable contents by 71.0–78.5% and 74.2–88.1%, versus 67.8% without biochar. The abundance of two bacteria capable of E2 degradation: Bacillus licheniformis and Bacillus subtilis, increased significantly (p < 0.05) over control in biochar-amended treatments. Moreover, the estrogenic activity (assessed by proliferative assay of MCF-7 cells) of the compost was diminished by the addition of biochar. Our results suggest that E2 degradation was accelerated by adding RHB, possibly by RHB’s provision of a better microenvironment due to larger surface area and pore volume than WSB. Thus, the addition of 15% RHB is recommended for the treatment of PM compost to enhance E2 degradation.

Degradation of Organic Micropollutants in UV/NH2Cl Advanced Oxidation Process.

Monochloramine (NH2Cl) can be irradiated by UV to create an advanced oxidation condition (i.e., UV/NH2Cl) for the elimination of organic micropollutants (OMPs) from source water. However, information in retrospective studies was scarce on how UV/NH2Cl performance would be affected by the water matrix and OMP molecular structures. In this study, the degradation of five representative OMPs, including triclosan, carbamazepine, sulfamethoxazole, estradiol (E2), and ethinylestradiol (EE2), was examined in different water matrices. All OMPs were rapidly removed by UV/NH2Cl but exhibited different degradation mechanisms. Although •OH, •Cl, and direct photolysis mainly contributed to the overall degradation of OMPs in buffered nanopure water, the contribution of reactive nitrogen species (RNS) generated from the photolysis of NH2Cl was not negligible in the degradation of E2 and EE2. A phenolic group was identified as the moiety reactive toward RNS. Based on quantitative analysis of the impact on OMP degradation from cosolutes (including Cl-, HCO3-, NOM) as well as pH and NH2Cl doses, we developed a kinetic model for the prediction of OMP degradation in complex water matrices. In environmental water matrices, the performance and radical contributions in UV/NH2Cl and UV/H2O2 systems were taken into comparison, which showed faster degradation of OMPs and a more significant contribution of CO3•- in the UV/NH2Cl process.

Catalytic degradation of estrogen by persulfate activated with iron-doped graphitic biochar: Process variables effects and matrix effects

Advanced oxidation processes (AOPs) based on sulfate radicals (SO4∙-) is being actively investigated as an effective technology for aqueous organic pollutants degradation. In this work, a novel iron-doped graphitic biochar (Fe@GBC), which was synthesized by one-step method using biomass-derived biochar as precursor and potassium ferrate (K2FeO4) as activator, was applied to activate persulfate (PS) for the degradation of 17β-estradiol (E2). The characterizations indicated that Fe@GBC was successfully doped with iron particles and possessed a porous graphitic carbon structure. In order to evaluate the applicability of Fe@GBC, the effects of various reaction parameters, such as initial pH, catalyst dosage, PS concentration, as well as the reusability and stability of Fe@GBC were systematically investigated. With the synergistic effect of doped iron particles and porous graphitic carbon structure, Fe@GBC exhibited a high activity for PS activation and great degradation capacity to E2 (almost 100% degradation efficiency within 90 min). Through radical quenching experiments and electron spin resonance (ESR) analysis, it found that both SO4∙- and OH∙ were responsible for the degradation of E2, while SO4∙- played a dominant role. Moreover, Fe@GBC/PS also exhibited good degradation performance in complex water matrices. Overall, the facile one-step synthetic strategy and superior performance make Fe@GBC an alternative catalyst for persulfate activation and aqueous pollutants degradation.

The first case of primary hypertrophic osteoarthropathy with soft tissue giant tumors caused by HPGD loss-of-function mutation.

BackgroundPrimary hypertrophic osteoarthropathy (PHO) is a rare genetic multi-organic disease characterized by digital clubbing, periostosis and pachydermia. Two genes, HPGD and SLCO2A1, which encodes 15-hydroxyprostaglandin dehydrogenase (15-PGDH) and prostaglandin transporter (PGT), respectively, have been reported to be related to PHO. Deficiency of aforementioned two genes leads to failure of prostaglandin E2 (PGE2) degradation and thereby elevated levels of PGE2. PGE2 plays an important role in tumorigenesis. Studies revealed a tumor suppressor activity of 15-PGDH in tumors, such as lung, bladder and breast cancers. However, to date, no HPGD-mutated PHO patients presenting concomitant tumor has been documented. In the present study, we reported the first case of HPGD-mutated PHO patient with soft tissue giant tumors at lower legs and evaluated the efficacy of selective COX-2 inhibitor (etoricoxib) treatment in the patient.MethodsIn this study, we summarized the clinical data, collected the serum and urine samples for biochemical test and analyzed the HPGD gene in our patient.ResultsA common HPGD mutation c.310_311delCT was identified in the patient. In addition to typical clinical features (digital clubbing, periostosis and pachydermia), the patient demonstrated a new clinical manifestation, a giant soft tissue tumor on the left lower leg which has not been reported in HPGD-mutated PHO patient before. After 6-month treatment with etoricoxib, the patient showed decreased PGE2 levels and improved PHO-related symptoms. Though the soft tissue tumor persisted, it seemed to be controlled under the etoricoxib treatment.ConclusionThis finding expanded the clinical spectrum of PHO and provided unique insights into the HPGD-mutated PHO.

Insights into estrogenic activity removal using carbon nanotube electrochemical filter

This study reports the performance of a carbon nanotube (CNT) electrochemical filter applied to 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) degradation and their estrogenic activity removal (calculated in terms of E2 equivalent, EQ-E2). The performance of CNT electrochemical filter was assessed at different applied voltages (0–2.5 V) and aqueous matrices (ultrapure water and urban wastewater), using 37 μM of E2 and EE2, a flow rate of 1.5 mL min−1 and 10 mM of Na2SO4, used as supporting electrolyte. Surface characterization of CNT anodic filters was completed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Cyclic voltammetry (CV) was used to investigate electron transfer mechanisms. The CNT electrochemical filter was successfully applied to E2 and EE2 degradation and removals higher than 95.3% (oxidative fluxes >2.94 ± 0.05 mmol h−1 m−2) were achieved when 2.5 V was applied for both ultrapure water and urban wastewater. CV results indicate that the oxidation in the CNT electrochemical filter is an irreversible process. SEM and XPS results showed evidence of the polymer formation on the CNT surface after 300 min of reaction, which probably reduced the efficiency of the process under low applied voltages. Estrogenic activity was considerably reduced and minimal EQ-E2 levels were observed when 2.5 V was applied. A residual EQ-E2 was observed, likely due to the presence of estrogens, which suggests the non-formation of estrogenic intermediates. At 2.5 V total cell potential, the energy required to remove estrogenic activity was 0.014 ± 0.001 kWh m−3 for ultrapure water and 0.021 ± 0.001 kWh m−3 for post-secondary wastewater. These results suggest a CNT electrochemical filter may have potential to effectively and efficiently remove estrogenic activity and may be a feasible process for wastewater polishing treatment.

Ecotoxicological effects and removal of 17β-estradiol in chlorella algae

17β-estradiol (E2) is a steroid estrogen able to affect the reproduction of aquatic organisms even at extremely low concentrations. The behavior of E2 in the presence of chlorella algae was investigated in laboratory experiments. The results showed that the algae's growth was inhibited by 26% after 7 days of culturing in a 2.0 mg L−1 solution of E2. The 96 h EC50 value of 21.46 mg L−1 reflected moderate toxicity. Even low concentrations of E2 were found to affect total chlorophyll and carotenoid levels after 7 and 10 days and to alter stress-generated enzymatic activity in the algae. The efficiency of chlorella's E2 degradation decreased with the increasing of E2 concentration, but 92% of the E2 can be removed from a 0.5 mg L−1 solution over 10 days. The degradation mechanism was speculated. The microalgae suffered relatively less growth inhibition at low E2 concentrations, and their removal effectiveness was then better. The data help to elucidate the interaction between chlorella algae and E2 in an aquatic environment.

Mycoremediation of 17 β‐Estradiol Using Trichoderma citrinoviride Strain AJAC3 along with Enzyme Studies

Extensive and inappropriate use of steroids in drugs and pharmaceutical products and improper release of steroids into the immediate environment has found to affect soil and water resulting in imbalance of ecosystem. The steroids reach environment due to inaccurate disposal of expired drugs as well as manufacturing disposal from pharmaceutical industries and are urgently required to be removed from the environment. The present study deals with elimination of 17 β‐estradiol (E2) using Trichoderma citrinoviride AJAC3. The fungal isolate could tolerate E2 and degrade 99.6% of the contaminant at concentration of 200 mg L−1. Trichoderma citrinoviride AJAC3 secreted extracellular ligninolytic enzymes which played significant role in degradation of E2. High Performance Liquid Chromatography (HPLC) was used to determine the biodegradation pattern of E2 and confirmed by Gas Chromatography Mass Spectroscopy (GC–MS), Scanning Electron Microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR) analysis. Kinetics study revealed that the degradation pathway followed first‐order kinetic model. The results affirmed that the isolate was able to biodegrade E2 efficiently. © 2019 American Institute of Chemical Engineers Environ Prog, 38:e13142, 2019

Degradation of 17β-estradiol and products by a mixed culture of Rhodococcus equi DSSKP-R-001 and Comamonas testosteroni QYY20150409

In this study, we investigated environmental oestrogen 17β-estradiol (E2) degradation by a mixed culture of Rhodococcus equi DSSKP-R-001(RS) and Comamonas testosteroni QYY20150409(CT). The results demonstrated that the two strains exhibited synergistic E2 degradation activity, showing that multispecies bacterial systems can improve microbial survival and activity. The E2 degradation rate for the mixed culture system was 94% under conditions in which E2 was the sole source of carbon and growth energy, while the degradation rates of the R. equi DSSKP-R-001 and C. testosteroni QYY20150409 single strains were 86% and 76%, respectively. Comparing and analyzing the degradation products of E2, intermediate cross-metabolism products were observed in the culture containing the two bacteria. The metabolic products of benzene were essentially removed during the process of E2 degradation in the mixed culture, which showed stronger degradation ability than cultures of the individual strains. The results from this investigation on the degradation of E2 by individual and mixed bacterial cultures provide a theoretical basis for the microbial remediation of environmental oestrogens.

Biochar enhanced microbial degradation of 17β-estradiol.

Steroid estrogens (SEs), especially 17β-estradiol (E2), can be a serious threat to the health of organisms. The removal of E2 from the natural environment is mainly carried out by microbial degradation partly mediated by biochar, which contains quinone structures. In this study, reed straw biochar samples made at four different heat treatment temperatures (HTTs) were used to mediate E2 microbial degradation by Shewanella oneidensis MR-1. The removal efficiency of E2 (95%) was highest in the presence of HTT - 500 °C biochar under anaerobic conditions after 120 h of microbial degradation. The effect of biochar on promoting microbial degradation was far more superior under anaerobic conditions than under aerobic conditions. The redox-activity and types of surface functional groups of biochar reveal that biochar can accept electrons generated by microorganisms in a timely manner. This mechanism promotes the metabolic process of cells and microbial degradation of E2 (exponential increase). Biochar particles rather than biochar-derived water-soluble organic compounds are responsible for this stimulating effect. These results highlight the impact that biochar has on microbial degradation of trace pollutants in a natural environment.