ACS Synthetic Biology
·
2022
·
IF 5.249
Jiawei Li,Mario Roque Huanca Nina,Xiaoyan Zhang,Yunpeng Bai
Poly(ethylene terephthalate) (PET) and phthalate esters (PAEs) are used extensively as plastics and plasticizers. Enzymatic degradation of PET and PAEs has drawn great attention in recent years; however, evolution of PET- and PAE-degrading enzymes is still a big challenge, partly because of the lack of an effective screening method to detect phthalic acid (PA) and terephthalic acid (TPA), which are the main hydrolysis products of PAEs and PET. Here, by directed evolution of a promiscuous transcription factor, XylS from Pseudomonas putida, we created two novel variants, XylS-K38R-L224Q and XylS-W88C-L224Q, that are able to bind PA and TPA and activate the downstream expression of a fluorescent reporter protein. Based on these elements, whole-cell biosensors were constructed, which enabled the fluorimetric detection of as little as 10 μM PA or TPA. A PAE hydrolase, GoEst15, was preliminarily engineered using this new biosensor, yielding a mutant GoEst15-V3 whose activity toward dibutyl phthalate (DBP) and p-nitrophenyl butyrate was enhanced 2.0- and 2.5-fold, respectively. It was shown that 96.5% DBP (5 mM) was degraded by GoEst15-V3 in 60 min, while the wild-type enzyme degraded only 55% DBP. This study provides an effective screening tool for directed evolution of PAE-/PET-degrading enzymes.
研究领域:
生物技术
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环境工程
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生物化学
✓ 已验证
DOI
PubMed
高影响因子
POLYMER DEGRADATION AND STABILITY
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2012
·
IF 2.769
Jing Gao,Zanfang Jin,Zhiyan Pan
Poly(trimethylene terephthalate) (PTT) was depolymerized in hot compressed water (HCW) using a fused-silica capillary reactor (FSCR) and a batch-type autoclave reactor. The phase behavior of PTT in water during the heating, reaction, and cooling processes was observed in an FSCR with a microscope and recorded by a digital camera. It was found that PTT can dissolve in water in a temperature range of 240–320 °C and form a homogeneous aqueous solution. The effects of the reaction temperature (240–320 °C) and reaction time (5–60 min) were evaluated in a batch-type autoclave reactor. The main depolymerization products of PTT were terephthalic acid (TPA) and 1,3-propanediol (1,3-PDO), which were identified by liquid chromatography mass spectrometry , Fourier-transform infrared spectroscopy, gas chromatography mass spectrometry , Raman spectroscopy , and quantified by high-performance liquid chromatography as well as gas chromatography . Additionally, it was found that 1,3-PDO was converted to 1,5-dioxocane partly in the presence of TPA. Under optimal reaction conditions, i.e. 300 °C, 15 min, with a water/PTT ratio of 8:1 (w/w), complete depolymerization was achieved, and the yields of TPA and 1,3-PDO reached 90.5% and 69.03%, respectively. Based on the results, a reaction mechanism for PTT depolymerization in HCW was proposed.
研究领域:
化学工程
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材料科学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Xiru Chen,Xinyue Gu,Chao Wang,Liuqing Huang,Dingding Wu,Hao Wu,Sijia Liang,Jingyi Ling,Cheng Gu
As a common plasticizer, phthalic acid esters (PAEs) have been widely employed to improve the flexibility and workability of polymetric materials, thus leading to their widespread distribution in soils and wastewater. Moreover, PAEs raised great public concerns due to their endocrine-disrupting effects, which could damage reproductive system and body development at low exposure dose. In the present study, a ferrihydrite-H 2 O 2 -bisulfite ternary system was developed to achieve efficient degradation of dimethyl phthalate (DMP). Our results showed that 86.6 % of total DMP could be removed within 240 min by the ferrihydrite-H 2 O 2 -bisulfite ternary system, in which the respective optimum concentration of ferrihydrite, H 2 O 2 and bisulfite was set as 1.0 g/L, 5.0 mM and 2.0 mM. For comparison, negligible DMP removal was observed in the binary systems of ferrihydrite-H 2 O 2 , ferrihydrite-bisulfite and H 2 O 2 -bisulfite. Hydroxyl radical (•OH) was identified as the dominant reactive species for DMP degradation based on the results of electron paramagnetic resonance (EPR) analysis and free radicals quenching experiments. By complexing with iron species, bisulfite could accelerate the reduction of Fe(III) to Fe(II), thus increasing the generation of •OH by ∼4 times in the heterogeneous ferrihydrite-H 2 O 2 system. Furthermore, ferrihydrite exhibited excellent recyclability without any modification as indicated by the negligible decrease in the catalytic degradation efficiency of DMP. Thus, in addition to efficient degradation of PAEs in wastewater, our study would shed light on the in-situ soil remediation technology on the basis of bisulfite-assisted heterogeneous Fenton-like reactions.
研究领域:
环境科学
·
化学
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产品关联
DOI
高影响因子
JOURNAL OF BIOSCIENCE AND BIOENGINEERING
·
2019
·
IF 2.032
Lin Huang,Di Meng,Qiaopeng Tian,Shaolan Yang,Huaxiang Deng,Zhengbing Guan,Yujie Cai,Xiangru Liao
Recently, residual plasticizer phthalate esters (PAEs) in the different environments pose a serious health threat to humans and mammals. Biodegradation has been considered a promising and eco-friendly way to eliminate PAEs. In this study, a gene ( baces04 ) encoding the novel PAEs hydrolase , carboxylesterase (BaCEs04), was screened from the genome of Bacillus velezensis SYBC H47 via bioinformatics analysis. Then, baces04 was cloned and expressed in Escherichia coli BL21 (DE3). BaCEs04 belonged to the esterase family VI. It contained a conserved domain (Gly 159 -His 160 -Ser 161 -Leu 162 -Gly 163 ) and a typical serine hydrolase catalytic site (Ser 161 -Asp 204 -His 261 ). The characterization of BaCEs04 showed that the activity was optimal at 60°C and pH 7.5. This enzyme also displayed high resistance to metal ions, organic solvents , and detergents. After treatment with BaCEs04 for 5 h, the degradation ratio of four different 1 mM PAEs, including dimethyl phthalate, diethyl phthalate, dipropyl phthalate, and dibutyl phthalate, was 32.4%, 50.5%, 77.9%, and 86.8%, respectively. The degradation products of four PAEs were identified as their corresponding monoalkyl phthalates. This is the first report that family VI esterase displaying PAE-hydrolysis activity. This study also proved that BaCEs04 could be used as an ideal candidate for the application in bioremediation and industry.
研究领域:
环境科学
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微生物学
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生物化学
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生物技术
✓ 已验证
DOI
PubMed
高影响因子
ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
·
2020
·
IF 4.872
Jiarong Qiu,Yueqi Zhang,Yaning Shi,Junwei Jiang,Shenglu Wu,Longxiang Li,Yuting Shao,Zhihong Xin
Phthalate esters have raised public concerns owing to their effects on the environment and human health. We identified a novel phthalate-degrading hydrolase, EstJ6, from a metagenomic library using function-driven screening. Phylogenetic analysis indicated that EstJ6 is a member of family IV esterases. EstJ6 hydrolyzed various dialkyl and monoalkyl phthalate esters, and exhibited high hydrolytic activity (128 U/mg) toward dibutyl phthalate at 40 °C and pH 7.5. EstJ6 hydrolyzed not only common phthalate esters with simple side chains but also diethylhexyl phthalate and monoethylhexyl phthalate, which have complex and long side chains. Site-directed mutagenesis indicated that the catalytic triad residues of EstJ6 consists of Ser146, Glu240, and His270. EstJ6 is therefore a promising biodegradation enzyme, and our study illustrates the advantages of a metagenomic approach in identifying enzyme-coding genes for agricultural, food, and biotechnological applications.
研究领域:
环境科学
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生物技术
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生物化学
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产品关联
DOI
PubMed
高影响因子
BIOCHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 3.7
Yufan Pan,Zixin Qi,Shengping You,Yingtong Gao,Yu Zhou,Nan Jiang,Mengfan Wang,Rongxin Su,Wei Qi
The current society has an increasing demand for poly(ethylene terephthalate) (PET). Due to its high crystallinity and hydrophobicity , PET could be hardly degraded for high-value utilization. Besides, the escalating accumulation of waste PET has also led to significant environmental issues. In this study, a convenient and cost-efficient industrial strategy featuring the integration of glycolysis and enzymatic catalysis has been developed for the selective conversion of PET into terephthalic acid (TPA), which provides a method for colored waste PET degradation. Without the need for complex purifying processes, the products of glycolysis directly initiate the next round of the enzymatic system. Through this system, a total yield of 72.47 % of bis-2-(hydroxyethyl) terephthalate(BHET) and mono-(2-hydroxyethyl) terephthalate(MHET) was produced by glycolysis loading sodium bicarbonate (NaHCO 3 ) catalyst, and the enzyme system almost completely converted a substrate concentration of 100 g/L within 48 h, producing 50.36 g/L TPA. Besides, the product problem of pink color in the air after acidification caused by cobalt ions was solved by resin adsorption. In general, the glycolysis and enzymatic catalysis system in this study has prospects for commercial application due to its value for colored waste PET recycling, which reduces the environmental burden caused by waste PET.
研究领域:
环境科学
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生物化学
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材料科学
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产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2025
·
IF 2.8
Yue Shen,Hui He,Cheng Zhang,Hongyu Zhai,Fan Kang,Zebin Xu,Luyun Han
The recycling of waste polyethylene terephthalate (PET) can be facilitated by processing and utilizing the small molecules depolymerized from waste PET. To address the poor post-curing performance of high internal cross-linking in impact resistance, it is necessary for epoxy resin (EP) to undergo toughening modification and broaden its applicability. In the present study, a method used to prepare monomer production from depolymerization was proposed to depolymerize waste PET through the alcohol-alkali combination. The process parameters were further optimized with pretreatment. As the monomer production from depolymerization, recycled terephthalic acid (rTPA) was treated as a chain extender to obtain high-performance modified epoxy resins. Compared with epoxy resin E51, the mechanical properties of rTPA-modified epoxy resin were significantly enhanced. For instance, when rTPA was introduced in small amounts, the tensile strength increased by 46.7% from 50.5 to 74.1 MPa, the flexural strength improved by 49.9% from 78.9 to 118.3 MPa, and the bond strength increased by 32% to 4.38 MPa. As the rTPA content rose sharply, however, the impact strength soared by 384.3% from 7.1 to 34.5 KJ/m 2 , and the flexural modulus rose by 196.4% from 1039 to 3080 MPa. Meanwhile, the water absorption rate remained at an extremely low level.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
TOXICOLOGY AND APPLIED PHARMACOLOGY
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2024
·
IF 3.3
Li-Lan Liu,Jun-Zhe Yue,Zhen-Yu Lu,Ru-Ya Deng,Can-Can Li,Ye-Na Yu,Wen-Jin Zhou,Min Lin,Hai-Tao Gao,Jiaming Liu,Ling-Zi Xia
Phthalates (PEs), such as di(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP) and butyl benzyl phthalate (BBP) could cause reproductive and developmental toxicities , while human beings are increasingly exposed to them at low-doses. Phytochemical quercetin (Que) is a flavonoid that has estrogenic effect, anti-inflammatory and anti-oxidant effects. This study was conducted to assess the alleviative effect of Que. on male reproductive toxicity induced by the mixture of three commonly used PEs (MPEs) at low-dose in rats, and explore the underlying mechanism. Male rats were treated with MPEs (16 mg/kg/day) and/or Que. (50 mg/kg/d) for 91 days. The results showed that MPEs exposure caused male reproductive injuries, such as decreased serum sex hormones levels, abnormal testicular pathological structure, increased abnormal sperm rate and changed expressions of PIWIL1 and PIWIL2. Furthermore, MPEs also changed the expression of steroidogenic proteins in steroid hormone metabolism, including StAR, CYP11A1 , CYP17A1 , 17β-HSD, CYP19A1 . However, the alterations of these parameters were reversed by Que. MPEs caused male reproductive injuries in rats; Que. inhibited MPEs' male reproductive toxicity, which might relate to the improvement of testosterone biosynthesis.
研究领域:
毒理学
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生殖生物学
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药理学
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产品关联
DOI
PubMed
高影响因子
ENVIRONMENT INTERNATIONAL
·
2025
·
IF 9.7
Yingying Sun,Jie Chen,Wei Wang,Lizhong Zhu
Phthalate esters (PAEs) were ubiquitous in agricultural soils and could be metabolized after being absorbed by crops, posing significant implications for crop yield and quality. We hypothesize that monophthalates (mPAEs), the hydrolyzed products of PAEs, might mimic phytohormone jasmonic acid (JA) to activate the JA signaling pathway, therefore enhancing the defense towards pests and inhibiting the rice plant growth. Taking dibutyl phthalate (DBP) as a representative PAE, our study discovered that DBP exposure significantly induced JA-related outcomes including decreased larval weight (9.58–18.8%), and rice biomass (11.7–34.2%). Under the conditions where the JA content remained unchanged, monobutyl phthalate (MBP), the hydrolyzed product of DBP, triggered the JA signaling pathway, evidenced by significantly upregulated genes encoding coronatine insensitive 1 (COI1) (1.56–1.73 fold), jasmonate ZIM-domain (JAZ) (4.33–7.71 fold), MYC2 transcription factor (2.07–2.87 fold), and promoted phytoalexins production in downstream signaling. MBP conjugated with isoleucine, and the conjugate subsequently mimicked a JA bioactivator (JA-isoleucine conjugate) to occupy the binding site of COI1-JAZ co-receptor protein, thereby initiating the JA signaling pathway. These JA-related outcomes and mechanism were consistently evidenced in rice exposed to other four typical PAEs, and the aliphatic chain length of selected PAEs indicated a negative contribution to these observations. In this study, we discovered a unconventional mechanism through which the transformation metabolites of PAEs elicit pest defense while simultaneously inhibiting rice growth, providing insights into the risk assessment of PAEs on crop yields and quality.
研究领域:
环境科学
·
植物生理学
·
农业科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
BIORESOURCE TECHNOLOGY
·
2024
·
IF 9.7
Yu Zhou,Jiaxing Zhang,Shengping You,Wei Lin,Baoyu Zhang,Mengfan Wang,Rongxin Su,Wei Qi
Eco-friendly enzymatic-recycling has been widely utilized in tackling plastic pollution. However, the limited activity on the polyethylene terephthalate (PET) degradation product mono-hydroxyethyl terephthalate (MHET) leads to the formation of heterogeneous hydrolysis products, resulting in PET downcycling. Herein, by applying a dual-function PET hydrolase Is PETase PA with balanced PET and MHET degradation efficiency, an effective PET hydrolysis process was developed to enhance the terephthalic acid (TPA) product purity. Firstly, the impact of pH on the catalytic activity of Is PETase PA revealed that the pH reduction caused by TPA generation hindered the complete conversion of MHET to TPA. Further investigation of the catalytic mechanism showed that the pH-induced protonation of H208 in the catalytic triad destabilized the interaction between Is PETase PA and MHET. Thus, by introducing pH regulation strategy on the bifunctional Is PETase PA , the single-enzyme process could achieve high-purity TPA recovery (>99 %). Overall, this work ensured the high-quality PET enzymatic-recycling for effectively addressing plastic pollution.
研究领域:
环境科学
·
生物技术
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2018
·Vol. 136
·期 11
·47186
·
IF 1.901
Liyuan Sun,Yajie Zhang,Jinggang Wang,Fei Liu,Zhen Jia,Xiaoqing Liu,Jin Zhu
2,5-furandicarboxylic acid (FDCA), a bio-based monomer, was taken as a sustainable alternative to isophthalic acid (IPA) for the modification of poly(ethylene terephthalate) (PET). Results showed that FDCA was more effective than IPA in terms of reducing the crystallization activity of PET, because FDCA is more rigid and highly polar, which will hinder the PET chain packing during crystallization process. Moreover, modification of PET with FDCA resulted in copolyester with higher glass transition temperature, higher tensile modulus, better optical clarity, and gas barrier property, compared to those of IPA. With the addition of 20 mol % FDCA, the resulted copolyester poly(ethylene 2,5-furandicarboxylate- co -ethylene terephthalate) (PEFT 20) was able to keep high transparency even after being annealed at 110 °C for 40 min. However, when 20 mol % of IPA was added, poly(ethylene isophthalate- co -ethylene terephthalate) (PEIT20) easily turned opaque under the same heat treatment. Therefore, less amount of FDCA was required in order to obtain the PET copolyester with better performance. The result indicated that FDCA had great potential to substitute IPA for the modification of PET from the point of view of industrial application. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47186.
研究领域:
材料科学
·
可持续化学
·
高分子化学
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DOI
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2022
·Vol. 97
·期 7
·1695-1704
·
IF 3.709
Bao Guo,Jidong Liu,Shixiong Tang,Yida Liu,Zenan Tian,Jianhua Lv
BACKGROUND Whether waste polyethylene terephthalate (PET) can be effectively recycled is one of the main challenges of the current environmental problems. The hydrolysis of dimethyl terephthalate (DMT) to terephthalic acid (TPA) over Nb-modified HZSM-5 zeolite was studied. Nb/HZSM-5 zeolites with different loadings were prepared and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, NH 3 -temperature programmed desorption and pyridine adsorption infrared spectroscopy. The effects of different reaction conditions on the conversion of DMT and TPA yield were investigated. RESULTS The yield of TPA strongly depends on the reaction conditions and the loading of Nb. The niobium phase exists in the form of Nb 2 O 5 on the zeolite and interacts with the surface of HZSM-5 to produce the active site of Brønsted acid. The yield of TPA is closely related to the concentration of Brønsted acid sites. On 0.6Nb/HZSM-5 catalyst, the yield of TPA is highest, at about 94%. CONCLUSION Nb/HZSM-5 catalyst has excellent catalytic activity and high stability for DMT hydrolysis. In addition, the product TPA prepared in this study can be directly applied to the current PET production supply chain, providing a promising catalytic route. © 2022 Society of Chemical Industry (SCI).
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）