APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2022
·Vol. 106
·期 7
·2403-2414
·
IF 5.56
Zhao Wenyu,Xie Haisheng,Zhang Xuehong,Wang Zhilong
Abstract Water–oil interface of bacterial cell-stabilized Pickering emulsions is an exceptional habitat for microbial assimilation of both hydrophobic nutrients solubilized in oil phase and hydrophilic ones solubilized in water phase. Crystal substrate inhibition, i.e., decreasing phytosterol degradation with the increase loading of crystal phytosterols, is always observed during microbial transformation of phytosterols into steroid synthons in Mycolicibacterium sp (China Center of Industrial Culture Collection, CICC 21,097) cell-stabilized Pickering emulsions. In the present work, we confirmed that crystal substrate inhibition was attributed to the interaction between M. neoaurum and phytosterol crystals that led to the detachment of bacterial cells from the oil–water interfaces in bacterial cell-stabilized Pickering emulsions. Under the selected operation condition (25 ml BEHP per 40 ml water, 60 g/L glucose, 25 g/L phytosterols), the product androst-4-ene-3, 17-dione (AD) and androsta-1, 4-dien-3, 17-dione (ADD) concentration increased linearly with the progress of microbial transformation and reached almost 6 g/L at the 11 th day. This is a paradigm for microbial transformation of crystal substrates as well as in the presence of other surface active additives (such as chitosan and nonionic surfactants) in bacterial cell-stabilized Pickering emulsions. Key points • Microbial transformation of crystal phytosterols in Pickering emulsions • Crystal substrate inhibition occurring during microbial transformation • Interaction between phytosterol crystals and bacterial cells leading to demulsification
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高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2022
·Vol. 41
·期 4
·476-482
·
IF 3.815
Zhang Jian,Zhu Jie,Hua Zan,Liu Guang-Ming
Soil environment on earth contains a variety of ions, which are expected to play a vital role in the biodegradation of plastics discarded in the environment. In this work, poly(butyleneadipate- co -terephthalate) (PBAT) is employed as a model biodegradable plastic to study the specific ion effects on the enzymatic degradation of polyester plastics. The results show that the specific ion effects on the enzymatic degradation rate of the PBAT films and on the catalytic rate constant for the enzymatic hydrolysis of the ester bonds are strongly dependent on temperature and ionic strength. Both the enzymatic degradation rate and catalytic rate constant decrease following the trends Na + > K + > Ca 2+ and Cl − > SO 4
2− > NO 3
− for cations and anions, respectively, indicating that the ion-specific enzymatic degradation of the PBAT films is closely correlated with the specific ion effects on enzymatic hydrolysis of the ester bonds. Our study shows that the specific ion effects on the enzyme activity can be understood by taking into account the ion-specific cation-anion interaction, ionic dispersion force, salting-out effect and salting-in effect. This study of specific ion effects on the enzymatic hydrolysis of the ester bonds and the resultant enzymatic degradation of the PBAT films would offer us a new clue to develop new biodegradable, environmentally friendly synthetic plastics.
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SN Applied Sciences
·
2020
·Vol. 2
·期 9
·1-10
·
IF 0
Alassod Abeer,Islam Syed Rashedul,Farooq Amjad,Xu Guangbiao
Polypropylene is widely used in oil spillage cleanup due to excellent characteristics. However, polypropylene is not renewable and biodegradable, which is unacceptable to introduce new pollutants while solving environmental disasters. Therefore, there is a high demand to explore a low-cost, environmentally friendly, and renewable technique for the fabrication of porous materials. In this work, lignin was chosen as the second blend in the polymer matrix. Polypropylene and renewable lignin sponges were successfully prepared using simple, inexpensive, controllable, scalable, and an environment-friendly method named thermally induced phase separation (TIPS). The surface morphology of obtained sponges was investigated using FTIR and SEM. FTIR analysis indicated that PP and lignin were physically blended. SEM analysis observed an interconnected porous network that acts as a capture site of oil, and lignin merged into PP. The contact angle of PP, PP5L, PP10L, PP15L, and PP20L was found to be 127.4°, 118.71°, 113.89°, 109.45°, and 107°, respectively. Furthermore, polypropylene/lignin sponges have good adsorption ability toward oils compared to polypropylene itself. The research detected that the highest oil sorption tests exhibited by PP10L sponge, which could absorb 983% of soybean oil, 788% of engine oil, and 550% of lubricating oil in the oil system, with high oil retention more than 90% after 24-h dripping. Besides, the results revealed that temperature has a significant effect on oil absorption. All of these features make polypropylene/lignin blend sponges promising sorbents for the oil spills cleanup, not only for oil recovery but also helps in cleaning the environment.
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JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2017
·Vol. 131
·期 2
·1361-1371
·
IF 1.953
Wu Cheng-jie,You Jin-zong,Wang Xue-jie
The thermal decomposition of famciclovir (FCV) was measured with thermogravimetry, differential scanning calorimetry, and thermogravimetric analysis coupled with Fourier transform infrared spectroscopy. The IR spectra, high-performance liquid chromatography, and liquid chromatography–mass spectrometry of FCV and the residues of its thermal decomposition at various temperatures were determined. The molecular bond orders were calculated using an ab initio method from the GAMESS program of quantum chemistry. The mechanism of thermal decomposition for FCV was discussed. The kinetic parameters for thermal decomposition such as activation energy E
a and the pre-exponential factor A were obtained using the Ozawa method. The prospective lifetime of FCV was estimated using the Dakin equation. The results indicated that the thermal decomposition of FCV is a two-step process. The initial decomposition temperature in either nitrogen or air is about 205 °C. The decomposition of FCV does not go through 2-amino-purine stage, 2-amino-purine, and alkane chain segment both decompose simultaneously during the first stage. For decomposition in nitrogen, the E
a and A for the initial thermal decomposition are 107.8 kJ mol −1 and 2.19 × 10 9 min −1 , respectively. For decomposition in air, the corresponding E
a and A are 96.4 kJ mol −1 and 1.45 × 10 8 min −1 , respectively. The FCV has good thermal stability under routine temperature.
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高影响因子
MICROCHIMICA ACTA
·
2022
·Vol. 189
·期 2
·1-10
·
IF 6.408
Wu Xia,Meng Xufeng,Hou Baoxiu,Sun Zhong,Zhang Yunyi,Li Ming
A smartphone-assisted fluorescence color sensing system for rapid, convenient, and on-site detection of copper ions was developed. The ratiometric fluorescence sensor was fabricated by using silica-coated blue-light-emitting carbon dots and surface-grafted red-light-emitting cadmium-telluride quantum dots. After exposure to Cu 2+ in 20 s, the red fluorescence was quenched obviously, while the blue fluorescence remained unchanged, and the sensor color changes continuously from red to blue under the ultraviolet lamp. The concentration (50–1200 nM) of copper ions could be measured by the fluorescence spectrum (excitation at 360 nm, dual-emission at 441 and 640 nm) with a detection limit of 7.7 nM. The fluorescence colors were converted to digital RGB values to calculate the concentration of copper ions by a smartphone with a detection limit of 9.6 nM. The method was applied to detecting copper ions spiked in real samples with recovery from 97.9 to 108.0% and RSD from 3.8 to 8.9%. Thus, this convenient and practical fluorescence color sensing system presents a new strategy for rapid, sensitive, and on-site determination of copper ions in environmental or biological samples. Graphical abstract
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高影响因子
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2019
·Vol. 35
·期 5
·924-928
·
IF 1.071
Xiang Siyuan,Meng Qingnan,Zhang Kai,Gu Yue,Liu Wendong,Yang Bai
Using dextran as both reductant and stabilizing agent, nanopetals(ZnO-Au NPs) were easily synthesized and possessed a petal-like morphology. The feature structure and size of such ZnO-Au NPs were adjustable by regulating the amount of chloroauric acid(HAuCl 4 ). Moreover, the electrochemical property of the obtained NPs was evaluated by being immobilized on the glassy carbon electrode(GCE), which performed both high sensitivity and stability in dopamine(DA) determinations. Furthermore, the as-prepared ZnO-Au NPs could also detect DA and uric acid(UA) simultaneously in the mixture without interference, indicating good selectivity and showing promising potential in biosensing.
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高影响因子
MICROCHIMICA ACTA
·
2018
·Vol. 185
·期 9
·1-10
·
IF 5.705
Khan Md. Zaved H.,Liu Xiaoqiang,Tang Yunfei,Zhu Jinhua,Hu Weiping,Liu Xiuhua
A glassy carbon electrode (GCE) was modified with poly(L-arginine) (P-Arg), reduced graphene oxide (rGO) and gold nanoparticle (AuNP) to obtain an electrode for simultaneous determination of dopamine (DA), serotonin (5-HT) and L-tryptophan (L-Trp) in the presence of ascorbic acid (AA). The modified GCE was prepared via subsequent ‘layer-by-layer’ deposition using an electrochemical technique. The surface morphology of the modified electrode was studied by scanning electron microscopy, and electrochemical characterizations were carried out via cyclic voltammetry and electrochemical impedance spectroscopy. The modified electrode showed excellent electrocatalytic activity toward DA, 5-HT and L-Trp at pH 7.0. Figures of merit for the differential pulse voltammetric reponse are as follows: (a) Response to DA is linear in two intervals, viz. 1.0–50 nM and 1.0–50 μM DA concentration range, the typical working voltage is 202 mV (vs. Ag/AgCl), and the detection limit is 1 nM (at an S/N ratio of 3). For 5-HT, the respective data are 10 to 500 nM and 1.0 to 10 μM, 381 mV, and 30 nM. For L-Trp, the respective data are 10–70 nM and 10–100 μM, 719 mV, and 0.1 μM. The modified GCE is fairly selective. It was successfully applied to the simultaneous determination of DA, 5-HT, and L-Trp in spiked urine samples, and high recovery rates were found.
Schematic presentation of the voltammetric sensor based on a glassy carbon electrode modified with poly(L-arginine), reduced graphene oxide (rGO) and gold nanoparticle (GCE/P-Arg/ErGO/AuNP) for simultaneous determination of dopamine (DA), serotonin (5-HT) and L-tryptophan (L-Trp).
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高影响因子
MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 2
·1-10
·
IF 5.479
Yang Yong,Cheng Jingli,Wang Biao,Guo Yirong,Dong Xiaowu,Zhao Jinhao
A method is described for simultaneous voltammetric determination of the pesticides triazophos (TRS) and thiacloprid (THD). A glassy carbon electrode (GCE) was modified with a metal-organic framework (type UiO-66-NH 2 ) which has a large specific surface (1018 m 2 ·g −1 ) and contains large amounts of Cd(II) and Pb(II) ions, with adsorption capacities of 230 and 271 mg·g −1 , respectively. The antigen-loaded particles were then bound to antibody, magnetically separated, and analyzed by square wave voltammetry to give signals for Cd(II) and Pb(II) at −0.82 and − 0.56 V (vs. Ag/AgCl) for TRS and THD, respectively. Under optimized conditions, the method has a wide linear range (0.2–750 ng·mL −1 ) and low detection limits (0.07 and 0.1 ng·mL −1 at a S/N of 3 for TRS and THD, respectively). It is perceived that this assay represents a useful tool for simultaneous determination of multiple pesticide residues. The method has a wide scope in that may be extended to monitoring of other small organic pollutants by changing the types of metal ions and by using other antibodies.
Schematic presentation of an amino-modified metal-organic framework (type UiO-66-NH 2 ) loaded with Cd(II) and Pb(II) ions for simultaneous electrochemical immunosensing of triazophos (TRS) and thiacloprid (THD). It is based on the fabrication of antigen (Ab)-immobilized UiO-66-NH 2 -based signal tags (a), and of an antibody (Ab)-immobilized magnetic bead (MB-COOH)-based capture probes (b).
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高影响因子
COLLOID AND POLYMER SCIENCE
·
2013
·Vol. 292
·期 1
·153-161
·
IF 2.161
Liu Jingcheng,Luo Jing,Liu Ren,Jiang Jinqiang,Liu Xiaoya
Photosensitive copolymer P(St- alt -MAn)- co -P(VM- alt -MAn) was synthesized and employed to disperse multi-wall carbon nanotubes (MWCNTs). It was found that copolymer could form micelles in aqueous solution and adsorb onto the surface of MWCNTs to produce micelle-encapsulated MWCNTs (e-MWCNTs) by in situ photo crosslinking after irradiation with ultraviolet light and a stable suspension of e-MWCNTs in aqueous solution was obtained. When deposited onto polyaniline (PANI)-modified glassy carbon electrodes, a thin film of e-MWCNTs composite was obtained and the performance of the e-MWCNTs/PANI electrode toward dopamine was then evaluated. The experimental results suggest that the hybrid film modified electrode exhibits a dramatic electrocatalytic effect on the oxidation of dopamine (DA), as evidenced by a marked enhancement of the current response. A series of CVs was obtained by modified glassy-carbon electrodes with different size of micelles was also researched. The result shows that the peak current increased with the increasing size of micelles. A linear calibration plot was obtained in a wide range of 1.0 × 10 −7 –1.0 × 10 −3 M and the detection limit was 5.0 × 10 −8 M. In addition, the interference from ascorbic acid (AA) was effectively suppressed due to the presence of the negatively charged carboxylate groups of copolymer on the outside of MWCNTs which repels AA anions and provides a transport channel only for DA cations.
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高影响因子
JOURNAL OF APPLIED ELECTROCHEMISTRY
·
2019
·Vol. 49
·期 4
·413-421
·
IF 2.366
Duan Wanyi,Li Aoqi,Chen Yujuan,Zhang Jiahui,Zhuo Kelei
In this work, we prepared reduced graphene oxide-supported PtCo nanospheres (PtCo/rGO) by a facile one-step hydrothermal method with the assistance of l -proline as the shape-directing agent. We systematically investigated the effects of various experimental conditions on the morphology and structure of the as-prepared PtCo/rGO hybrids. Compared with commercial Pt/C (10 wt%) and Pt/rGO catalysts, the as-prepared PtCo/rGO has better catalytic activity and poisoning resistance toward methanol electrooxidation and can be used as a promising catalyst for direct methanol fuel cells. Graphical abstract The rGO-supported PtCo nanosphere hybrids are successfully synthesized by a facile one-pot hydrothermal method with the assistance of l -proline. l -proline acts as shape-controlled agent for synthesizing PtCo/rGO. The as-prepared PtCo/rGO hybrids exhibit a higher electrocatalytic activity and poisoning-resistant ability for methanol oxidation in acidic media.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2021
·Vol. 56
·期 28
·16059-16067
·
IF 4.22
Li Huafeng,Li Jing,Bao Yanan,Li Jianliang,He Chengyu,Wang Hengshan,Zhang Yajing,Tang Huayi,Xu Jiao,Fang Yurui,Liang Shuang,Yang Yiming
All-inorganic halide perovskite nanowires (NWs) are promising materials due to they have broad application prospects in the field of optoelectronics, with mixed-halide perovskite nanowires can change the optoelectronic properties by adjusting the halide ratio. Here, we experimentally investigated the two-process governed anion-exchange reaction in single-crystalline CsPbX 3 micro- and nanowires. The critical parameters affecting the outcome of the reaction are identified as the reaction temperature, reaction time, and precursor concentrations. Upon examining the photoluminescence and morphology of the NWs, high-quality NWs were obtained by optimizing these critical parameters. The bandgap of the NWs can be tuned over the entire visible spectra (430–700 nm). In addition, photodetectors incorporating single NWs were fabricated, which demonstrated excellent responsivity under illumination. Our results expand the validity of liquid-phase anion exchange to the microscale, and lay the basis for liquid-processed optoelectronics and displays.
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高影响因子
Frontiers of Chemical Science and Engineering
·
2021
·Vol. 15
·期 5
·1125-1133
·
IF 4.204
Cui Yan,Zeng Zequan,Zheng Jianfeng,Huang Zhanggen,Yang Jieyang
To realize the utilization of visible light and improve the photocatalytic efficiency of organic pollutant degradation in wastewater, a nitrogen-doped titanium-carbon composite (N-TiO 2 /AC) prepared by sol-gel methods was applied in the photodegradation of phenol assisted by persulfate under visible light irradiation (named N-TiO 2 /AC/PS/VIS). The results show that a synergistic effect exists between visible-light photocatalysis and persulfate activation. Compared with TiO 2 /PS/VIS, the phenol degradation rate was found to be observably improved by 65% in the N-TiO 2 /AC/PS/VIS system. This significant increase in degradation rate was mainly attributed to the following two factors: 1) The N and C doping can change the crystal structure of TiO 2 , which extends the TiO 2 absorption wavelength range to the visible light region. 2) As an electron acceptor, PS can not only prevent electrons and holes from recombining with each other but can also generate strong oxidizing radicals such as ·SO 4 − and ·OH to accelerate the reaction dynamics. The process of phenol degradation was found to be consistent with the Langmuir pseudo-first-order kinetic model with an apparent rate constant k of 1.73 min −1 . The N-TiO 2 /AC/PS/VIS process was proven to be a facile method for pollutant degradation with high pH adaptability, excellent visible-light utilization and good application prospects.
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高影响因子
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