JOURNAL OF MICROBIOLOGICAL METHODS
·
2019
·
IF 1.803
Hai-Feng Hu,Hai-Yan Zhou,Mei-Xin Wang,Yuan-Shan Wang,Ya-Ping Xue,Yu-Guo Zheng
( R )-2-(4-hydroxyphenoxy)propionic acid (( R )-HPOPA) is an important intermediate for the synthesis of optically pure aryloxyphenoxypropionic acid herbicides. Regioselective hydroxylation of ( R )-2-phenoxypropionic acid (( R )-POPA) by microbes is one of the most useful methods for the industrial production of ( R )-HPOPA. In this study, we designed and optimized a rapid throughput assay for screening ( R )-HPOPA producing bacterial/fungal strains which can regioselectively hydroxylate ( R )-POPA. ( R )-HPOPA could react with 4-aminoantipyrine (4-AAP) in the presence of potassium hexacyanoferrate (K 3 [Fe(CN) 6 ]) to form indoxyl antipyrine, an orange-red chromophore, that can easily spectrophotometrically be determined at 550 nm. During the verification of the assay we observed an average recovery rate of between 97.3% and 104.5%. Apart from the rapid throughput, no obvious differences in detection ( R )-HPOPA in the culture broth samples were found between our rapid throughput multiplate assay and a high-performance liquid chromatography method. Our optimized assay method is simple, rapid and accurate with high repeatability. It has the potential for high throughput screening (about 3000–5000 samples/day) of the ( R )-HPOPA producing strains.
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高影响因子
JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
·
2018
·Vol. 33
·期 3
·744-748
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IF 0.524
Xu Renxin,Cheng Shixin,Zhou Jing,Shen Jie,Li Zheng,Tan Xing
A novel epoxy-imide resin based on diglycidyl ether of bisphenol-A and N-(4-hydroxyphenyl) terahydrophthalic anhydrideimide (HTAM) was synthesized. The structural characterization of the epoxy-imide resin was conducted by FT-IR spectra. 4,4’-diaminodiphneylmethane (DDM) was used as a curing agent for the epoxy-imide resin. The thermal properties of the cured resin were evaluated with dynamic mechanical analyses (DMA) and thermogravimetric analysis (TGA). The results showed that the cured resin exhibited a high glass transition temperature ( T g ) of 186 °C when the molar amount of HTAM was 0.04 mol in the resin. The yields of the cured resin at 800 °C raised from 16.45% to 19.41%. The flexural properties were also measured, the flexural strength raised from 79.4 to 95.7 MPa, and the flexural modulus exhibited from 2.6 to 3.0 GPa.
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POLYMER
·
2018
·
IF 3.483
Lala Rukh Sidra,Guofei Chen,Cuiyun Li,Nafeesa Mushtaq,Kai Ma,Xingzhong Fang
Two novel unsymmetric diamine isomers, 6-amino-2-(4-(4-aminophenoxy)phenyl)-1H-benzimidazole (3p) and 6-amino-2-(3-(4-aminophenoxy)phenyl)-1H-benzimidazole (3 m), were synthesized and employed to react with several aromatic dianhydrides to yield two new series of poly (benzimidazole imide)s (PBIPIs), PI-4 (a-e) and PI-5 (c-e) through two-step and one step polymerization method, respectively. The effect of chain isomerism on molecular packing and physical properties of PBIPIs is investigated. Both series exhibited excellent thermal stability ( T 5% = 503–559 °C), high T g values (276–383 °C) and good mechanical properties (tensile strengths of 98–151 MPa and tensile moduli of 3.5–5.2 GPa). The PI-5 (c-e) showed high solubility compared to PI-4 (a-e) series. Such improved solubility attributed to the flexible ether connecting groups with non-coplanarity. Furthermore, controlled molecular weight ( Mw ) polymer PI-5e-PA derived from 3 m, demonstrated good solution and melt processability.
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高影响因子
Catalysis Science & Technology
·
2018
·Vol. 8
·期 10
·2578-2587
·
IF 5.365
Yanzi Wang,Jing Sun,Haohai Zhang,Zhiping Zhao,Wenfang Liu
Coenzyme regeneration is important for the industrial utilization of oxidoreductase. In this work, reduced nicotinamide adenine dinucleotide (NADH) was regenerated under visible light via a photosensitizer and an electron donor. First, several photosensitizers including 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP), zinc porphyrin (ZnTCPP) and eosin Y (EY) with varied concentrations were compared. Next, using TCPP as the photosensitizer, the type and concentration of the electron donor, pH value and concentration of the buffer system for the reaction were optimized. Following that, TCPP was immobilized onto the surface of various supports for screening. Then, the immobilization conditions were optimized and the photocatalytic performance of silica-attached TCPP was studied. Lastly, the effect of a rhodium mediator on NADH regeneration was evaluated. The results show that the optimum concentration of TCPP, ZnTCPP and EY was 2, 1 and 4 mM, respectively, and the highest NADH yield of the TCPP system was 2.37 and 1.47 times those of the ZnTCPP and EY systems. With TCPP as the photosensitizer, triethanolamine was the most efficient electron donor and its appropriate concentration was 5 mM. The optimal pH value and concentration of the phosphate buffer was 7.0 and 0.05 M. Under these conditions, a high NADH yield of 81.5% was achieved after 60 min. For the supports examined, the thiol-containing silica microspheres coated with polydopamine and polyethyleneimine had the highest loading capacity of TCPP (9.15 mg per g-support). Via sensitization, the NADH yield was 9.64% after 90 min and was upgraded to 22.5% with the addition of the rhodium mediator.
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高影响因子
BIORESOURCE TECHNOLOGY
·
2018
·
IF 5.807
Ganggang Chong,Junhua Di,Cuiluan Ma,Dajing Wang,Chu Wang,Lingling Wang,Pengqi Zhang,Jun Zhu,Yucai He
In this study, biomass-hydrolysate was used for enhancing the bioreduction of ethyl 4-chloro-3-oxobutanoate (COBE). Firstly, dilute alkalic salt pretreatment was attempted to pretreat bamboo shoot shell (BSS). It was found that enzymatic in situ hydrolysis of 20–50 g/L BSS pretreated with dilute alkalic salts (0.4% Na 2 CO 3 , 0.032% Na 2 S) at 7.5% sulfidity by autoclaving at 110 °C for 40 min gave sugar yields at 59.9%–73.5%. Moreover, linear relationships were corrected on solid recovery-total delignification-sugar yield. In BSS-hydrolysates, xylose and glucose could promote the reductase activity of recombinant E. coli CCZU-A13. Compared with glucose, hydrolysate could increase the reductase activity by 1.35-folds. Furthermore, the cyclohexane-hydrolysate (10:90, v/v) biphasic media containing ethylene diamine tetraacetic acid (EDTA, 40 mM) and l -glutamine (150 mM) was built for the effective biosynthesis of ethyl ( R )-4-chloro-3-hydroxybutanoate [( R )-CHBE] (94.6% yield) from 500 mM COBE. In conclusion, this strategy has high potential for the effective biosynthesis of ( R )-CHBE (>99% e.e. ).
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高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2018
·Vol. 165
·期 11
·B491
·
IF 3.662
Junjuan Qian,Depeng Zhang,Lirong Liu,Yinhui Yi,Mwenze Nkulu Fiston,Odoom Jibrael Kingsford,Gangbing Zhu
As a novel nanomaterial after graphene, molybdenum disulfide (MoS2) has potential applications in electrochemical sensing and other fields, while the low electric conductivity of MoS2 limits its application significantly. In this paper, carbon spheres (CSs) wrapped with molybdenum disulfide (CSs@MoS2) novel nanostructure was successfully prepared via a green hydrothermal method and then used for firstly electrochemical sensing of 4-aminophenol (4-AP, one toxic pollutant). The morphology and structure of CSs@MoS2 were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy and electrochemical impedance spectroscopy. As an electrochemical sensor, CSs@MoS2 nanohybrids modified electrode exhibits excellent electrochemical sensing performance toward 4-AP analysis owing to the synergetic advantages of MoS2 and CSs. Under the optimized conditions, the detection limit of 4-AP obtained in this work is 3 nM and the linear range is 0.01–18.00 μM.
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高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2018
·
IF 2.21
Xiang Gao,Hao Zhao,Yonggang Liu,Zhenpeng Ren,Cuiping Lin,Jianli Tao,Yunpu Zhai
A facile liquid phase reduction method for the preparation of ternary PdNiP-reduced graphene oxide (PdNiP/RGO) nanocomposites is reported. The PdNiP nanoalloys are well dispersed on RGO without obvious aggregation. Relying on the synergistic electronic effect between Pd, Ni, P and RGO, the PdNiP/RGO nanocomposites exhibit superior catalytic activity toward reduction of 4-nitrophenol (4-NP). The 4-NP can be totally reduced to 4-aminophenol (4-AP) by NaBH 4 over PdNiP/RGO catalyst at room temperature very quickly. The maximum reaction rate constant k obtained with PdNiP loading of 20 wt% (20%PdNiP/RGO) was calculated to be 1.41 min −1 , which is 7.8 times higher than the value of unsupported PdNiP.
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高影响因子
BIOPROCESS AND BIOSYSTEMS ENGINEERING
·
2019
·Vol. 42
·期 10
·1573-1582
·
IF 2.371
Zhou Hai-Yan,Li Yi-Zuo,Jiang Rui,Hu Hai-Feng,Wang Yuan-Shan,Liu Zhi-Qiang,Xue Ya-Ping,Zheng Yu-Guo
R -2-(4-hydroxyphenoxy)propionic acid ( R -HPPA) is a key intermediate of the enantiomerically pure phenoxypropionic acid herbicides. R -HPPA could be biosynthesized through selective introduction of a hydroxyl group (–OH) into the substrate R -2-phenoxypropionic acid ( R -PPA) at C-4 position, facilitated by microorganisms with hydroxylases. In this study, an efficient high-throughput screening method for improved R -HPPA biosynthesis through microbial hydroxylation was developed. As a hydroxylated aromatic product, R -HPPA could be oxidized by oxidant potassium dichromate to form brown-colored quinone-type compound. The concentration of R -HPPA can be quantified according to the absorbance of the colored compound at a suitable wavelength of 570 nm; and the R -HPPA biosynthetic capability of microorganism strains could also be rapidly evaluated. After optimization of the assay conditions, the high-throughput screening method was successfully used in identification of Beauveria bassiana mutants with enhanced R -HPPA biosynthesis capacity. A positive mutant C-7 with high tolerance to 20 g/L R -PPA was rapidly selected from 1920 mutants. The biomass and R -HPPA titer were 12.5- and 38.19-fold higher compared with the original strain at 20 g/L R -PPA. This high-throughput screening method developed in this work could also be a potential tool for screening strains producing other important phenolic compounds.
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高影响因子
Nanomaterials
·
2018
·Vol. 8
·期 12
·963
·
IF 3.504
Wei Liu,Xiaolian Zhu,Chengcheng Xu,Zhao Dai,Zhaohui Meng
A new AuNPs-based thermosensitive nanoreactor (SiO2@PMBA@Au@PNIPAM) was designed and prepared by stabilizing AuNPs in the layer of poly(N,N’-methylenebisacrylamide) (PMBA) and subsequent wrapping with the temperature-sensitive poly(N-isopropylacrylamide) (PNIPAM) layer. The new nanoreactor exhibited high dispersibility and stability in aqueous solution and effectively prevented the aggregation of AuNPs caused by the phase transformation of PNIPAM. The XPS and ATR-FTIR results indicated that AuNPs could be well stabilized by PMBA due to the electron transfer between the N atoms of amide groups in the PMBA and Au atoms of AuNPs. The catalytic activity and thermoresponsive property of the new nanoreactor were invested by the reduction of the environmental pollutant, 4-nitrophenol (4-NP), with NaBH4as a reductant. It exhibited a higher catalytic activity at 20 °C and 30 °C (below LCST of PNIPAM), but an inhibited catalytic activity at 40 °C (above LCST of PNIPAM). The PNIPAM layer played a switching role in controlling the catalytic rate by altering the reaction temperature. In addition, this nanoreactor showed an easily recyclable property due to the existence of a silica core and also preserved a rather high catalytic efficiency after 16 times of recycling.Keywords:nanoreactor;distillation precipitation polymerization;catalytic reduction;thermosensitive;AuNPs
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ACS Applied Nano Materials
·
2018
·
IF 0
Xinrui Jiang,Bo Han,Chenggang Zhou,Kaisheng Xia,Qiang Gao,Jinping Wu
Hexagonal boron nitride (h-BN) with a unique 2D architecture is a promising support for catalyst due to its large surface area, high thermal stability, and chemical inertness. However, the weak interaction between h-BN and active metal particles would lead to unexpected agglomeration or loss of active components. In this work, an oxygen-rich mesoporous boron nitride (BNO) support was synthesized by a two-step calcining process, on which Cu nanoparticles were dispersed via a typical adsorption–reduction procedure. The reduction of p-nitrophenol (4-NP) was successively carried out as a model reaction to determine the catalytic performance of the Cu/BNO catalyst. Excellent catalytic activity of 4-NP reduction was implemented with a reaction rate constant of 0.692 min–1, which is maintained almost intact within five cycles. First-principles calculations suggest that the superior durability of Cu/BNO is largely attributed to the weakened conjugation effect of BNO upon O doping, which strengthens the interactions between Cu nanoparticles and BNO supports. Moreover, the doping O atom would significantly enrich the electron density of Cu, which is responsible for the superior activity toward 4-NP reduction.
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ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Lijian Huang,Song Wei,Daocheng Pan
Large-grained Cu2ZnSn(S,Se)4 (CZTSSe) absorber layers are highly desirable for high-performance CZTSSe thin film solar cells. However, solution-deposited CZTSSe thin films usually consist of a large-grained top layer and a smaller-grained bottom layer. In this work, we adopt a phase-separation strategy to promote the crystal growth of the CZTSSe thin film. By choosing ZnCl2, SnCl2, CuCl (instead of CuCl2), and thiourea as the starting materials, a Cu2S/SnS/ZnS hybrid precursor thin film can be prepared, the composition of which has been testified by X-ray diffraction, X-ray photoelectron spectroscopy, Raman, and scanning electron microscopy-energy-dispersive spectrometry characterization. Owing to the volume expansion caused by Se incorporation and the high migration abilities of Cu(I) and Sn(II) ions during selenization, large-grained and compact CZTSSe films with a thickness up to 5 μm can be obtained. The corresponding thin film solar cell devices have achieved active power conversion efficiencies above 10% (8.78% for total area), much higher than those of CuCl2-based CZTSSe devices in our lab.
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高影响因子
NEW JOURNAL OF CHEMISTRY
·
2014
·Vol. 39
·期 1
·639-649
·
IF 3.159
Ying Wu,Kaiqiang Liu,Xiangli Chen,Yongping Chen,Shaofei Zhang,Junxia Peng,Yu Fang
A calix[4]arene-based dimeric-cholesteryl derivative with naphthalene in the linkers (C2N2C) was designed and synthesized. The gelation behaviors of the compound in 36 liquids were evaluated. It was demonstrated that C2N2C could gel 16 of the liquids tested, which include both polar and apolar liquids. SEM and AFM studies revealed that the morphologies of the gel networks are dependent on the concentrations of C2N2C and the nature of the liquids under study. Importantly, rheological studies revealed that the gel of the compound in benzene possesses sensitive, fast and fully reversible thixotropic property. More importantly, the Tgel of the C2N2C/benzene gel could be at least more than 60 degrees higher than the boiling point of benzene when the gelator concentration is greater than 6% (w/v), a result never reported before. CD measurements revealed the chiral nature of the assemblies of the gel networks. Further investigation by AFM measurements confirmed the right-hand helical structures of the gel networks of C2N2C/benzene gel. As anticipated, hydrogen bonding and π–π stacking are the two main driving forces for the formation of the gels.
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