APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2018
·Vol. 102
·期 14
·6039-6046
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IF 3.34
Tigu Fitsum,Zhang Junli,Liu Guoxia,Cai Zhen,Li Yin
d -Pantothenic acid (vitamin B 5 ) has wide applications in the feed, food, chemical, and pharmaceutical industries. Its biological production routes which employ pantothenate synthetase (PS) as the key enzyme are attractive since they avoid the tedious and time-consuming optical resolution process. However, little data is available on the activity and kinetics of this enzyme, hampering the rational selection of an efficient enzyme for the biological production of d -pantothenic acid. In this study, six phylogenetically distant PS-encoding genes, from Escherichia coli , Corynebacterium glutamicum , Bacillus subtilis , Bacillus thuringiensis , Bacillus cereus , and Enterobacter cloacae , were expressed in E. coli . The PS from C. glutamicum exhibited a specific activity of 205.1 U/mg and a turnover number of 127.6 s -1 , which to our best knowledge are the highest values ever reported. The addition of substrates ( d -pantoic acid and β-alanine) to the E. coli strain harboring this enzyme during the early log phase of fermentation resulted in the production of 97.1 g/L of d -pantothenic acid within 32 h, corresponding to a conversion yield of 99.1% and a productivity of 3.0 g/L/h. To the best of our knowledge, this is the highest productivity reported to date.
研究领域:
生物化学
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微生物学
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工业生物技术
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产品关联
DOI
PubMed
高影响因子
Recent Patents on Nanotechnology
·
2020
·Vol. 14
·期 1
·46-55
·
IF 0.977
Liu Zhi,Zhou Lei,Ruan Fangtao,Wei Anfang,Zhao Jianghui,Feng Quan
Background: Nanofiber’s productivity plagues nanofibrous membranes’ applications in many areas. Herein, we present the needle-disk electrospinning to improve throughput. In this method, multiple high-curvature mentals are used as the spinning electrode. Methods: Three
aspects were investigated: 1) mechanism elucidation of the needle-disk electrospinning; 2) parameter optimization of the needle-disk electrospinning; 3) productivity improvement of the needle-disk electrospinning. Results: Results show that high-curvature electrode evokes high electric
field intensity, making lower voltage supply in spinning process. The needle number, needle length and needle curvature synergistically affect the spinning process and nanofiber morphology. Additionally, higher disk rotation velocity and higher voltage supply can also result in higher nanofiber’s
productivity. Conclusion: Compared with previous patents related to this topic, the needle-disk electrospinning is featured with the merits of high throughput, low voltage supply, controllable spinning process and nanofiber morphology, benefiting the nanofiber practical industrial employment
and further applications of nanofiber-based materials.
研究领域:
材料科学
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纳米技术
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工程学
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DOI
高影响因子
Microsystems & Nanoengineering
·
2023
·Vol. 9
·期 1
·1-13
·
IF 7.9
Huang Biao,Ge Xinjin,Rubinstein Boris Y.,Chen Xianchun,Wang Lu,Xie Huiying,Leshansky Alexander M.,Li Zhenzhen
Micron- and submicron-sized droplets have extensive applications in biomedical diagnosis and drug delivery. Moreover, accurate high-throughput analysis requires a uniform droplet size distribution and high production rates. Although the previously reported microfluidic coflow step-emulsification method can be used to generate highly monodispersed droplets, the droplet diameter ( d ) is constrained by the microchannel height ( b ), \(d\gtrsim 3b\) , while the production rate is limited by the maximum capillary number of the step-emulsification regime, impeding emulsification of highly viscous liquids. In this paper, we report a novel, gas-assisted coflow step-emulsification method, where air serves as the innermost phase of a precursor hollow-core air/oil/water emulsion. Air gradually diffuses out, producing oil droplets. The size of the hollow-core droplets and the ultrathin oil layer thickness both follow the scaling laws of triphasic step-emulsification. The minimal droplet size attains \(d\approx 1.7b\) , inaccessible in standard all-liquid biphasic step-emulsification. The production rate per single channel is an order-of-magnitude higher than that in the standard all-liquid biphasic step-emulsification and is also superior to alternative emulsification methods. Due to low gas viscosity, the method can also be used to generate micron- and submicron-sized droplets of high-viscosity fluids, while the inert nature of the auxiliary gas offers high versatility.
研究领域:
生物医学工程
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化学工程
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产品关联
DOI
PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2023
·
IF 22.1
Chaokai Xu,Shengdong Tan,Yaxin Tang,Shibo Xi,Bingqing Yao,Austin Wade,Binbin Zhao,Shangchen Lu,Yankun Du,Mingjiao Tian,Chi He,Lu Ma,Xingjie Fu,Jiwei Shi,Jiong Lu,Alexander G.R. Howe,Sheng Dai,Guangfu Luo,Qian He
We investigated the industrially important PtSn/Al 2 O 3 catalysts prepared with uniform particle sizes (∼ 1 nm) and varied compositions using molecular complexes of Pt(II) and Sn(II). Our best catalyst, with a Sn:Pt ratio of around 2, exhibited a high initial propylene productivity of about 1.1 mol C 3 H 6 (g catalyst) −1 h −1 . Elaborate electron microscopy studies revealed significant compositional variations in the catalyst, highlighting the practical challenges in achieving or confirming the theoretically predicted optimum Sn:Pt ratio. It is also found that the catalytic activities correlate well with the Pt dispersion, suggesting the structure-insensitive nature of the dehydrogenation reaction applies to these ultrasmall Pt-Sn nanoparticles . The presence of Pt-rich particles in the catalysts did not produce noticeable degradations in the reaction selectivity, indicating a wide composition range for Pt-Sn nanoparticles to be effective at the 1 nm size range. These findings emphasize the importance of detailed analysis of compositional distributions for understanding and optimizing nanoalloys.
研究领域:
催化化学
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材料科学
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DOI
高影响因子
RSC Advances
·
2014
·Vol. 4
·期 79
·42202-42210
·
IF 3.708
Xiao-Ying Qv,Yan-Yun Guo,Jian-Guo Jiang
Bio-energy is arousing the common interest of worldwide researchers to investigate it as a substitute for fossil resources. Compared to other bio-energy sources, algae energy has many advantages. This research was aimed to increase the lipid productivity of Dunaliella tertiolecta, an oleaginous microalgae, by optimizing algal culture medium. Plackett–Burman Design (PBD) was adopted to screen out the critical factors from seven nutritional elements. Box–Behnken design (BBD) was used to seek the optimal nutritional conditions for achieving maximum lipid productivity. Results showed that four nutrients, i.e. NaNO3, NaCl, NaHCO3 and NaH2PO4 2H2O, played a critical role in the accumulation of lipid. GC analysis verified that the four critical nutrients mentioned above had different influences on fatty acid methyl esters, moreover, NaCl had the most prominent effects on fatty acid composition of D. tertiolecta. NaCl 87.69 g L−1, NaNO3 1.77 g L−1, NaH2PO4·2H2O 1.92 g L−1, NaHCO3 5.57 g L−1 were proven to be the optimal culture conditions, under which the lipid productivity in the experiment was 12.576 ± 0.12 mg per L per day, which is approaching the theoretically predicted lipid productivity of 12.925 mg per L per day. The lipid productivity was increased by 31.4% under the optimal culture conditions compared to that under the initial medium composition, indicating that optimization of nutrients could effectively improve the lipid production of D. tertiolecta.
研究领域:
生物能源
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微藻研究
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生物技术
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DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2023
·
IF 7.2
Yuan Li,Xu Zhang,Yanting Tian,Xueying Wu,Lei Wang,Jiping Zhu
The electrochemical performance of Ca 3 Co 4 O 9+δ (CCO) oxygen electrode with La 0.6 Sr 0.4 FeO 3-δ (LSF) interlayer in YSZ-based reversible solid oxide cells (RSOCs) was investigated in present work. Results proved that CCO oxygen electrode with LSF interlayer had a superior stability under alternating anodic and cathodic polarization . Both the polarization resistance and overpotential of the CCO electrode with LSF interlayer were significantly reduced compared to that with Ce 0.9 Gd 0.1 O 1.95 (GDC) interlayer, which confirmed the improvement of the redox reactivity of the oxygen electrode. The maximum power density of Ni-YSZ/YSZ/LSF/CCO fuel cell was 1276 mW cm −2 at 800 °C. An electrolysis current density of 1695 mA cm −2 was achieved at 1.5 V and 50% H 2 O. The hydrogen production rate of the electrolysis cell improved by 2 times than that with the GDC interlayer. Results made clear reliability of LSF as an interlayer in YSZ-based RSOCs.
研究领域:
材料科学
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能源工程
·
电化学
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DOI
高影响因子
ChemCatChem
·
2021
·Vol. 13
·期 14
·3312-3318
·
IF 5.686
Ding Ding,Bing Yan,Yang Wang,An-Hui Lu
Graphical Nanofiber Catalysis : Hexagonal boron nitride has been regarded as a potential inorganic nonmetallic catalyst for the oxidative dehydrogenation of propane. Herein, a novel nanofiber catalyst consisting of hexagonal boron nitride/silica oxide ( h -BN/SiO 2 ) was prepared via electrospinning method, which exhibited remarkable 24.9 g olefins ⋅ g BN −1 ⋅ h −1 productivity of olefins in oxidative dehydrogenation of propane. Fibrous nanomaterials have drawn considerable attention in the field of catalysis due to the promoted utilization of the surface and facilitated mass transfer process. In this study, we prepared one-dimensional nanofiber catalysts consisting of hexagonal boron nitride/silica oxide ( h -BN/SiO 2 ) via electrospinning method. The key is to prepare uniform sols consisting of exfoliated h -BN. The diameters of the nanofiber catalysts can be tuned in the range of 150–300 nm through h -BN loading change. When used in oxidative dehydrogenation of propane (ODHP), the obtained nanofibrous catalysts exhibited a 12.4 % conversion of propane and 85.1 % selectivity towards propylene, with remarkable olefins productivity of 24.9 g olefins ⋅ g BN −1 ⋅ h −1 , which is more than 5 times higher than that of bulk ODHP catalysts reported to date. This study shines light on the specific one-dimensional fibrous structure containing dispersed h -BN as well as a new strategy of preparing more efficient boron-based catalysts in the ODHP process.
研究领域:
催化材料
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能源化学
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产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
·
2025
·
IF 4.7
Yan Shen,Yingnan Dou,Liping Sun,Lihua Huo,Hui Zhao
The rational design of electrocatalysts is of great significance in the production of ammonia (NH3) through a nitrate reduction reaction (NO3–RR). This article proposes a design approach to regulate electron redistribution and intermediate adsorption energy by adjusting the work function of alloy compounds. As an example, the NiCo alloy is successfully electrodeposited on carbon cloth (CC) using deep eutectic solvent (DES) as medium. The results show that the ammonia production rate of the NiCo alloy is as high as 1.55 mmol h–1 cm–2 at −0.38 V vs RHE, with the Faraday efficiency to be 84.94%, and the selectivity 94%. Experimental characterizations combined with density functional theory calculations confirm that alloying is beneficial for reducing the work function of Ni. This in turn adjusts the d-band center of the alloy to approach the Fermi level, changes the rate-determining step during the reduction reaction process, and consequently improves the performance. Eventually, an investigation is conducted on the Zn–NO3– battery fabricated with Ni1Co2/CC. This further exhibits the potential of Ni1Co2/CC within the energy conversion equipment. This study brings fresh design concepts and opportunities to the development of novel electrocatalysts for NO3–RR.
研究领域:
电化学
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材料科学
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产品关联
DOI
PubMed
高影响因子
Materials Today Energy
·
2021
·
IF 7.311
Z. Wang,W. Tian,Z. Dai,P. Wang,Y. Xu,X. Li,L. Wang,H. Wang
Electrochemical synthesis of ammonia has attracted widespread attention because of its mild reaction conditions, low energy consumption, and no greenhouse gas generation, but suffers from low ammonia production rate and Faraday efficiency. Here, sulfur-modified silver telluride nanorods (S–Ag 2 Te NRs) have been synthesized as high-efficiency catalysts for the electrochemical synthesis of ammonia. The sulfur modification would offer higher adsorption energy for nitrogen intermediates and more active sites for the hydrogenation of nitrogen to ammonia. Therefore, the S–Ag 2 Te NRs show excellent electrocatalytic performance with an NH 3 yield of 26.44 μg h −1 mg −1 cat. and Faradaic efficiency of 17.48%, which is much higher than that of Ag 2 Te NRs. This work has opened an exciting sulfur-modified strategy to design effective catalysts with diverse morphologies for electrochemical ammonia synthesis.
研究领域:
电化学
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催化
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材料科学
·
能源转换
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产品关联
DOI
高影响因子
Catalysis Science & Technology
·
2022
·Vol. 12
·期 15
·4893-4902
·
IF 6.177
Keting Feng,Tao Sun,Xiaoyun Hu,Jun Fan,Dongyuan Yang,Enzhou Liu
Photocatalytic H2 evolution is a promising way to obtain green H2 due to its clean and sustainable characteristics. Herein, a series of 0D/2D Co0.85Se/TiO2 heterojunctions were fabricated through a successive two-step hydrothermal strategy. Among them, 15%-Co0.85Se/TiO2 displays the most excellent H2 rate of 2312.5 μmol g−1 h−1, which is 10.3 times and 10.8 times higher than that of TiO2 and Co0.85Se, respectively. And the H2 production rate per electrochemically active surface area of 15%-Co0.85Se/TiO2 is 127.41, which is obviously more than that of TiO2 (14.17) and Co0.85Se (5.39). Based on the core-level alignment method and free radical capture tests, the enhanced activity mainly resulted from the higher electrochemically active surface area and the formation of a p–n heterostructure between TiO2 and Co0.85Se. This research provides a strategy for the development of noble metal-free nanocomposites for efficient photocatalytic H2 production.
研究领域:
材料科学
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化学
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能源科学
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环境科学
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产品关联
DOI
高影响因子
Journal of Physical Chemistry C
·
2021
·
IF 4.126
Hanxue Yan,Wenbo Gao,Qianru Wang,Yeqin Guan,Sheng Feng,Han Wu,Qing Guo,Hujun Cao,Jianping Guo,Ping Chen
Palladium (Pd) has long been known to be inactive for dinitrogen activation and hence has received little attention for ammonia synthesis. Herein, we report that the reactivity of Pd is changed when reacting with lithium hydride (LiH) forming a series of lithium palladium hydrides such as LiPdH0.7 and Li2PdH2 (denoted as [Li–Pd–H]). LiPdH0.7 promotes N2 fixation by LiH forming Li2NH and LiPd, and the subsequent hydrogenation of Li2NH and LiPd leads to ammonia and regeneration of LiH and [Li–Pd–H]. Based on these experimental results, an ammonia loop mediated by a [Li–Pd–H]–LiH and LiPd–Li2NH composite pair is proposed and demonstrated. An ammonia production rate of 693 μmolNH3 g–1 h–1 was achieved at 300 °C and 1 bar, which is ca. 7 times that of the neat LiH/Li2NH pair at 350 °C and 1 bar and 2 times that of the thermocatalytic process catalyzed by Ru/MgO at 300 °C and 10 bar.
研究领域:
化学
·
催化
·
材料科学
✓ 已验证
DOI
高影响因子
Frontiers in Materials
·
2023
·
IF 3.2
Guojie Xu,Mingyi Chen,Yufei Gao,Ying Chen,Zhifeng Luo,Han Wang,Jie Fan,Jie Luo,Weicheng Ou,Jun Zeng,Ziming Zhu,Rouxi Chen
Electrospinning (ES) of ceramic fibers has mostly remained in the research level, which can be because of the hard process and parameters controlling the low rate of production. The yield of fiber production by solution blow spinning (SBS) is exciting but the production process is unstable due to the reverse flow phenomenon. In this paper, we prepared high-performance ceramic fibers by gas-assisted electrospinning (GES), which combined the advantages of ES and SBS. Also, comprehensive numerical and experimental analysis for nanofibers produced using GES are provided. The gas flow characteristics through different parameters' nozzle were investigated numerically using computational fluid dynamics and experimentally in a custom-built gas-assisted electrospinning setup to produce SiO2 nanofibers.
研究领域:
材料科学
·
工程学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）