CHINESE JOURNAL OF CHEMISTRY
·
2021
·Vol. 40
·期 8
·918-924
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IF 6
Jisheng Xu,Chengxiang Shi,Shuguang Zhang,Qiancheng Zheng,Lun Pan,Xiangwen Zhang,Ji-Jun Zou
Comprehensive Summary Non-oxidative ethane dehydrogenation is a promising route to produce ethene. Herein, PtSn supported catalysts were investigated to achieve better ethane dehydrogenation performance by introduction of different Zr promoters, i.e. , framework Zr and ZrO 2 , to mesoporous MCM-41. In-situ XRD, TEM and CO chemisorption show that aggregation of metal particles and phase segregation of Pt 3 Sn to Pt and PtSn 3 at high temperature occur for PtSn/M, leading to bad ethane dehydrogenation activity. Strong interaction between ZrO 2 and PtSn species, as proved by XPS, results in restrained metal particles, which promotes the initial reactivity. However, Pt phase generated on surface is disadvantageous for the desorption of produced ethene as indicated by CO-IR and C 3 H 6 -TPD, and pyridine-IR and NH 3 -TPD indicate strong acidity generated. Both deactivate the catalyst rapidly by deep dehydrogenation and coking. Moderate interaction between PtSn species and Si-O-Zr with much weaker acidity is formed when framework Zr is incorporated into MCM-41, which benefits the dispersion of metal particles, formation of Pt 3 Sn/Pt species and stabilization of metal species from phase segregation. Outstanding initial ethane conversion and ethene selectivity of ca. 99% were achieved for the optimal PtSn/ZrM, which is more coking-tolerant and stable by generating graphitic carbon mainly on support instead of active metals.
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
ACS Catalysis
·
2019
·
IF 12.221
Chuanye Xiong,Sai Chen,Piaoping Yang,Shenjun Zha,Zhi-Jian Zhao,Jinlong Gong
Supported vanadium oxides serve as a substitutional catalyst for both propane nonoxidative dehydrogenation (PDH) and oxidative dehydrogenation (ODH), resulting from their substantial activity, propene selectivity, and regeneration rate. However, the nature of the active sites under reaction conditions is still under debate. This paper describes the structure–performance relationships of supported vanadium oxides at different degrees of polymerization by combined density function theory (DFT) and experimental studies. We found that when we expose the vanadium oxides to the pure propane gas, the reaction process can be divided into two periods: the initial oxidative dehydrogenation (ODH) dominant period and subsequent nonoxidative dehydrogenation (PDH) dominant period. In the ODH dominant period, the vanadium oxides tend to lose the top oxygen (V═O), while in the PDH dominant period, the vanadium oxides are relatively stable. Electronic structure analysis indicates that the oxygen p-band center correlates with the dehydrogenation barrier on the oxygen site, which is useful to predict its dehydrogenation activity.
研究领域:
催化化学
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材料科学
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理论化学
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DOI
高影响因子
LWT-FOOD SCIENCE AND TECHNOLOGY
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2020
·
IF 4.006
Yongfu Li,Bin Shi,Yangbo He,Mingxiu Long,Yueliang Zhao
Gamma irradiation can be performed alone or in combination with other preservatives such as dehydroacetic acid (DHA) and sodium dehydroacetate (DHA-Na) to achieve an enhanced level of food safety. Here, we studied the effect of gamma irradiation on the stability and degradation of DHA and DHA-Na in aqueous solution and pear juice. The degradation rate of DHA and DHA-Na was found to increase with increasing irradiation time and decreasing initial solute concentration in aqueous solution. The degradation rate of DHA-Na was higher than that of DHA under the same irradiation conditions. The degradation process of DHA and DHA-Na followed first-order reaction kinetics. The main radiolytic product of DHA and DHA-Na was identified as heptane-2,4,6-trione by GC-MS/MS, and the possible degradation pathway was proposed. Quantum chemical calculation results further confirmed that DHA-Na was much easier to be degraded than DHA. In addition, radiolytic degradation of DHA-Na happened in pear juice, but with a much lower degradation rate than that in aqueous solution.
研究领域:
食品安全
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化学动力学
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辐射化学
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DOI
高影响因子
Nature Communications
·
2023
·Vol. 14
·期 1
·1-11
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IF 16.6
Chen Sai,Luo Ran,Zhao Zhi-Jian,Pei Chunlei,Xu Yiyi,Lu Zhenpu,Zhao Chengjie,Song Hongbo,Gong Jinlong
Propane dehydrogenation (PDH) is an industrial technology for direct propylene production which has received extensive attention in recent years. Nevertheless, existing non-oxidative dehydrogenation technologies still suffer from the thermodynamic equilibrium limitations and severe coking. Here, we develop the intensified propane dehydrogenation to propylene by the chemical looping engineering on nanoscale core-shell redox catalysts. The core-shell redox catalyst combines dehydrogenation catalyst and solid oxygen carrier at one particle, preferably compose of two to three atomic layer-type vanadia coating ceria nanodomains. The highest 93.5% propylene selectivity is obtained, sustaining 43.6% propylene yield under 300 long-term dehydrogenation-oxidation cycles, which outperforms an analog of industrially relevant K-CrO x /Al 2 O 3 catalysts and exhibits 45% energy savings in the scale-up of chemical looping scheme. Combining in situ spectroscopies, kinetics, and theoretical calculation, an intrinsically dynamic lattice oxygen “donator-acceptor” process is proposed that O 2- generated from the ceria oxygen carrier is boosted to diffuse and transfer to vanadia dehydrogenation sites via a concerted hopping pathway at the interface, stabilizing surface vanadia with moderate oxygen coverage at pseudo steady state for selective dehydrogenation without significant overoxidation or cracking.
研究领域:
催化化学
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材料科学
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能源化学
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DOI
PubMed
高影响因子
Genes
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2024
·Vol. 15
·期 3
·365
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IF 2.8
Tianhao Teng,Zhenghua Zheng,Wenqian Jiao,Na Liu,Ao Wang,Mengjiao Liu,Le Xie,Zujing Yang,Jingjie Hu,Zhenmin Bao
Fatty acid desaturases (Fads), as key enzymes in the biosynthesis of long-chain polyunsaturated fatty acids (LC-PUFAs), catalyze the desaturation between defined carbons of fatty acyl chains and control the degree of unsaturation of fatty acids. In the present study, two Fads genes, designatedMulFadsAandMulFadsB, were identified from the genome of the dwarf surf clamMulinia lateralis(Mollusca, Mactridae), and their spatiotemporal expression was examined. MulFadsA and MulFadsB contained the corresponding conserved functional domains and clustered closely with their respective orthologs from other mollusks. Both genes were expressed in the developmental stages and all tested adult tissues ofM. lateralis, withMulFadsAexhibiting significantly higher expression levels in adult tissues thanMulFadsB. Subsequently, the effects of dietary microalgae onFadsexpressions in the dwarf surf clam were investigated by feeding clams with two types of unialgal diets varying in fatty acid content, i.e.,Chlorella pyrenoidosa(Cp) andPlatymonas helgolandica(Ph). The results show that the expressions ofMulFadswere significantly upregulated among adult tissues in the Cp group compared with those in the Ph group. In addition, we observed the desaturation activity of MulFadsA via heterologous expression in yeasts, revealing Δ5 desaturation activity toward PUFA substrates. Taken together, these results provide a novel perspective onM. lateralisLC-PUFA biosynthesis, expanding our understanding of fatty acid synthesis in marine mollusks.
研究领域:
海洋生物学
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生物化学
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分子生物学
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营养学
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PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2024
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IF 3.8
Xinxing Huang,Yong Xu
As one of the most significant chemicals in the industry, 1,3-butadiene has been widely used in various fields. Recently, butane dehydrogenation (BDH) has emerged as a new frontier for the production of 1,3-butadiene. However, this process is limited by the low selectivity to the desired product since BDH experiences a complicated dehydrogenation process and the products consist of various C1–C4 hydrocarbons. Here, we demonstrate that an In2O3-modified Pt-based catalyst can serve as an effective catalyst for the dehydrogenation of n-butane to 1,3-butadiene. The optimum catalyst exhibits n-butane conversion and 1,3-butadiene selectivity of 45.2 and 21.9%, respectively, at 575 °C. Further experimental results indicate that In2O3 can improve the dispersion of Pt, regulate acidity, and suppress n-butane dehydroisomerization (BDI).
研究领域:
催化化学
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工业化学
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DOI
高影响因子
CATALYSIS LETTERS
·
2025
·Vol. 155
·期 4
·1-10
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IF 2.4
Cao Songshuang,Wu Xiaomei,Ma Baodi,Xu Yi
Aliphatic chiral secondary alcohols are important chiral intermediates widely used in the synthesis of drugs and fine chemicals. The whole cells of recombinant E. coli co-expressing alcohol dehydrogenase and glucose dehydrogenase were used to catalyze the asymmetric reduction of three fatty ketones without the addition of exogenous cofactors. The reaction medium and reaction conditions were systematically studied. As expected, the kinds of co-solvents, the molar ratio of glucose/substrate, temperature, pH and cell amount have important influence on the reaction. Under the optimal condition (glucose at 1.5 times substrate concentration, isopropanol at 2%, PBS (0.1 M, pH 8.0), and 45℃), the cells co-expressing both enzymes efficiently catalyzed the asymmetric reduction of three fatty ketones to the corresponding ( S )-fatty alcohols. The conversion and ee value of the products were both greater than 99% after 8 h reaction at 1 M of substrate concentration, and the space-time yield was between 346 ~ 470 g/(L·d). All the products can be obtained on gram scale. The results indicated that this method has potential application value in the efficient and green synthesis of aliphatic chiral secondary alcohols. Graphical
研究领域:
生物化学
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合成生物学
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高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
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2018
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IF 5.667
Shuyun Zhu,Cuihua Lei,Jing Sun,Xian-En Zhao,Xiao Wang,Xiaolu Yan,Wei Liu,Hua Wang
In the present study, a novel colorimetric sensing platform was constructed for probing the NAD + /NADH-dependent biocatalytic transformations. Manganese dioxide (MnO 2 ) nanosheets as an oxidase-mimicking nanomaterial could directly oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) into oxTMB without the need of H 2 O 2 . Importantly, it was found that NADH could easily trigger the decomposition of MnO 2 nanosheets, causing the decrease of solution absorbance. This is demonstrated by the enzyme catalysis reactions of two dehydrogenase models, ethanol dehydrogenase (ADH) and lactate dehydrogenase (LDH), where NADH is formed and consumed, respectively, in their physiological enzymatic reactions. A MnO 2 -TMB sensing platform was thereby proposed for the analysis of their catalytic reaction substrates including ethanol and pyruvic acid. The detection limits of ethanol and pyruvic acid can reach 5.0 μM and 100 nM, respectively. The developed optical biosensing platform can be used to develop other dehydrogenase-based biosensors followed by monitoring their substrates.
研究领域:
生物化学
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纳米生物学
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分析化学
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DOI
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2020
·
IF 4.192
Tian Li,Guo-Song Liu,Wei Zhou,Min Jiang,Yu-Hong Ren,Xin-Yi Tao,Min Liu,Ming Zhao,Feng-Qing Wang,Bei Gao,Dong-Zhi Wei
Squalene has wide applications in the food and pharmaceutical industries. Engineering microbes to produce squalene is a promising alternative for traditional production approaches. In this study, squalene production was enhanced to 978.24 mg/L through stepwise overexpression of the enzymes that catalyze acetyl-CoA to squalene. Subsequently, to increase the activity of HMG-CoA reductase and alleviate the high dependence on NADPH, the HMG-CoA reductase (NADH-HMGR) from Silicibacter pomeroyi, highly specific for NADH, was introduced, which increased squalene production to 1086.31 mg/L. Native ethanol dehydrogenase ADH2 and acetaldehyde dehydrogenase ADA from Dickeya zeae were further overexpressed, which enhanced the capability to utilize ethanol for squalene synthesis and endowed the engineered strain with greater adaptability to high ethanol concentrations. Finally, a remarkable squalene production of 9472 mg/L was obtained from ethanol via carbon source-controlled fed-batch fermentation. This study will greatly accelerate the process of developing microbial cell factories for squalene production.
研究领域:
生物技术
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代谢工程
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微生物生物技术
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DOI
PubMed
高影响因子
ORGANIC PROCESS RESEARCH & DEVELOPMENT
·
2022
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IF 3.858
Ling He,Wenjie Ye,Youyu Xie,Qinghai Liu,Hualei Wang,Dongzhi Wei
Bioreductions catalyzed by ketoreductases play an important role in the synthesis of chiral alcohols. However, the synthesis of (R)-2-chloro-1-(3,4-difluorophenyl)ethanol (24b), an important chiral intermediate for the synthesis of the anticoagulant ticagrelor, poses significant challenges in terms of high substrate concentration requirements that limit its production. In this study, a novel NADH-dependent, short-chain dehydrogenase, PpKR8, from Paraburkholderia phymatum STM815, exhibited excellent enantioselectivity and high activity for the production of (R)-CFPL (24b) through the reduction of 2-chloro-1-(3,4-difluorophenyl)ethanone (24a). The coexpression of PpKR8 and glucose dehydrogenase from Bacillus subtilis in Escherichia coli allowed up to 300 g/L (1.57 M) CFPO (24a) to be completely converted into 24b with 99.9% enantiomeric excess and a high space–time yield (728 g/(L day)). Substrate specificity assays demonstrated a broad substrate spectrum for PpKR8, which included 35 α/β-ketoesters, aromatic ketones, and heterocyclic ketones. Moreover, three additional optically pure chiral alcohols that are used as important drug intermediates were synthesized at high substrate concentrations (150–330 g/L), demonstrating the excellent industrial potential of PpKR8-mediated bioreductions.
研究领域:
生物化学
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酶工程
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制药工业
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高影响因子
Journal of Biological Research-Thessaloniki
·
2020
·Vol. 27
·期 1
·1-10
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IF 2.121
Cao Yujin,Mu Hui,Guo Jing,Liu Hui,Zhang Rubing,Liu Wei,Xian Mo,Liu Huizhou
Background The fuel ethanol industry has made tremendous progress in the last decades. Ethanol can be obtained by fermentation using a variety of biomass materials as the feedstocks. However, few studies have been conducted on ethanol utilization by microorganisms. The price of petroleum-derived ethanol, easily made by the hydrolysis of ethylene, is even lower than that of bioethanol. If ethanol can be metabolized by microorganisms to produce value-added chemicals, it will open a new door for the utilization of inexpensive ethanol resources.Results We constructed an engineered Escherichia coli strain which could utilize ethanol as the sole carbon source. The alcohol dehydrogenase and aldehyde dehydrogenase from Aspergillus nidulans was introduced into E. coli and the recombinant strain acquired the ability to grow on ethanol. Cell growth continued when ethanol was supplied after glucose starvation and 2.24 g L−1 of ethanol was further consumed during the shake-flasks fermentation process. Then ethanol was further used for the production of mevalonic acid by heterologously expressing its biosynthetic pathway. Deuterium-labeled ethanol-D6 as the feedstock confirmed that mevalonic acid was synthesized from ethanol.Conclusion sThis study demonstrated the possibility of using ethanol as the carbon source by engineered E. coli strains. It can serve as the basis for the construction of more robust strains in the future though the catabolic capacity of ethanol should be further improved.
研究领域:
微生物学
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生物技术
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代谢工程
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DOI
PubMed
高影响因子
Microbial Biotechnology
·
2020
·Vol. 14
·期 2
·444-452
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IF 5.328
Meng-Nan Han,Xu-Ming Wang,Chao-Hong Pei,Chao Zhang,Zhidong Xu,Hong-Lei Zhang,Wei Li
Summary Chiral aromatic alcohols have received much attention due to their widespread use in pharmaceutical industries. In the asymmetric synthesis processes, the excellent performance of alcohol dehydrogenase makes it a good choice for biocatalysts. In this study, a novel and robust medium-chain alcohol dehydrogenase RhADH from Rhodococcus R6 was discovered and used to catalyse the asymmetric reduction of aromatic ketones to chiral aromatic alcohols. The reduction of 2-hydroxyacetophenone (2-HAP) to ( R )-(-)-1-phenyl-1,2-ethanediol (( R )-PED) was chosen as a template to evaluate its catalytic activity. A specific activity of 110 U mg −1 and a 99% purity of e.e . was achieved in the presence of NADH. An efficient bienzyme-coupled catalytic system (RhADH and formate dehydrogenase, CpFDH) was established using a two-phase strategy (dibutyl phthalate and buffer), which highly raised the tolerated substrate concentration (60 g l −1 ). Besides, a broad range of aromatic ketones were enantioselectively reduced to the corresponding chiral alcohols by this enzyme system with highly enantioselectivity. This system is of the potential to be applied at a commercial scale.
研究领域:
生物化学
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生物技术
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药物化学
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PubMed
高影响因子
危险品化学品经营许可证（带存储）