71-50-1Relevant academic research and scientific papers
Oxidative decarboxylation of pyruvate by 1-deoxy-D-xyulose 5-phosphate synthase, a central metabolic enzyme in bacteria
DeColli, Alicia A.,Nemeria, Natalia S.,Majumdar, Ananya,Gerfen, Gary J.,Jordan, Frank,Freel Meyers, Caren L.
, p. 10857 - 10869 (2018)
The underexploited antibacterial target 1-deoxy-D-xyluose 5-phosphate (DXP) synthase catalyzes the thiamin diphosphate (ThDP)-dependent formation of DXP from pyruvate and D-glyc-eraldehyde 3-phosphate (D-GAP). DXP is an essential intermediate in the biosynthesis of ThDP, pyridoxal phosphate, and isoprenoids in many pathogenic bacteria. DXP synthase catalyzes a distinct mechanism in ThDP decarboxylative enzymology in which the first enzyme-bound pre-decarboxylation intermediate, C2α-lactyl-ThDP (LThDP), is stabilized by DXP synthase in the absence of D-GAP, and D-GAP then induces efficient LThDP decarboxylation. Despite the observed LThDP accumulation and lack of evidence for C2α-carbanion formation in the absence of D-GAP, CO2 is released at appreciable levels under these conditions. Here, seeking to resolve these conflicting observations, we show that DXP synthase catalyzes the oxidative decarboxylation of pyruvate under conditions in which LThDP accumulates. O2-dependent LThDP decarboxylation led to one-electron transfer from the C2α-carbanion/enamine to O2, with intermediate ThDP-enamine radical formation, followed by peracetic acid formation en route to acetate. Thus, LThDP formation and decarboxylation and DXP formation were studied under anaerobic conditions. Our results support a model in which O2-dependent LThDP decarboxylation and peracetic acid formation occur in the absence of D-GAP, decreasing the levels of pyruvate and O2 in solution. The relative pyruvate and O2 concentrations then dictate the extent of LThDP accumulation, and its buildup can be observed when [pyruvate] > [O2]. The finding that O2 acts as a structurally distinct trigger of LThDP decarboxylation supports the hypothesis that a mechanism involving small molecule– dependent LThDP decarboxylation equips DXP synthase for diverse, yet uncharacterized cellular functions.
Size-Dependent Activity and Selectivity of Atomic-Level Copper Nanoclusters during CO/CO2 Electroreduction
Duan, Lele,Hu, Junhui,Ji, Yongfei,Long, Baihua,Rong, Weifeng,Wei, Shuting,Xi, Shibo,Zang, Wenjie,Zou, Haiyuan
supporting information, p. 466 - 472 (2020/10/29)
As a favorite descriptor, the size effect of Cu-based catalysts has been regularly utilized for activity and selectivity regulation toward CO2/CO electroreduction reactions (CO2/CORR). However, little progress has been made in regulating the size of Cu nanoclusters at the atomic level. Herein, the size-gradient Cu catalysts from single atoms (SAs) to subnanometric clusters (SCs, 0.5–1 nm) to nanoclusters (NCs, 1–1.5 nm) on graphdiyne matrix are readily prepared via an acetylenic-bond-directed site-trapping approach. Electrocatalytic measurements show a significant size effect in both the activity and selectivity toward CO2/CORR. Increasing the size of Cu nanoclusters will improve catalytic activity and selectivity toward C2+ productions in CORR. A high C2+ conversion rate of 312 mA cm?2 with the Faradaic efficiency of 91.2 % are achieved at ?1.0 V versus reversible hydrogen electrode (RHE) over Cu NCs. The activity/selectivity-size relations provide a clear understanding of mechanisms in the CO2/CORR at the atomic level.
Modulation of aggregation behavior, antimicrobial properties and catalytic activity of piperidinium surfactants by modifying their head group with a polar fragment
Gumerova, Sumbela K.,Kushnazarova, Rushana A.,Kuznetsov, Denis M.,Lenina, Oxana A.,Mirgorodskaya, Alla B.,Nikitin, Eugeny N.,Tyryshkina, Anna A.,Voloshina, Alexandra D.,Zakharova, Lucia Ya.
, (2021/06/21)
To establish the effect of surfactants structure on their functional activity a number of alkyl-N-hydroxyethylpiperidinium bromides with different length of the hydrophobic tail were synthesized and characterized. Aggregation parameters of these surfactan
Operando Investigation of Ag-Decorated Cu2O Nanocube Catalysts with Enhanced CO2 Electroreduction toward Liquid Products
Herzog, Antonia,Bergmann, Arno,Jeon, Hyo Sang,Timoshenko, Janis,Kühl, Stefanie,Rettenmaier, Clara,Lopez Luna, Mauricio,Haase, Felix T.,Roldan Cuenya, Beatriz
supporting information, p. 7426 - 7435 (2021/02/26)
Direct conversion of carbon dioxide into multicarbon liquid fuels by the CO2 electrochemical reduction reaction (CO2RR) can contribute to the decarbonization of the global economy. Here, well-defined Cu2O nanocubes (NCs, 35 nm) uniformly covered with Ag nanoparticles (5 nm) were synthesized. When compared to bare Cu2O NCs, the catalyst with 5 at % Ag on Cu2O NCs displayed a two-fold increase in the Faradaic efficiency for C2+ liquid products (30 % at ?1.0 VRHE), including ethanol, 1-propanol, and acetaldehyde, while formate and hydrogen were suppressed. Operando X-ray absorption spectroscopy revealed the partial reduction of Cu2O during CO2RR, accompanied by a reaction-driven redispersion of Ag on the CuOx NCs. Data from operando surface-enhanced Raman spectroscopy further uncovered significant variations in the CO binding to Cu, which were assigned to Ag?Cu sites formed during CO2RR that appear crucial for the C?C coupling and the enhanced yield of liquid products.
Broadband laser-based mid-IR spectroscopy for analysis of proteins and monitoring of enzyme activity
Schwaighofer, Andreas,Akhgar, Christopher K.,Lendl, Bernhard
, (2021/02/26)
Laser-based infrared (IR) spectroscopy is an emerging key technology for the analysis of solutes and for real-time reaction monitoring in liquids. Larger applicable pathlengths compared to the traditional gold standard Fourier transform IR (FTIR) spectroscopy enable robust measurements of analytes in a strongly absorbing matrix such as water. Recent advancements in laser development also provide large accessible spectral coverage thus overcoming an inherent drawback of laser-based IR spectroscopy. In this work, we benchmark a commercial room temperature operated broadband external cavity-quantum cascade laser (EC-QCL)-IR spectrometer with a spectral coverage of 400 cm?1 against FTIR spectroscopy and showcase its application for measuring the secondary structure of proteins in water, and for monitoring the lipase-catalyzed saponification of triacetin. Regarding the obtained limit of detection (LOD), the laser-based spectrometer compared well to a research-grade FTIR spectrometer employing a liquid nitrogen cooled detector. With respect to a routine FTIR spectrometer equipped with a room temperature operated pyroelectric detector, a 15-fold increase in LOD was obtained in the spectral range of 1600–1700 cm?1. Characteristic spectral features in the amide I and amide II region of three representative proteins with different secondary structures could be measured at concentrations as low as 0.25 mg mL?1. Enzymatic hydrolysis of triacetin by lipase was monitored, demonstrating the advantage of a broad spectral coverage for following complex chemical reactions. The obtained results in combination with the portability and small footprint of the employed spectrometer opens a wide range of future applications in protein analysis and industrial process control, which cannot be readily met by FTIR spectroscopy without recurring to liquid nitrogen cooled detectors.
Hydrogen and chemicals from alcohols through electrochemical reforming by Pd-CeO2/C electrocatalyst
Bellini, Marco,Pagliaro, Maria V.,Marchionni, Andrea,Filippi, Jonathan,Miller, Hamish A.,Bevilacqua, Manuela,Lavacchi, Alessandro,Oberhauser, Werner,Mahmoudian, Jafar,Innocenti, Massimo,Fornasiero, Paolo,Vizza, Francesco
, (2021/01/25)
The development of low-cost and sustainable hydrogen production is of primary importance for a future transition to sustainable energy. In this work, the selective and simultaneous production of pure hydrogen and chemicals from renewable alcohols is achieved using an anion exchange membrane electrolysis cell (electrochemical reforming) employing a nanostructured Pd-CeO2/C anode. The catalyst exhibits high activity for alcohol electrooxidation (e.g. 474 mA cm?2 with EtOH at 60 °C) and the electrolysis cell produces high volumes of hydrogen (1.73 l min?1 m?2) at low electrical energy input (Ecost = 6 kWh kgH2?1 with formate as substrate). A complete analysis of the alcohol oxidation products from several alcohols (methanol, ethanol, 1,2-propandiol, ethylene glycol, glycerol and 1,4-butanediol) shows high selectivity in the formation of valuable chemicals such as acetate from ethanol (100%) and lactate from 1,2-propandiol (84%). Importantly for industrial application, in batch experiments the Pd-CeO2/C catalyst achieves conversion efficiencies above 80% for both formate and methanol, and 95% for ethanol.
Highly Selective Production of Ethylene by the Electroreduction of Carbon Monoxide
Chen, Ruixue,Su, Hai-Yan,Liu, Deyu,Huang, Rui,Meng, Xianguang,Cui, Xiaoju,Tian, Zhong-Qun,Zhang, Dong H.,Deng, Dehui
supporting information, p. 154 - 160 (2019/12/15)
Conversion of carbon monoxide to high value-added ethylene with high selectivity by traditional syngas conversion process is challenging because of the limitation of Anderson-Schulz–Flory distribution. Herein we report a direct electrocatalytic process for highly selective ethylene production from CO reduction with water over Cu catalysts at room temperature and ambient pressure. An unprecedented 52.7 % Faradaic efficiency of ethylene formation is achieved through optimization of cathode structure to facilitate CO diffusion at the surface of the electrode and Cu catalysts to enhance the C?C bond coupling. The highly selective ethylene production is almost without other carbon-based byproducts (e.g. C1–C4 hydrocarbons and CO2) and avoids the drawbacks of the traditional Fischer–Tropsch process that always delivers undesired products. This study provides a new and promising strategy for highly selective production of ethylene from the abundant industrial CO.
Energy- And cost-effective non-sterilized fermentation of 2,3-butanediol by an engineered: Klebsiella pneumoniae OU7 with an anti-microbial contamination system
Guo, Ze-Wang,Ou, Xiao-Yang,Xu, Pei,Gao, Hui-Fang,Zhang, Liao-Yuan,Zong, Min-Hua,Lou, Wen-Yong
, p. 8584 - 8593 (2020/12/31)
Microbial contamination is a serious challenge that needs to be overcome for the successful biosynthesis of 2,3-butanediol (2,3-BD). However, traditional strategies such as antibiotic administration or sterilization are costly, have high energy demands, and may increase the risk of antibiotic resistance. Here, we intend to develop a robust strategy to achieve non-sterilized fermentation of 2,3-BD. Briefly, the robust strain can metabolize unconventional chemicals as essential growth nutrients, and therefore, outcompete contaminant microbes that cannot use unconventional chemicals. To this end, Klebsiella pneumoniae OU7, a robust strain, was confirmed to rapidly exploit urea and phosphite (unconventional chemicals) as the primary sources of nitrogen (N) and phosphorus (P), and withstand deliberate contamination in the possibly contaminated systems. Secondly, metabolic engineering, pathogenicity elimination and adaptive laboratory evolution were successively performed, endowing the best strain with an excellent fermentation performance for safe 2,3-BD production. Finally, 84.53 g L-1 of 2,3-BD was synthesized with a productivity of 1.17 g L-1 h-1 and a yield of 0.38 g g-1 under the non-sterilized system. In summary, our technique reduces labor and energy costs and simplifies the fermentation process because sterilization does not need to be performed. Thus, our work will be beneficial for the sustainable synthesis of 2,3-BD. This journal is
Electroreduction of CO2to Formate on a Copper-Based Electrocatalyst at High Pressures with High Energy Conversion Efficiency
Chiang, Ching-Yu,Dai, Hongjie,Guo, Jinyu,Hung, Wei-Hsuan,Ku, Ching-Shun,Kuang, Yun,Li, Aowen,Li, Jiachen,Meng, Yongtao,Sun, Xiaoming,Tian, Xin,Xu, Mingquan,Zhang, Xiao,Zhou, Wu,Zhu, Guanzhou
supporting information, p. 7276 - 7282 (2020/08/06)
Electrocatalytic CO2 reduction (CO2RR) to valuable fuels is a promising approach to mitigate energy and environmental problems, but controlling the reaction pathways and products remains challenging. Here a novel Cu2O nanoparticle film was synthesized by square-wave (SW) electrochemical redox cycling of high-purity Cu foils. The cathode afforded up to 98percent Faradaic efficiency for electroreduction of CO2 to nearly pure formate under ≥45 atm CO2 in bicarbonate catholytes. When this cathode was paired with a newly developed NiFe hydroxide carbonate anode in KOH/borate anolyte, the resulting two-electrode high-pressure electrolysis cell achieved high energy conversion efficiencies of up to 55.8percent stably for long-term formate production. While the high-pressure conditions drastically increased the solubility of CO2 to enhance CO2 reduction and suppress hydrogen evolution, the (111)-oriented Cu2O film was found to be important to afford nearly 100percent CO2 reduction to formate. The results have implications for CO2 reduction to a single liquid product with high energy conversion efficiency.
Discovery and mechanistic investigation of Pt-catalyzed oxidative homocoupling of benzene with PhI(OAc)2
Abu-Omar, Mahdi M.,Nabavizadeh, S. Masoud,Niroomand Hosseini, Fatemeh,Park, Chan,Wu, Guang
supporting information, p. 2477 - 2486 (2020/03/05)
We present a Pt-catalyzed direct coupling of benzene to biphenyl. This catalytic reaction employs a cyclometalated platinum(ii) complex [PtMe(bhq)(SMe2)] (bhq = benzo[h]quinolate) with PhI(OAc)2 as an oxidant and does not require an acid, a co-catalyst or a solvent. The reaction kinetics and characterization of potential catalytic species are reported. The reaction is first-order in Pt and second-order in benzene, which implicates the second C-H activation step as rate-determining. A Pt(ii)/Pt(iv) catalytic cycle is suggested. The reaction commences by oxidation of the Pt(ii) complex to give the platinum(iv) species [Pt(bhq)(SMe2)(OAc)2](OAc) followed by C-H activation of benzene to afford the intermediate [PtPh(bhq)(SMe2)(OAc)](OAc) concurrently with the release of HOAc. A second benzene molecule reacts similarly to give the diphenyl intermediate [PtPh2(bhq)(SMe2)](OAc). C-C bond forming reductive elimination ensues to regenerate Pt(ii) and complete the catalytic cycle. The proposed mechanism has been examined by DFT computations, which provide support to experimental findings.
