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Multistep conversion of cresols by phenol hydroxylase and 2,3-dihydroxy-biphenyl 1,2-dioxygenase

Shengnan SHI,Fang MA,Tieheng SUN,Ang LI,Jiti ZHOU,Yuanyuan QU

《环境科学与工程前沿（英文）》 2014年 第8卷 第4期   页码 539-546 doi: 10.1007/s11783-013-0616-y

摘要： A multistep conversion system composed of phenol hydroxylase (PH ) and 2,3-dihydroxy-biphenyl 1,2-dioxygenase (BphC ) was used to synthesize methylcatechols and semialdehydes from - and -cresol for the first time. Docking studies displayed by PyMOL predicted that cresols and methylcatechols could be theoretically transformed by this multistep conversion system. High performance liquid chromatography mass spectrometry (HPLC-MS) analysis also indicated that the products formed from multistep conversion were the corresponding 3-methylcatechol, 4-methylcatechol, 2-hydroxy-3-methyl-6-oxohexa-2,4-dienoic acid (2-hydroxy-3-methyl-ODA) and 2-hydroxy-5-methyl-6-oxohexa-2,4-dienoic acid (2-hydroxy-5-methyl-ODA). The optimal cell concentrations of the recombinant strain BL21 (DE3) expressing phenol hydroxylase (PH ) and 2,3-dihydroxy-biphenyl 1,2-dioxygenase (BphC ) and pH for the multistep conversion of - and -cresol were 4.0 (g·L cell dry weight) and pH 8.0, respectively. For the first step conversion, the formation rate of 3-methylcatechol (0.29 μmol·L ·min ·mg cell dry weight) from -cresol was similarly with that of methylcatechols (0.28 μmol·L ·min ·mg cell dry weight) from -cresol by strain PH . For the second step conversion, strain BphC showed higher formation rate (0.83 μmol·L ·min ·mg cell dry weight) for 2-hydroxy-3-methyl-ODA and 2-hydroxy-5-methyl-ODA from -cresol, which was 1.1-fold higher than that for 2-hydroxy-3-methyl-ODA (0.77 μmol·L ·min ·mg cell dry weight) from -cresol. The present study suggested the potential application of the multistep conversion system for the production of chemical synthons and high-value products.

关键词： multistep conversion     cresols     phenol hydroxylase     2     3-dihydroxybiphenyl 1     2-dioxygenase     methylcatechols    

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Microfluidic dual loops reactor for conducting a multistep reaction

Si Hyung Jin, Jae-Hoon Jung, Seong-Geun Jeong, Jongmin Kim, Tae Jung Park, Chang-Soo Lee

《化学科学与工程前沿（英文）》 2018年 第12卷 第2期   页码 239-246 doi: 10.1007/s11705-017-1680-9

摘要： Precise control of each individual reaction that constitutes a multistep reaction must be performed to obtain the desired reaction product efficiently. In this work, we present a microfluidic dual loops reactor that enables multistep reaction by integrating two identical loop reactors. Specifically, reactants A and B are synthesized in the first loop reactor and transferred to the second loop reactor to synthesize with reactant C to form the final product. These individual reactions have nano-liter volumes and are carried out in a stepwise manner in each reactor without any cross-contamination issue. To precisely control the mixing efficiency in each loop reactor, we investigate the operating pressure and the operating frequency on the mixing valves for rotary mixing. This microfluidic dual loops reactor is integrated with several valves to realize the fully automated unit operation of a multistep reaction, such as metering the reactants, rotary mixing, transportation, and collecting the product. For proof of concept, CdSeZn nanoparticles are successfully synthesized in a microfluidic dual loops reactor through a fully automated multistep reaction. Taking all of these features together, this microfluidic dual loops reactor is a general microfluidic screening platform that can synthesize various materials through a multistep reaction.

关键词： microfluidics     multistep reaction     rotary mixing     nanoparticle    

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Hydrogel photocatalysts for efficient energy conversion and environmental treatment

《能源前沿（英文）》 2021年 第15卷 第3期   页码 577-595 doi: 10.1007/s11708-021-0756-x

摘要： Photocatalysts have attracted great research interest owing to their excellent properties and potential for simultaneously addressing challenges related to energy needs and environmental pollution. Photocatalytic particles need to be in contact with their respective media to exhibit efficient photocatalytic performances. However, it is difficult to separate nanometer-sized photocatalytic materials from reaction media later, which may lead to secondary pollution and a poor recycling performance. Hydrogel photocatalysts with a three-dimensional (3D) network structures are promising support materials for photocatalysts based on features such as high specific surface areas and adsorption capacities and good environmental compatibility. In this review, hydrogel photocatalysts are classified into two different categories depending on their elemental composition and recent progresses in the methods for preparing hydrogel photocatalysts are summarized. Moreover, current applications of hydrogel photocatalysts in energy conversion and environmental remediation are reviewed. Furthermore, a comprehensive outlook and highlight future challenges in the development of hydrogel photocatalysts are presented.

关键词： hydrogel     photocatalysts     energy conversion     environmental treatment    

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Biological conversion pathways of sulfate reduction ammonium oxidation in anammox consortia

Zhen Bi, Deqing Wanyan, Xiang Li, Yong Huang

《环境科学与工程前沿（英文）》 2020年 第14卷 第3期 doi: 10.1007/s11783-019-1217-1

摘要： The SRAO phenomena tended to occur only under certain conditions. High amount of biomass and non-anaerobic condition is requirement for SRAO. Anammox bacteria cannot oxidize ammonium with sulfate as electron acceptor. AOB and AnAOB are mainly responsible for ammonium conversion. Heterotrophic sulfate reduction mainly contributed to sulfate conversion. For over two decades, sulfate reduction with ammonium oxidation (SRAO) had been reported from laboratory experiments. SRAO was considered an autotrophic process mediated by anammox bacteria, in which ammonium as electron donor was oxidized by the electron acceptor sulfate. This process had been attributed to observed transformations of nitrogenous and sulfurous compounds in natural environments. Results obtained differed largely for the conversion mole ratios (ammonium/sulfate), and even the intermediate and final products of sulfate reduction. Thus, the hypothesis of biological conversion pathways of ammonium and sulfate in anammox consortia is implausible. In this study, continuous reactor experiments (with working volume of 3.8L) and batch tests were conducted under normal anaerobic (0.2≤DO<0.5 mg/L) / strict anaerobic (DO<0.2 mg/L) conditions with different biomass proportions to verify the SRAO phenomena and identify possible pathways behind substrate conversion. Key findings were that SRAO occurred only in cases of high amounts of inoculant biomass under normal anaerobic condition, while absent under strict anaerobic conditions for same anammox consortia. Mass balance and stoichiometry were checked based on experimental results and the thermodynamics proposed by previous studies were critically discussed. Thus anammox bacteria do not possess the ability to oxidize ammonium with sulfate as electron acceptor and the assumed SRAO could, in fact, be a combination of aerobic ammonium oxidation, anammox and heterotrophic sulfate reduction processes.

关键词： Anammox bacteria     Autotrophic     Biological conversion     Sulfate reducing ammonium oxidation (SRAO)    

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Sustainable conversion regenerated cellulose into cellulose oleate by sonochemistry

《化学科学与工程前沿（英文）》 2023年 第17卷 第8期   页码 1096-1108 doi: 10.1007/s11705-023-2317-9

摘要： Derivatization has great potential for the high-value utilization of cellulose by enhancing its processability and functionality. However, due to the low reactivity of natural cellulose, it remains challenging to rapidly prepare cellulose derivatives with high degrees of substitution. The “cavitation effect” of ultrasound can reduce the particle size and crystalline index of cellulose, which provides a possible method for preparing cellulose derivatives. Herein, a feasible method was proposed for efficiently converting regenerated cellulose to cellulose oleate with the assistance of ultrasonic treatment. By adjusting the reaction conditions including ultrasonic intensity, feeding ratios of oleic acid, reaction time, and reaction solvent, a series of cellulose oleates with degrees of substitution ranging from 0.37 to 1.71 were synthesized. Additionally, the effects of different reaction conditions on the chemical structures, crystalline structures, and thermal behaviors were investigated thoroughly. Cellulose oleates with degrees of substitution exceeding 1.23 exhibited amorphous structures and thermoplasticity with glass transition temperatures at 159.8 to 172.6 °C. This study presented a sustainable and practicable method for effectively derivatizing cellulose.

关键词： regenerated cellulose     cellulose oleate     sonochemistry     degree of substitution     thermoplasticity    

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Dynamic contribution of variable-speed wind energy conversion system in system frequency regulation

Yajvender Pal VERMA, Ashwani KUMAR

《能源前沿（英文）》 2012年 第6卷 第2期   页码 184-192 doi: 10.1007/s11708-012-0185-y

摘要： Frequency regulation in a generation mix having large wind power penetration is a critical issue, as wind units isolate from the grid during disturbances with advanced power electronics controllers and reduce equivalent system inertia. Thus, it is important that wind turbines also contribute to system frequency control. This paper examines the dynamic contribution of doubly fed induction generator (DFIG)-based wind turbine in system frequency regulation. The modified inertial support scheme is proposed which helps the DFIG to provide the short term transient active power support to the grid during transients and arrests the fall in frequency. The frequency deviation is considered by the controller to provide the inertial control. An additional reference power output is used which helps the DFIG to release kinetic energy stored in rotating masses of the turbine. The optimal speed control parameters have been used for the DFIG to increases its participation in frequency control. The simulations carried out in a two-area interconnected power system demonstrate the contribution of the DFIG in load frequency control.

关键词： doubly fed induction generator (DFIG)     load frequency control     inertial control     wind energy conversion system (WECS)    

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Micro/nanofluidics-enabled energy conversion and its implemented devices

Yang YANG, Jing LIU

《能源前沿（英文）》 2011年 第5卷 第3期   页码 270-287 doi: 10.1007/s11708-010-0126-6

摘要： Most people were not aware of the role of energy as a basic force that drives the development and economic growth of the world until the two great oil crises occurred. According to the conservation law, energy not only exists in various forms but is also capable of being converted from one form to another. The common forms of energy are mechanical energy, chemical energy, internal energy, electrical energy, atomic energy, and electromagnetic energy, among others. The fluids in nature serve as the most common carriers and media in the energy conversion process. Following the rapid development of microelectromechanical systems (MEMS) technology, the energy supply and conversion issue in micro/nano scale has also been introduced in research laboratories worldwide. With unremitting efforts, great quantities of micro/nano scale energy devices have been investigated. Micro/nanofluid shows distinct features in transporting and converting energy similar to their counterpart macroscale tasks. In this paper, a series of micro/nanofluid-enabled energy conversion devices is reviewed based on the transformation between different forms of energy. The evaluation and contradistinction of their performances are also examined. The role of micro/nanofluid as media in micro/nano energy devices is summarized. This contributes to the establishment of a comprehensive and systematic structure in the relationship between energy conversion and fluid in the micro/nano scale. Some fundamental and practical issues are outlined, and the prospects in this challenging area are explored.

关键词： micro/nanofluid     different energy forms     energy conversion     medium role    

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Conversion of polyethylene to gasoline: Influence of porosity and acidity of zeolites

《能源前沿（英文）》   页码 763-774 doi: 10.1007/s11708-023-0897-1

摘要： Plastic waste is causing serious environmental problems. Developing efficient, cheap and stable catalytic routes to convert plastic waste into valuable products is of great importance for sustainable development, but remains to be a challenging task. Zeolites are cheap and stable, but they are usually not efficient for plastic conversion at a low temperature. Herein a series of microporous and mesoporous zeolites were used to study the influence of porosity and acidity of zeolite on catalytic activity for plastics conversion. It was observed that H-Beta zeolite was an efficient catalyst for cracking high-density polyethylene to gasoline at 240 °C, and the products were almost C4–C12 alkanes. The effect of porosity and acidity on catalytic performance of zeolites was evaluated, which clearly visualized the good performance of H-Beta due to high surface area, large channel system, large amount accessible acidic sites. This study provides very useful information for designing zeolites for efficient conversion of plastics.

关键词： plastics conversion     polyethylene     zeolites     acidity     porosity    

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Gold modified cobalt-based Fischer-Tropsch catalysts for conversion of synthesis gas to liquid fuels

Alan J. McCue, Jura Aponaviciute, Richard P.K. Wells, James A. Anderson

《化学科学与工程前沿（英文）》 2013年 第7卷 第3期   页码 262-269 doi: 10.1007/s11705-013-1334-5

摘要： The addition of Au as a promoter/modifier for alumina supported Co catalyst has been studied by combined high temperature, high pressure Fourier transform infrared (FTIR) and on-line gas chromatography. The combination of these tools permitted the state of the active catalyst surface to be monitored while following the elution of reaction products during the first 5–7 h on stream of the catalyst. The catalysts under study were a 10%Co/Al O and a 2.5%Au/10%Co/Al O Samples were characterised before use using Raman and temperature programmed reduction (TPR). During the initial stages of reaction, hydrocarbons were built up on the surface of the catalyst as monitored by FTIR and the nature and amount of these species were assessed in terms of CH /CH ratio and the density of these alkyl fragments by employing absorption coefficients for the individual components. The nature and reducibility of the Co particles were modified by the presence of Au while the later also shifted the CO/H balance by acting as an effective water-gas shift catalyst during the early stages of reaction. This characteristic was lost during reaction as a consequence of redistribution of the two metallic phases.

关键词： gold modified catalyst     conversion of synthesis gas    

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A review on front end conversion in ocean wave energy converters

Nagulan SANTHOSH,Venkatesan BASKARAN,Arunachalam AMARKARTHIK

《能源前沿（英文）》 2015年 第9卷 第3期   页码 297-310 doi: 10.1007/s11708-015-0370-x

摘要： Harvesting the energy from ocean waves is one of the greatest attractions for energy engineers and scientists. Till date, plenty of methods have been adopted to harvest the energy from the ocean waves. However, due to technological and economical complexity, it is intricate to involve the majority of these energy harvesters in the real ocean environment. Effective utilization and sustainability of any wave energy harvester depend upon its adaptability in the irregular seasonal waves, situation capability in maximum energy extraction and finally fulfilling the economic barriers. In this paper, the front end energy conversions are reviewed in detail which is positioned in the first stage of the wave energy converter among other stages such as power take off (PTO) and electrical energy conversion. If the recent development of these front end energy conversion is well known then developing wave energy converter with economic and commercial viability is possible. The aim of this review is to provide information on front end energy conversion of a point absorber and emphasize the strategies and calamity to be considered in designing such kinds of devices to improve the energy harvesting competence. This will be useful to the engineers for speeding up the development of a matured point absorbing type wave energy converter.

关键词： wave energy converter     point absorbers     power take off (PTO)     front end energy conversion    

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Co anchored on porphyrinic triazine-based frameworks with excellent biocompatibility for conversion of

《化学科学与工程前沿（英文）》 2022年 第16卷 第12期   页码 1761-1771 doi: 10.1007/s11705-022-2195-6

摘要： Microbial electrosynthesis is a promising alternative to directly convert CO2 into long-chain compounds by coupling inorganic electrocatalysis with biosynthetic systems. However, problems arose that the conventional electrocatalysts for hydrogen evolution may produce extensive by-products of reactive oxygen species and cause severe metal leaching, both of which induce strong toxicity toward microorganisms. Moreover, poor stability of electrocatalysts cannot be qualified for long-term operation. These problems may result in poor biocompatibility between electrocatalysts and microorganisms. To solve the bottleneck problem, Co anchored on porphyrinic triazine-based frameworks was synthesized as the electrocatalyst for hydrogen evolution and further coupled with Cupriavidus necator H16. It showed high selectivity for a four-electron pathway of oxygen reduction reaction and low production of reactive oxygen species, owing to the synergistic effect of Co–Nx modulating the charge distribution and adsorption energy of intermediates. Additionally, low metal leaching and excellent stability were observed, which may be attributed to low content of Co and the stabilizing effect of metalloporphyrins. Hence, the electrocatalyst exhibited excellent biocompatibility. Finally, the microbial electrosynthesis system equipped with the electrocatalyst successfully converted CO2 to poly-β-hydroxybutyrate. This work drew up a novel strategy for enhancing the biocompatibility of electrocatalysts in microbial electrosynthesis system.

关键词： microbial electrosynthesis     hydrogen evolution reaction     metalloporphyrins     biocompatibility     CO2 conversion    

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NO conversion by positive streamer discharge—effects of gas compositions and reaction conditions

HE Wei, ZHU Tianle, LI Jing

《环境科学与工程前沿（英文）》 2007年 第1卷 第2期   页码 153-158 doi: 10.1007/s11783-007-0027-z

摘要： The effects of gas compositions and reaction conditions on NO conversion by positive streamer discharge were experimentally investigated by using a link tooth wheel-cylinder reactor. The results showed that NO conversion increased w

关键词： conversion     streamer discharge     wheel-cylinder     positive streamer    

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Efficient conversion of lignin to alkylphenols over highly stable inverse spinel MnFeO catalysts

《化学科学与工程前沿（英文）》 2023年 第17卷 第8期   页码 1085-1095 doi: 10.1007/s11705-022-2236-1

摘要： The aromatic properties of lignin make it a promising source of valuable chemicals and fuels. Developing efficient and stable catalysts to effectively convert lignin into high-value chemicals is challenging. In this work, MnFe2O4 spinel catalysts with oxygen-rich vacancies and porous distribution were synthesized by a simple solvothermal process and used to catalyze the depolymerization of lignin in an isopropanol solvent system. The specific surface area was 110.5 m2∙g–1, which substantially increased the active sites for lignin depolymerization compared to Fe3O4. The conversion of lignin reached 94%, and the selectivity of alkylphenols exceeded 90% after 5 h at 250 °C. Underpinned by characterizations, products, and density functional theory analysis, the results showed that the catalytic performance of MnFe2O4 was attributed to the composition of Mn and Fe with strong Mn–O–Fe synergy. In addition, the cycling experiments and characterization showed that the depolymerized lignin on MnFe2O4 has excellent cycling stability. Thus, our work provides valuable insights into the mechanism of lignin catalytic depolymerization and paves the way for the industrial-scale application of this process.

关键词： lignin depolymerization     spinel     catalysts     hydrogenation    

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A spectrally selective surface structure for combined photothermic conversion and radiative sky cooling

Bin ZHAO, Xianze AO, Nuo CHEN, Qingdong XUAN, Mingke HU, Gang PEI

《能源前沿（英文）》 2020年 第14卷 第4期   页码 882-888 doi: 10.1007/s11708-020-0694-z

摘要： The sun and outer space are the ultimate heat and cold sources for the earth, respectively. They have significant potential for renewable energy harvesting. In this paper, a spectrally selective surface structure that has a planar polydimethylsiloxane layer covering a solar absorber is conceptually proposed and optically designed for the combination of photothermic conversion (PT) and nighttime radiative sky cooling (RC). An optical simulation is conducted whose result shows that the designed surface structure (i.e., PT-RC surface structure) has a strong solar absorption coefficient of 0.92 and simultaneously emits as a mid-infrared spectral-selective emitter with an average emissivity of 0.84 within the atmospheric window. A thermal analysis prediction reveals that the designed PT-RC surface structure can be heated to 79.1°C higher than the ambient temperature in the daytime and passively cooled below the ambient temperature of approximately 10°C in the nighttime, indicating that the designed PT-RC surface structure has the potential for integrated PT conversion and nighttime RC utilization.

关键词： solar energy     photothermic conversion     radiative sky cooling     spectral selectivity     multilayer film    

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Catalytic conversion of biomass-derived compounds to various amino acids: status and perspectives

《化学科学与工程前沿（英文）》 2023年 第17卷 第7期   页码 817-829 doi: 10.1007/s11705-022-2254-z

摘要： Amino acids are important nitrogen-containing chemicals that have a variety of applications. Currently, fermentation is the widely employed method to produce amino acids; however, the products are mostly limited to natural amino acids in the L-configuration. Catalytic synthesis is an alternative approach for the synthesis of amino acids with different types and configurations, where the use of renewable biomass-based feedstocks is highly attractive. To date, several lignocellulose and triacylglycerol-derived intermediates, typically α-keto acids and α-hydroxyl acids, have been transformed into amino acids via the amination reaction in the presence of additional nitrogen sources (i.e., NH3·H2O). Making full use of inherent nitrogen in biomass (i.e., chitin and protein) to produce amino acids avoids the use of extra nitrogen sources and meets the requirements of green chemistry, which is attracting increasing attention. In this review, we summarize different chemical-catalytic systems for the transformation of biomass to amino acids. An outlook on the challenges and opportunities for more effective production of amino acids from biomass by catalytic methods is provided.

关键词： biomass     amino acids     chitin     nitrogen-containing compounds     lignocellulose    

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标题 作者 时间 类型 操作

Multistep conversion of cresols by phenol hydroxylase and 2,3-dihydroxy-biphenyl 1,2-dioxygenase

Shengnan SHI,Fang MA,Tieheng SUN,Ang LI,Jiti ZHOU,Yuanyuan QU

期刊论文

Microfluidic dual loops reactor for conducting a multistep reaction

Si Hyung Jin, Jae-Hoon Jung, Seong-Geun Jeong, Jongmin Kim, Tae Jung Park, Chang-Soo Lee

期刊论文

Hydrogel photocatalysts for efficient energy conversion and environmental treatment

期刊论文

Biological conversion pathways of sulfate reduction ammonium oxidation in anammox consortia

Zhen Bi, Deqing Wanyan, Xiang Li, Yong Huang

期刊论文

Sustainable conversion regenerated cellulose into cellulose oleate by sonochemistry

期刊论文

Dynamic contribution of variable-speed wind energy conversion system in system frequency regulation

Yajvender Pal VERMA, Ashwani KUMAR

期刊论文

Micro/nanofluidics-enabled energy conversion and its implemented devices

Yang YANG, Jing LIU

期刊论文

Conversion of polyethylene to gasoline: Influence of porosity and acidity of zeolites

期刊论文

Gold modified cobalt-based Fischer-Tropsch catalysts for conversion of synthesis gas to liquid fuels

Alan J. McCue, Jura Aponaviciute, Richard P.K. Wells, James A. Anderson

期刊论文

A review on front end conversion in ocean wave energy converters

Nagulan SANTHOSH,Venkatesan BASKARAN,Arunachalam AMARKARTHIK

期刊论文

Co anchored on porphyrinic triazine-based frameworks with excellent biocompatibility for conversion of

期刊论文

NO conversion by positive streamer discharge—effects of gas compositions and reaction conditions

HE Wei, ZHU Tianle, LI Jing

期刊论文

Efficient conversion of lignin to alkylphenols over highly stable inverse spinel MnFeO catalysts

期刊论文

A spectrally selective surface structure for combined photothermic conversion and radiative sky cooling

Bin ZHAO, Xianze AO, Nuo CHEN, Qingdong XUAN, Mingke HU, Gang PEI

期刊论文

Catalytic conversion of biomass-derived compounds to various amino acids: status and perspectives

期刊论文