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Effect of noble metal nanoparticle size on CN bond cleavage performance in hydrodenitrogenation: a study

《化学科学与工程前沿(英文)》 2023年 第17卷 第12期   页码 1986-2000 doi: 10.1007/s11705-023-2337-5

摘要: Breakage of the C–N bond is a structure sensitive process, and the catalyst size significantly affects its activity. On the active metal nanoparticle scale, the role of catalyst size in C–N bond cleavage has not been clearly elucidated. So, Ru catalysts with variable nanoparticle sizes were obtained by modulating the reduction temperature, and the catalytic activity was evaluated using 1,2,3,4-tetrahydroquinoline and o-propylaniline with different C–N bond hybridization patterns as reactants. Results showed a 13 times higher reaction rate for sp3-hybridized C–N bond cleavage than sp2-hybridized C–N bond cleavage, while the reaction rate tended to increase first and then decrease as the catalyst nanoparticle size increased. Different concentrations of terrace, step, and corner sites were found in different sizes of Ru nanoparticles. The relationship between catalytic site variation and C–N bond cleavage activity was further investigated by calculating the turnover frequency values for each site. This analysis indicates that the variation of different sites on the catalyst is the intrinsic factor of the size dependence of C–N bond cleavage activity, and the step atoms are the active sites for the C–N bond cleavage. When Ru nanoparticles are smaller than 1.9 nm, they have a strong adsorption effect on the reactants, which will affect the catalytic performance of the Ru catalyst. Furthermore, these findings were also confirmed on other metallic Pd/Pt catalysts. The role of step sites in C–N bond cleavage was proposed using the density function theory calculations. The reactants have stronger adsorption energies on the step atoms, and step atoms have d-band center nearer to the Fermi level. In this case, the interaction with the reactant is stronger, which is beneficial for activating the C–N bond of the reactant.

关键词: sp3/sp2-hybridized C–N bond     noble metal nanoparticle     catalytic active site     turnover frequency     DFT    

Nitrogen distribution in the products from the hydrothermal liquefaction of sp. and sp.

《化学科学与工程前沿(英文)》 2022年 第16卷 第6期   页码 985-995 doi: 10.1007/s11705-021-2126-y

摘要: The high contents of nitrogen-containing organic compounds in biocrude obtained from hydrothermal liquefaction of microalgae are one of the most concerned issues on the applications and environment. In the project, Chlorella sp. and Spirulina sp. were selected as raw materials to investigate the influence of different reaction conditions (i.e., reaction temperature, residence time, solid loading rate) on the distribution of nitrogen in the oil phase and aqueous phase. Three main forms of nitrogen-containing organic compounds including nitrogen-heterocyclic compounds, amide, and amine were detected in biocrudes. The contents of nitrogen-heterocyclic compounds decreased with temperature while amide kept increasing. The effect of residence time on the components of nitrogen-containing organic compounds was similar with that of temperature. However, the influence of solid loading rate was insignificant. Moreover, it was also found that the differences of amino acids in the protein components in the two microalgae might affect the nitrogen distribution in products. For example, nitrogen in basic amino acids of Spirulina sp. preferred to go into the aqueous phase comparing with the nitrogen in neutral amino acids of Chlorella sp. In summary, a brief reaction map was proposed to describe the nitrogen pathway during microalgae hydrothermal liquefaction.

关键词: microalgae     hydrothermal liquefaction     biocrude     nitrogen distribution    

Application of statistical design for the production of inulinase by

RAJASIMMAN, N. RAJAMOHAN

《化学科学与工程前沿(英文)》 2011年 第5卷 第4期   页码 463-470 doi: 10.1007/s11705-011-1112-1

摘要: A Plackett-Burman design was employed for screening 18 nutrient components for the production of inulinase using sp. and pressmud as the substrate via solid-state fermentation (SSF). From the experiments, three nutrients viz. yeast extract, FeSO ·7H O, and NH NO were found to be the most significant components. Hence these three components were selected and optimized using Response Surface Methodology (RSM). The optimum conditions are: yeast extract 0.00274 g/gds, FeSO ·7H O 0.00011 g/gds and NH NO 0.00772 g/gds. The effect of the substrate concentration and initial moisture content were also studied. A substrate concentration of 12 g and an initial moisture content of 65% are optimum for the maximum production of inulinase (89 U/gds).

关键词: inulinase     pressmud     Response Surface Methodology (RSM)     streptomyces sp    

EXTRACTION AND EVALUATION OF EDIBLE OIL FROM SCHIZOCHYTRIUM SP. USING AN AQUEOUS ENZYMATIC METHOD

《农业科学与工程前沿(英文)》 2021年 第8卷 第4期   页码 623-634 doi: 10.15302/J-FASE -2021400

摘要:

Schizochytrium sp., a marine microalga, is a potential source of edible oil due to its short growth cycle and rapid lipid accumulation, especially of docosahexaenoic acid. An approach to isolate edible microalgal oil from Schizochytrium sp. using aqueous enzymatic extraction (AEE) was developed. Parameters were optimized by single-factor experiments followed by Box-Behnken design. Proteases were effective in extracting oil. The maximum free oil recovery (49.7%±0.58%) and total oil recovery (68.1%±0.94%) were obtained under optimum conditions of liquid-to-solid ratio of 4.8:1, a 2.5% enzyme concentration of papain and an extraction time of 2.2 h. There was a significant difference (P<0.05) in polyunsaturated fatty acid composition between microalgal oil obtained by AEE and by Soxhlet extraction, with the former having superior physiochemical properties and higher concentrations of bioactive components including total phenolic compounds and total tocopherols. These findings indicate a potential application of AEE for extraction of oil from Schizochytrium sp.

 

关键词: antioxidant activity / aqueous enzymatic extraction / edible microalgal oil / fatty acid composition / physicochemical properties    

Heterologous expression of

Woodfin,Jan-Hendrik Hehemann,Sheila C. Potter,Francis E. Nano

《环境科学与工程前沿(英文)》 2017年 第11卷 第2期 doi: 10.1007/s11783-017-0910-1

摘要: Maximum growth rate of mutant was 0.083 h with 5% CO . Maximum biomass concentration of mutant was 3.697 g·L . mutant can tolerate gas aeration with 15% CO . Maximum specific activity of laminarinase was 4.325 U·mg dry mass. Optimal pH and temperature of laminarinase activity were 8.0 and 70°C. The gene for the catalytic domain of thermostable endo-β-1,3-glucanase (laminarinase) LamA was cloned from Thermotoga maritima MSB8 and heterologously expressed in a bioengineered Synechococcus sp. PCC 7002. The mutant strain was cultured in a photobioreactor to assess biomass yield, recombinant laminarinase activity, and CO2 uptake. The maximum enzyme activity was observed at a pH of 8.0 and a temperature of 70°C. At a CO2 concentration of 5%, we obtained a maximum specific growth rate of 0.083 h , a biomass productivity of 0.42 g·L ·d , a biomass concentration of 3.697 g·L , and a specific enzyme activity of the mutant strain of 4.325 U·mg dry mass. All parameters decreased as CO2 concentration increased from 5% to 10% and further to 15% CO2, except enzyme activity, which increased from 5% to 10% CO2. However, the mutant culture still grew at 15% CO2 concentration, as reflected by the biomass productivity (0.26 g·L ·d ), biomass concentration (2.416 g·L ), and specific enzyme activity (3.247 U·mg dry mass).

关键词: Synechococcus sp. PCC 7002     Thermotoga maritima     LamA gene     Endo-β-1     3-glucanase     CO2 fixation    

甘油诱导的鼠李糖脂增强伯克霍尔德菌属C3中二苯并噻吩的生物降解 Article

Camila A. Ortega Ramirez, Abraham Kwan, Qing X. Li

《工程(英文)》 2020年 第6卷 第5期   页码 533-540 doi: 10.1016/j.eng.2020.01.006

摘要: 利用甘油刺激伯克霍尔德菌属C3Burkholderia sp.C3),降解其中的DBT,内容涉及以下方面:①DBT的生物降解动力学;②细菌生长;③鼠李糖脂(RL)的生物合成;④RL分泌。在增添了甘油和DBT的培养基中鉴定出了鼠李糖脂的同系物:Rha-C10-C10、Rha-Rha-C10-C10、Rha-Rha-C10-C12和Rha-Rha-C12-C12,然而,在不含甘油或添加了RL抑制剂的培养物中只鉴定出Rha-C12-C12。

关键词: 生物降解     生物修复     生物表面活性剂     生物转化     甘油     微生物代谢     鼠李糖脂    

Cultivation of sp. HQ in inland saline-alkaline water under different light qualities

《环境科学与工程前沿(英文)》 2022年 第16卷 第4期 doi: 10.1007/s11783-021-1479-2

摘要:

• Optimal growth of Chlorella in inland saline-alkaline water was achieved by blue LED.

关键词: Light quality     Chlorella     Inland saline-alkaline water     Fatty acid     Biodiesel property    

过硫酸盐诱导的缺陷氮化碳中三配位氮(N3C)空位增强光催化产过氧化氢 Article

缪蔚, 王奕杰, 刘莹, 秦贺贺, 褚成成, 毛舜

《工程(英文)》 2023年 第25卷 第6期   页码 214-221 doi: 10.1016/j.eng.2021.12.016

摘要: 其中石墨氮化碳(g-C3N4)被认为是最有前途的合成过氧化氢的光催化剂之一;并且,在g-C3N4中引入氮空位已被证明是提高其光催化活性的有效策略在此,本文提出了一种简便的过硫酸钠共晶聚合方法,制备了具有丰富三配位氮空位(N3C)的g-C3N4。本研究的结果表明,在g-C3N4中引入N3C空位可以成功地拓宽光吸收范围,抑制光激发电荷的重组,增强O2的吸附和活化富含N3C空位的g-C3N4的光催化过氧化氢产量是原始g-C3N4的4.5倍。本研究提出了在g-C3N4中引入N3C空位的新策略,为开发光催化产过氧化氢的活性催化剂提供了一种新方法。

关键词: 氮化碳     N3C空位     过氧化氢     光催化     过硫酸盐    

of cultivation strategies on the cultivation of Chlorella sp

Xiaoya Liu, Yu Hong, Peirui Liu, Jingjing Zhan, Ran Yan

《环境科学与工程前沿(英文)》 2019年 第13卷 第5期 doi: 10.1007/s11783-019-1162-z

摘要: Heterotrophic cultivation caused high level of ROS and high lipids accumulation. HMTC is the best culture strategy for improving the microalgal biomass. Chlorella sp. HQ had great nutrient removal capacity under five culture strategies. The effects of cultivation strategies (including autotrophic cultivation (AC), heterotrophic cultivation (HC), fed-batch cultivation (FC), heterotrophic+ autotrophic two-stage cultivation (HATC), and heterotrophic+ mixotrophic two-stage cultivation (HMTC)) on the growth and lipid accumulation of Chlorella sp. HQ and its total nitrogen (TN) and total phosphorus (TP) removal in secondary effluent were investigated in column photoreactors. The results showed that the TN and TP removal rates ranged between 93.72%–95.82% and 92.73%–100%, respectively, under the five different strategies. The microalgal growth potential evaluated by the maximal growth rate (Rmax) was in the order of HMTC>HC>FC>AC>HATC. The values of biomass, total lipid yield, triacylglycerols (TAGs) yield, and total lipid content of the microalga cultivated in the last 5 d increased significantly, but the TAGs productivities of the five strategies were lower than those in the first 7 d. Compared with all the other cultivation strategies, the TAGs productivity and yield after 12 d of cultivation under the heterotrophic condition reached the highest values accompanying the highest level of intracellular reactive oxygen species (ROS), in which the TAGs yield reached 40.81 mg/L at the end of the cultivation period. The peaks in TAGs yield and ROS level suggested that HC was beneficial for lipids accumulation via regulating the cellular redox status and exerting ROS stress on microalgal cells. In summary, HMTC was the best cultivation strategy for improving the microalgal biomass and HC was the best strategy for microalgal TAGs accumulation to produce biodiesel.

关键词: Chlorella sp. HQ     Cultivation strategy     lipids     Nitrogen removal     Phosphorus removal     Reactive oxygen species    

Comparison of growth and lipid accumulation properties of two oleaginous microalgae under different nutrient conditions

Qiao ZHANG,Yu HONG

《环境科学与工程前沿(英文)》 2014年 第8卷 第5期   页码 703-709 doi: 10.1007/s11783-014-0649-x

摘要: This study compared the growth and lipid accumulation properties of two oleaginous microalgae, namely, sp. LX1 and sp. HQ, under different nutrient conditions. Both algal species obtained the highest biomass, lipid content and lipid yield under low-nutrient conditions (mBG11 medium). The biomass, lipid content and lipid yield of sp. LX1 were 0.42 g·L , 22.5% and 93.8 mg·L , respectively. These values were relatively higher than those of sp. HQ (0.30 g·L , 17.1% and 51.3 mg·L , respectively). These algae were then cultivated in an SE medium that contained more nutrients; as a result, the biomass and lipid yield of sp. LX1 reduced more significantly than those of sp. HQ. Opposite results were observed in lipid and triacylglycerols (TAGs) contents. The cell sizes of both algal species under low-nutrient conditions were larger than those under high-nutrient conditions. sp. HQ cells did not aggregate, but sp. LX1 cells flocculated easily, particularly under low-nutrient conditions. In summary, low-nutrient conditions favour the growth and lipid production of both algae, but sp. LX1 outperforms sp. HQ.

关键词: Scenedesmus sp. LX1     Chlorella sp. HQ     growth rate     algal biomass     lipid accumulation     triacylglycerols (TAGs)    

Studies on culture condition of new marine bacterium sp. SY01

LAN Wenjian, MO Linfeng, LI Houjin, CAI Chuanghua, ZHOU Yipin, YAO Junhua

《化学科学与工程前沿(英文)》 2008年 第2卷 第4期   页码 443-446 doi: 10.1007/s11705-008-0065-5

摘要: New marine bacterium sp. SY01, producer of prodigiosin, was isolated from the seawaters of Sanya Bay. The culture conditions of this bacterium were investigated. sp. SY01 was cultured in 2216E media which contained tryptophan, histidine, lactonic acid, camphor, limonene, casein, diphenyl guanidine, coumarin and 1,3-dinitrobenzene, respectively. After 5 days cultivation, the extracts of different culture broths were detected by direct infusion mass spectroscopy using positive ESI mode. As the results, tryptophan, histidine and casein didn’t show any observable influences on the biosynthesis of prodigiosin. Lactonic acid, camphor, limonene, diphenyl guanidine, coumarin could inhibit the bacterium growth and prodigiosin biosynthesis to a certain extent, slower the culture broth to turn red. However, 1, 3-dinitrobenzene inhibited the bacteria to produce prodigiosin completely. MS data suggested that various metabolites with chemodiversity were produced in different culture media. In particular, a series of high-molecular-weight compounds with high relative abundances were observed in the medium containing limonene. To further optimize the culture condition, more new prodigiosin analogues and lead compounds can be obtained and the goal of “one strain-many compounds” can be achieved.

关键词: producer     high-molecular-weight     relative     culture     different culture    

Rh2O3/hexagonal CePO4 nanocatalysts for N2O decomposition

Huan Liu, Zhen Ma

《化学科学与工程前沿(英文)》 2017年 第11卷 第4期   页码 586-593 doi: 10.1007/s11705-017-1659-6

摘要: Hexagonal CePO nanorods were prepared by a precipitation method and hexagonal CePO nanowires were prepared by hydrothermal synthesis at 150 °C. Rh(NO ) was then used as a precursor for the impregnation of Rh O onto these CePO materials. The Rh O supported on the CePO nanowires was much more active for the catalytic decomposition of N O than the Rh O supported on CePO nanorods. The stability of both catalysts as a function of time on stream was studied and the influence of the co-feed (CO , O , H O or O /H O) on the N O decomposition was also investigated. The samples were characterized by N adsorption-desorption, inductively coupled plasma optical emission spectroscopy, X-ray diffraction, transmission electron microscopy, X-ray photoelectron microscopy, hydrogen temperature-programmed reduction, oxygen temperature-programmed desorption, and CO temperature-programmed desorption in order to correlate the physicochemical and catalytic properties.

关键词: Rh2O3     CePO4     N2O decomposition    

Controllable synthesis of a large TS-1 catalyst for clean epoxidation of a C=C double bond under mild

《化学科学与工程前沿(英文)》 2023年 第17卷 第6期   页码 772-783 doi: 10.1007/s11705-022-2280-x

摘要: Development of a titanium silicalite-1 (TS-1) catalyst with good crystallinity and a four-coordinate Ti framework is critical for efficient catalytic oxidation reaction under mild conditions. Herein, a size-controlled TS-1 zeolite (TS-1#0.1ACh (acetylcholine)) was synthesized via steam-assisted crystallization by introducing acetylcholine as a crystal growth modifier in the preparation process, and TS-1#0.1ACh was also employed in epoxidations of different substrates containing C=C double bonds. The crystalline sizes of the as-synthesized TS-1#0.1ACh catalysts were controlled with the acetylcholine content, and characterization results showed that the particle sizes of highly crystalline TS-1#0.1ACh zeolite reached 3.0 μm with a good Ti framework. Throughout the synthetic process, the growth rate of the crystals was accelerated by electrostatic interactions between the connected hydroxyl groups of the acetylcholine modifier and the negatively charged skeleton of the pre-zeolites. Furthermore, the TS-1#0.1ACh catalyst demonstrated maximum catalytic activity, good selectivity and high stability during epoxidation of allyl chloride. Importantly, the TS-1#0.1ACh catalyst was also highly versatile and effective with different unsaturated substrates. These findings may provide novel, easily separable and large TS-1 catalysts for efficient and clean industrial epoxidations of C=C double bonds.

关键词: size-controlled TS-1     crystal modifier     steam-assisted crystallization     epoxidation    

BORON:面向普适计算的超轻量低功耗加密设计 Article

Gaurav BANSOD,Narayan PISHAROTY,Abhijit PATIL

《信息与电子工程前沿(英文)》 2017年 第18卷 第3期   页码 317-331 doi: 10.1631/FITEE.1500415

摘要: 与轻量加密LED相比,BORON具有更低的功耗水平;与现有SP网络加密相比,BORON具有更高的吞吐量。本文还展示了BORON的安全性分析及其作为超轻量紧凑型加密的性能。

关键词: 轻量密码;SP网络;分组密码;物联网;加密;嵌入式安全    

Formation of disinfection byproducts from accumulated soluble products of oleaginous microalga after chlorination

Yu Liu, Qiao Zhang, Yu Hong

《环境科学与工程前沿(英文)》 2017年 第11卷 第6期 doi: 10.1007/s11783-017-0938-2

摘要: When microalgae are simultaneously applied for wastewater treatment and lipid production, soluble algal products (SAP) should be paid much attention, as they are important precursors for formation of disinfection byproducts (DBPs), which have potential risks for human health. sp. HQ is an oleaginous microalga that can generate SAP during growth, especially in the exponential phase. This study investigated the contribution of SAP from sp. HQ to DBP formation after chlorination. The predominant DBP precursors from SAP were identified with the 3D excitation-emission matrix fluorescence. After chlorination, a significant reduction was observed in the fluorescence intensity of five specific fluorescence regions, particularly aromatic proteins and soluble microbial by-product-like regions, accompanied with slight shifting of the peak. The produced DBPs were demonstrated to include trihalomethanes and haloacetic acids. As the algal cultivation time was extended in wastewater, the accumulated SAP strengthened the formation of DBPs. The trend for DBP formation was as follows: chloroform>dichloroacetic acid>trichloroacetic acid.

关键词: Chlorella sp. HQ     Chlorination     Disinfection byproducts     Fluorescence spectroscopy     Soluble algal products    

标题 作者 时间 类型 操作

Effect of noble metal nanoparticle size on CN bond cleavage performance in hydrodenitrogenation: a study

期刊论文

Nitrogen distribution in the products from the hydrothermal liquefaction of sp. and sp.

期刊论文

Application of statistical design for the production of inulinase by

RAJASIMMAN, N. RAJAMOHAN

期刊论文

EXTRACTION AND EVALUATION OF EDIBLE OIL FROM SCHIZOCHYTRIUM SP. USING AN AQUEOUS ENZYMATIC METHOD

期刊论文

Heterologous expression of

Woodfin,Jan-Hendrik Hehemann,Sheila C. Potter,Francis E. Nano

期刊论文

甘油诱导的鼠李糖脂增强伯克霍尔德菌属C3中二苯并噻吩的生物降解

Camila A. Ortega Ramirez, Abraham Kwan, Qing X. Li

期刊论文

Cultivation of sp. HQ in inland saline-alkaline water under different light qualities

期刊论文

过硫酸盐诱导的缺陷氮化碳中三配位氮(N3C)空位增强光催化产过氧化氢

缪蔚, 王奕杰, 刘莹, 秦贺贺, 褚成成, 毛舜

期刊论文

of cultivation strategies on the cultivation of Chlorella sp

Xiaoya Liu, Yu Hong, Peirui Liu, Jingjing Zhan, Ran Yan

期刊论文

Comparison of growth and lipid accumulation properties of two oleaginous microalgae under different nutrient conditions

Qiao ZHANG,Yu HONG

期刊论文

Studies on culture condition of new marine bacterium sp. SY01

LAN Wenjian, MO Linfeng, LI Houjin, CAI Chuanghua, ZHOU Yipin, YAO Junhua

期刊论文

Rh2O3/hexagonal CePO4 nanocatalysts for N2O decomposition

Huan Liu, Zhen Ma

期刊论文

Controllable synthesis of a large TS-1 catalyst for clean epoxidation of a C=C double bond under mild

期刊论文

BORON:面向普适计算的超轻量低功耗加密设计

Gaurav BANSOD,Narayan PISHAROTY,Abhijit PATIL

期刊论文

Formation of disinfection byproducts from accumulated soluble products of oleaginous microalga after chlorination

Yu Liu, Qiao Zhang, Yu Hong

期刊论文