Optimized hybrid nanospheres immobilizing Rhizomucor miehei lipase for chiral biotransformation

[EN] In this study, the immobilization of Rhizomucor miehei lipase into hybrid nanospheres containing a liposomal core was reported. Organic internal liposomal enzyme phase was protected by inorganic silica matrix, obtained with and without surfactant, that stabilizes the internal organic phase and isolates and protects the bioactive molecules. The optimized heterogeneous catalyst thus prepared was used for enantioselective esterification of (R,S)-ibuprofen. The influence of several catalytic parameters on the activity of hybrid nanospheres (type of solvent, nature of the alcohol, reaction temperature, etc.,) was investigated. The heterogeneous biocatalysts best performed at 37 degrees C, using isooctane as solvent and 1-propanol as alcohol (with ester yield ranging between 78 and 93%). High activity and stability (up to nine reaction cycles) of enzyme-immobilized hybrid nanospheres, with respect to the free form, were observed. R. miehei lipase, both in its free and immobilized forms, reacts only with the S(+) enantiomer of (R,S)-ibuprofen, in all the tested reaction conditions. (C) 2015 Elsevier Ltd. All rights reserved.The authors thank the financial support from Consolider-Ingenio MULTICAT CSD2009-00050, MAT2014-52085-C2-1-P, and Severo Ochoa Excellence Program SEV-2012-0267.Verri, F.; Díaz Morales, UM.; Macario, A.; Corma Canós, A.; Giordano, G. (2016). Optimized hybrid nanospheres immobilizing Rhizomucor miehei lipase for chiral biotransformation. Process Biochemistry. 51(2):240-248. https://doi.org/10.1016/j.procbio.2015.11.020S24024851

Consumers’ value co-creation in sharing economy: The role of social support, consumers’ ethical perceptions and relationship quality

The ancient phenomenon of ‘sharing’ has become mainstream, and transformed the traditional consumer behavior due to proliferation of online sharing economy platforms. Millions of people participate in popular sharing economy platforms (SEPs) such as Airbnb and Uber. Although sharing economy research has gained interest, yet a holistic model that explains the formation of consumer value co-creation intentions on such platforms remains absent. The purpose of this study is to develop a model of the antecedents of consumers value co-creation intentions at SEPs and evaluate it empirically. Building on social support theory, relationship quality theory, value co-creation and marketing ethics literature, we propose a theoretical model that explains the formation of consumers’ value co-creation intentions. Empirical data was collected from 342 Generation Y consumers and analyzed using structural equation modeling (SEM). The results reveal that social support influences ethical perceptions, which further influences value co-creation. Ethical perceptions also influence consumers' trust, satisfaction and commitment with the SEP. However, trust and commitment do not influence value co-creation intentions. Our study contributes to the literature on sharing economy by providing a holistic model of the antecedents of consumers’ value co-creation intentions. We also detail theoretical and managerial implications

New insights into fish ion regulation and mitochondrion-rich cells

Compared to terrestrial animals, fish have to cope with more-challenging osmotic and ionic gradients from aquatic environments with diverse salinities, ion compositions, and pH values. Gills, a unique and highly studied organ in research on fish osmoregulation and ionoregulation, provide an excellent model to study the regulatory mechanisms of ion transport. The present review introduces and discusses some recent advances in relevant issues of teleost gill ion transport and functions of gill ionocytes. Based on accumulating evidence, a conclusive model of NaCl secretion in gills of euryhaline teleosts has been established. Interpretations of results of studies on freshwater fish gill Na+/Cl− uptake mechanisms are still being debated compared with those for NaCl secretion. Current models for Na+/Cl− uptake are proposed based on studies in traditionally used model species. Many reported inconsistencies are claimed to be due to differences among species, various experimental designs, or acclimation conditions. Having the benefit of advanced techniques in molecular/cellular biology, functional genomics, and model animals, several new notions have recently been raised concerning relevant issues of Na+/Cl− uptake pathways. Several new windows have been opened particularly in terms of molecular mechanisms of ionocyte differentiation and energy metabolite transport between gill cells during environmental challenge

Electrochemical characterization of supercapacitors based on carbons derived from coffee shells

Carbons derived by pyrolysis of coffee shells treated with ZnCl2 were used as electrode materials in symmetric electrochemical supercapacitors. Scanning electron microscopy showed that the carbon from the porogen-free shells showa flake-like structure, while those fromthe ZnCl2-treated coffee shells have a loose, disjointed structure with no definite shape. X-ray diffraction studies indicated the presence of small domains of coherent and parallel stacking of the graphene sheets. The average surface area of the carbon was 842m2 g−1, with an average micropore area of 400m2 g−1. Cyclic voltammetric studies suggested a specific capacitance of about 150 F g−1. Self-discharge studies on the devices showed a large retention time

Construction of a soft X-ray beamline at the PLS

A soft X-ray beamline has been constructed at the Pohang Accelerator Laboratory (PAL). This bending magnet beamline provides photon energy from 100 to 1800eV, and high energy resolution. Various techniques, such as high resolution photoemission spectroscopy, near edge X-ray absorption fine structure, EUV and soft X-ray reflectivity, and soft X-ray scattering, can be used for wide applications to semiconductors, transition metals, thin films, self-assembled monolayers (SAMs), and organic molecules. (c) 2007 Elsevier B.V. All rights reserved.X1122sciescopu

Visible-ligth photocatalytic conversions of carbon monoxide to methane by nickel (II) oxide

Solar Fuels: Different n- and p-type semiconductors have been investigated for sustainable solar fuel production. p-Type semiconductors, such as NiO, Fe3O4, Co3O4, and CuO, are able to reduce carbon monoxide by water or hydrogen to methane (see picture). The highest CH4 yield achieved was 17.26 mmol of CH4 per gram of catalyst using NiO in an excess of H2.Financial support by the Spanish Ministry of Economy and Competitiveness (MINECO) through several actions (Severo Ochoa and grant number CTQ 2012-32315) is gratefully acknowledged.Sastre Calabuig, F.; Corma Canós, A.; García Gómez, H. (2013). Visible-ligth photocatalytic conversions of carbon monoxide to methane by nickel (II) oxide. Angewandte Chemie International Edition. 52(49):12983-12987. https://doi.org/10.1002/anie.201307851S12983129875249Dey, G. R. (2007). Chemical Reduction of CO2 to Different Products during Photo Catalytic Reaction on TiO2 under Diverse Conditions: an Overview. Journal of Natural Gas Chemistry, 16(3), 217-226. doi:10.1016/s1003-9953(07)60052-8Navalón, S., Dhakshinamoorthy, A., Álvaro, M., & Garcia, H. (2013). Photocatalytic CO2Reduction using Non-Titanium Metal Oxides and Sulfides. ChemSusChem, 6(4), 562-577. doi:10.1002/cssc.201200670Hwang, J.-S., Chang, J.-S., Park, S.-E., Ikeue, K., & Anpo, M. (2005). Photoreduction of Carbondioxide on Surface Functionalized Nanoporous Catalysts. Topics in Catalysis, 35(3-4), 311-319. doi:10.1007/s11244-005-3839-8INOUE, T., FUJISHIMA, A., KONISHI, S., & HONDA, K. (1979). Photoelectrocatalytic reduction of carbon dioxide in aqueous suspensions of semiconductor powders. Nature, 277(5698), 637-638. doi:10.1038/277637a0Kočí, K., Obalová, L., Matějová, L., Plachá, D., Lacný, Z., Jirkovský, J., & Šolcová, O. (2009). Effect of TiO2 particle size on the photocatalytic reduction of CO2. Applied Catalysis B: Environmental, 89(3-4), 494-502. doi:10.1016/j.apcatb.2009.01.010Leitner, W. (1995). Kohlendioxid als Rohstoff am Beispiel der Synthese von Ameisensäure und ihren Derivaten. Angewandte Chemie, 107(20), 2391-2405. doi:10.1002/ange.19951072005Leitner, W. (1995). Carbon Dioxide as a Raw Material: The Synthesis of Formic Acid and Its Derivatives from CO2. Angewandte Chemie International Edition in English, 34(20), 2207-2221. doi:10.1002/anie.199522071RSC Adv. 2012Fox, M. A., & Dulay, M. T. (1993). Heterogeneous photocatalysis. Chemical Reviews, 93(1), 341-357. doi:10.1021/cr00017a016Hoffmann, M. R., Martin, S. T., Choi, W., & Bahnemann, D. W. (1995). Environmental Applications of Semiconductor Photocatalysis. Chemical Reviews, 95(1), 69-96. doi:10.1021/cr00033a004Bahnemann, D. W. (2000). Current challenges in photocatalysis: Improved photocatalysts and appropriate photoreactor engineering. Research on Chemical Intermediates, 26(2), 207-220. doi:10.1163/156856700x00255Primo, A., Corma, A., & García, H. (2011). Titania supported gold nanoparticles as photocatalyst. Phys. Chem. Chem. Phys., 13(3), 886-910. doi:10.1039/c0cp00917bPrimo, A., Marino, T., Corma, A., Molinari, R., & García, H. (2011). Efficient Visible-Light Photocatalytic Water Splitting by Minute Amounts of Gold Supported on Nanoparticulate CeO2Obtained by a Biopolymer Templating Method. Journal of the American Chemical Society, 133(18), 6930-6933. doi:10.1021/ja2011498Sakthivel, S., Janczarek, M., & Kisch, H. (2004). Visible Light Activity and Photoelectrochemical Properties of Nitrogen-Doped TiO2. The Journal of Physical Chemistry B, 108(50), 19384-19387. doi:10.1021/jp046857qSakthivel, S., Shankar, M. ., Palanichamy, M., Arabindoo, B., Bahnemann, D. ., & Murugesan, V. (2004). Enhancement of photocatalytic activity by metal deposition: characterisation and photonic efficiency of Pt, Au and Pd deposited on TiO2 catalyst. Water Research, 38(13), 3001-3008. doi:10.1016/j.watres.2004.04.046Gomes Silva, C., Juárez, R., Marino, T., Molinari, R., & García, H. (2011). Influence of Excitation Wavelength (UV or Visible Light) on the Photocatalytic Activity of Titania Containing Gold Nanoparticles for the Generation of Hydrogen or Oxygen from Water. Journal of the American Chemical Society, 133(3), 595-602. doi:10.1021/ja1086358Herrmann, J.-M. (1986). Metal-TiO2Catalysts. Strong Metal-Support Interactions, 200-211. doi:10.1021/bk-1986-0298.ch020Adv. Funct. Mater. 2013Dare-Edwards, M. P., Goodenough, J. B., Hamnett, A., & Nicholson, N. D. (1981). Photoelectrochemistry of nickel(II) oxide. Journal of the Chemical Society, Faraday Transactions 2, 77(4), 643. doi:10.1039/f29817700643Grätzel, M. (2001). Photoelectrochemical cells. Nature, 414(6861), 338-344. doi:10.1038/35104607Xie, Y. P., Liu, G., Yin, L., & Cheng, H.-M. (2012). Crystal facet-dependent photocatalytic oxidation and reduction reactivity of monoclinic WO3 for solar energy conversion. Journal of Materials Chemistry, 22(14), 6746. doi:10.1039/c2jm16178hYuliati, L., & Yoshida, H. (2008). Photocatalytic conversion of methane. Chemical Society Reviews, 37(8), 1592. doi:10.1039/b710575