34 research outputs found

    Optimization of lipase production by solid-state fermentation of olive pomace: from flask to laboratory-scale packed-bed bioreactor

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    Lipases are versatile catalysts with many applications and can be produced by solid-state fermentation (SSF) using agro-industrial wastes. The aim of this work was to maximize the production of Aspergillus ibericus lipase under SSF of olive pomace (OP) and wheat bran (WB), evaluating the effect on lipase production of C/N ratio, lipids, phenols, content of sugars of substrates and nitrogen source addition. Moreover, the implementation of the SSF process in a packed-bed bioreactor and the improvement of lipase extraction conditions were assessed. Low C/N ratios and high content of lipids led to maximum lipase production. Optimum SSF conditions were achieved with a C/N mass ratio of 25.2 and 10.2% (w/w) lipids in substrate, by the mixture of OP:WB (1:1) and supplemented with 1.33% (w/w) (NH4)2SO4. Studies in a packed-bed bioreactor showed that the lower aeration rates tested prevented substrate dehydration, improving lipase production. In this work, the important role of Triton X-100 on lipase extraction from the fermented solid substrate has been shown. A final lipase activity of 223 ± 5 U g1 (dry basis) was obtained after 7 days of fermentation.Felisbela Oliveira acknowledges the ïŹnancial support from Fundação para a CiĂȘncia e Tecnologia (FCT) of Portugal through grant SFRH/BD/87953/2012. JosĂ© Manuel Salgado was supported by grant CEB/N2020–INV/01/2016 from Project ‘‘BIOTECNORTE-Underpinning Biotechnology to foster the north of Portugal bioeconomy’’ (NORTE-01-0145-FEDER-000004). Luı ÂŽs Abrunhosa was supported by grant UMINHO/BPD/51/2015 from project UID/BIO/04469/2013 ïŹnanced by FCT/MEC (OE). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER006684) and BioTecNorte operation (NORTE-01-0145-FEDER000004) funded by the European Regional Development Fund under the scope of Norte2020–Programa Operacional Regional do Norte. Noelia PĂ©rez-RodrĂ­guez acknowledges the ïŹnancial support of FPU fellowship from the Spanish Ministry of Education, Culture and Sports. The authors thank the Spanish Ministry of Economy and Competitiveness for the ïŹnancial support of this work (Project CTQ2015-71436-C2-1-R), which has partial ïŹnancial support from the FEDER funds of the European Union.info:eu-repo/semantics/publishedVersio

    The inventory of geological heritage of the state of SĂŁo Paulo, Brazil: Methodological basis, results and perspectives

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    An inventory of geological sites based on solid and clear criteria is a first step for any geoconservation strategy. This paper describes the method used in the geoheritage inventory of the State of SĂŁo Paulo, Brazil, and presents its main results. This inventory developed by the geoscientific community aimed to identify geosites with scientific value in the whole state, using a systematic approach. All 142 geosites representative of 11 geological frameworks were characterised and quantitatively evaluated according to their scientific value and risk of degradation, in order to establish priorities for their future management. An online database of the inventory is under construction, which will be available to be easily consulted and updated by the geoscientific community. All data were made available to the State Geological Institute as the backbone for the implementation of a future state geoconservation strategy.The authors acknowledge the Science Without Borders Programme, Process 075/2012, which supported this study and the SĂŁo Paulo Research Foundation (FAPESP), Process 2011/17261-6. We also thanks C. Mazoca for his help with maps and figures.info:eu-repo/semantics/acceptedVersio

    ELECTRONIC EXCITATION OF H-2 BY POSITRON-IMPACT - AN APPLICATION OF THE SCHWINGER MULTICHANNEL METHOD

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    In this paper we report integral and differential cross sections for positron-impact excitation of the X 1SIGMA(g)+ --> B 1SIGMA(u)+ transition in H-2 for collision energies of 13.5, 15, 17.5, 20, 25 and 30 eV. These cross sections were derived from fixed-nuclei scattering amplitudes in such a way that low angular-momentum components are obtained using the Schwinger multichannel method and the large ones are treated by the first Born approximation. To our knowledge, up to date no experimental data are available for comparison. Our results differ from previous theoretical results of Mukherjee and co-workers. We discuss possible reasons for this disagreement.2791881188
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