Modelling the production of ethyl butyrate catalysed by Candida rugosa lipase immobilised in polyuretane foams

Response surface methodology was used to model and optimise the esterification of ethanol with butyric acid in n-hexane, catalysed by Candida rugosa lipase immobilised in two hydrophilic polyurethane foams (“FHP 2002TM” and “FHP 5000TM”). Experiments were carried out following central composite rotatable designs (CCRD), as a function of the initial water activity of the biocatalyst (aw), initial butyric acid concentration (A) and ethanol:acid molar ratio (MR) in the organic medium. Ester production increased with increasing aw of the biocatalysts, probably due to the hydrophilicity of both substrates in contrast with the hydrophobicity of the product, which is released to the bulk medium. Thus, for each biocatalyst (aw = 0.98) another CCRD was performed as a function of A and MR. With both preparations, higher conversions (>95%) were observed for low A values. For the “FHP 2002TM” system, a maximum ester production of 0.23M is expected, after 18-h reaction, at initial 0.35M A and 1.51 MR, corresponding to aw of 0.95 and 0.84MA and 1.65Methanol in lipase microenvironment.With “FHP 5000TM” system, predicted initial conditions of 0.54M A and 0.75 MR (0.32M A; 0.75M ethanol in microenvironment; aw of 0.95), will lead to the maximum ester production of 0.27 M. These maxima were experimentally confirme

Emissões de CO2 observadas durante a reforma de canavial.

Resumo: Os fluxos de CO2 de um solo muito argiloso foram medidos utilizando-se o método da covariância de vórtices durante a reforma de um canavial realizada com operações de preparo convencional ao longo de 42 dias, entre agosto e outubro de 2015, em Pirassununga (SP). O total acumulado dos fluxos foi 165,7 g C m-2 (607,6 g CO2 m-2), representando 4% do estoque de carbono na camada superficial de 0,2 m de solo, estimado em 4.142 g C m-2. A dependência dos fluxos de CO2 com a umidade e a temperatura do solo indicaram que os fluxos foram menores para o solo mais seco e maiores temperaturas do solo, demonstrando que os efeitos destes fatores individualmente não são multiplicativos. Abstract: The CO2 soil fl uxes were measured by the eddy covariance method during the sugarcane re-establishment under conventional tillage in a high clayey soil in Pirassunuga (SP). The sum of fl uxes over 42 days was 165.7 g C m-2 (607.6 g CO2 m-2) and represented 4% of the soil carbon stock in the surface layer of 0.2 m (4,142 g C m-2). Our results contradict the multiplicative eff ects of soil moisture and temperature as the soil respiration decreased due to the warming under dry soil conditions

The structure of the KtrAB potassium transporter

In bacteria, archaea, fungi and plants the Trk, Ktr and HKT ion transporters are key components of osmotic regulation, pH homeostasis and resistance to drought and high salinity. These ion transporters are functionally diverse: they can function as Na+ or K+ channels and possibly as cation/K+ symporters. They are closely related to potassium channels both at the level of the membrane protein and at the level of the cytosolic regulatory domains. Here we describe the crystal structure of a Ktr K+ transporter, the KtrAB complex from Bacillus subtilis. The structure shows the dimeric membrane protein KtrB assembled with a cytosolic octameric KtrA ring bound to ATP, an activating ligand. A comparison between the structure of KtrAB-ATP and the structures of the isolated full-length KtrA protein with ATP or ADP reveals a ligand-dependent conformational change in the octameric ring, raising new ideas about the mechanism of activation in these transporters.We are grateful for access to ID14-1/ID14-4/ID-29 at ESRF (through the Portuguese BAG), PXII at SLS, XRD1 at ELETTRA and PROXIMA1 at SOLEIL and thank the respective support staff. A.S. was supported by FEBS (Long term fellowship). This work was funded by EMBO (Installation grant), by FEDER funds through the Operational Competitiveness Program-COMPETE and by National Funds through FCT-Fundacao para a Ciencia e a Tecnologia under the projects FCOMP-01-0124-FEDER-022718 (PEst-C/SAU/LA0002/2011), FCOMP-01-0124-FEDER-009028 (PTDC/BIA-PRO/099861/2008) and FCOMP-01-0124-FEDER-010781 (PTDC/QUI-BIQ/105342/2008). We also thank G. Gabant and M. Cadene at the 'Plateforme de Spectrometrie de Masse' at CBM, CNRS, Orleans for mass spectrometry analysis, and C. Harley for critical reading of the manuscript

Rapid assessment survey for exotic benthic species in the São Sebastião Channel, Brazil

The study of biological invasions can be roughly divided into three parts: detection, monitoring, mitigation. Here, our objectives were to describe the marine fauna of the area of the port of São Sebastião (on the northern coast of the state of São Paulo, in the São Sebastião Channel, SSC) to detect introduced species. Descriptions of the faunal community of the SSC with respect to native and allochthonous (invasive or potentially so) diversity are lacking for all invertebrate groups. Sampling was carried out by specialists within each taxonomic group, in December 2009, following the protocol of the Rapid Assessment Survey (RAS) in three areas with artificial structures as substrates. A total of 142 species were identified (61 native, 15 introduced, 62 cryptogenic, 4 not classified), of which 17 were Polychaeta (12, 1, 1, 3), 24 Ascidiacea (3, 6, 15, 0), 36 Bryozoa (17, 0, 18, 1), 27 Cmdana (2, 1, 24, 0), 20 Crustacea (11, 4, 5, 0), 2 Entoprocta (native), 16 Mollusca (13, 3, 0, 0). Twelve species are new occurrences for the SSC. Among the introduced taxa, two are new for coastal Brazil. Estimates of introduced taxa are conservative as the results of molecular studies suggest that some species previously considered cryptogenic are indeed introduced. We emphasize that the large number of cryptogenic species illustrates the need for a long-term monitoring program, especially in areas most susceptible to bioinvasion. We conclude that rapid assessment studies, even in relatively well-known regions, can be very useful for the detection of introduced species and we recommend that they be carried out on a larger scale in all ports with heavy ship traffic.Center of Marine Biology of the University of São Paulolhabela Yacht ClubCAPES-PROCAD 2007/150FAPESP (2004/09961-4; 2006/58226-0; 2010/06927-0)CAPES (Pró-Equipamentos and Prodoc projects)Boticário FoundationCNPqCAPESFAPESP (2008/10619-0)PNPD/CAPESFACEPE (BCT 0039-1.08/10)NP-BioMar, USPSpecial Issue: “Proceedings of the 3rd Brazilian Congress of Marine Biology”. A.C. Marques, L.V.C. Lotufo, P.C. Paiva, P.T.C. Chaves & S.N. Leitão (Guest Editors