Pré-tratamento de bagaço de cana com CO2 supercrítico na presença de etanol e líquido iônico : pré-otimização das variáveis do processo e avaliação da acessibilidade do substratos produzidos

Orientador : Prof. Dr. Luiz Pereira RamosTese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Exatas, Programa de Pós-Graduação em Química. Defesa: Curitiba, 24/02/2014Inclui referênciasResumo: Uma nova tecnologia de pré-tratamento de bagaço de cana-de-açúcar foi desenvolvida empregando dióxido de carbono supercrítico e etanol (scCO2/EtOH) na presença de acetato de 1-butil-metil-imidazólio (Bmim[OAc]). Os experimentos foram realizados por 2 h variando a temperatura (110 a 180 °C), a pressão (195 a 250 bar) e a quantidade de Bmim[OAc] em relação à massa seca de material (0:1 a 1:1 Bmim[OAc]/bagaço). De acordo com os resultados, a concentração de Bmim[OAc] e a pressão do sistema favorecem a deslignificação e o aumento no teor de anidroglucose no substrato, ao passo que o aumento da temperatura favorece a diminuição no teor de anidroxilose no substrato. Os melhores resultados proporcionaram 41 % de deslignificação gerando um substrato com teor de 74 % de polissacarídeos. Como resultado da deslignificação, ocorreu o aumento da acessibilidade do substrato à hidrólise enzimática, que gerou conversão de 70 % de glucanas em glucose e 92 % de xilanas em xilose após 12 h de reação quando empregados 10 mg g-1 de Cellic CTec2® (Novozymes) por substrato seco. Os líquidos iônicos (LI) contendo ânion acetato foram mais fáceis de recuperar após o pré-tratamento com scCO2/EtOH do que o LI contendo ânion cloreto, onde o emprego de Bmim[Cl] resultou em retenção de 25 % da massa inicial de LI no material, fato que levou a inativação das enzimas. Além disso, os LIs Bmim[OAc] e Emim[OAc] deslignificaram mais o material do que o Bmim[Cl], apresentando 42 %, 44 % e 36 % de deslignificação, respectivamente. Comportamento similar foi obtido para aumentos na distância interfibrilar de 44 %, 49 % e 9 %, e na largura do cristal de 17 %, 20 % e 9 %, respectivamente, ao passo que não foram encontradas variações estatisticamente significativas para os valores de índice de cristalinidade (CrIWAXS). A acessibilidade dos substratos à hidrólise foi investigada mediante avaliação da capacidade de diferentes preparações enzimáticas em liberar açúcares redutores totais (ARTot), insolúveis (ARInsol) e solúveis na presença de gluconolactona (ARISol). Tais medidas foram então utilizadas para expressar as atividades celulásica total, endoglucanásica e exoglucanásica, sendo a atividade -glucosidásica (AR?Sol) calculada pela subtração entre ARSol e ARISol. A hidrólise de celulose com enzimas purificadas revelou que tanto exoglucanases (ExG) quanto endoglucanases (EnG) do Trichoderma reseei atuam na degradação da celulose em duas etapas, a primeira gerando açúcares redutores insolúveis (ARInsol) e a segunda causando a diminuição destes com o concomitante aumento na produção de açúcares redutores solúveis (ARSol). Já os experimentos realizados empregando os preparados enzimáticos multi-componentes revelaram que o aumento na quantidade de EG-II em preparado contendo CHB-I aumentou linearmente a produção de ARTot na presença e na ausência de ?-glucosidase (?G). Na ausência de ?G, o grau de efeito de sinergia (DSE) devido à presença de EG-II em preparado contendo CBH-I foi majoritariamente maior que 1 para a produção de ARTot e ARInsol. Já na presença de ?G, o DSE para a produção de ARInsol manteve-se praticamente igual a 1, enquanto que estes valores foram maiores que 1 para a produção de ARTot ARISol e AR?Sol. Para a hidrólise dos substratos pré-tratados, a atividade ExG foi mais importante do que a atividade EnG e o pré-tratado na presença de Emim[OAc] apresentou maior suscetibilidade à hidrólise enzimática, comparado ao obtido na presença de Bmim[OAc], principalmente na presença de ?G. Na hidrólise dos substratos pré-tratados também foram identificados efeitos de sinergia entre EG-I e CBHII, sendo a sinergia na produção do ARTot principalmente gerada pela produção de ARInsol. Os valores de atividade específica aparente (AEA) para a hidrólise de papel de filtro Whatman N°1 demonstraram sinergia devido à presença de EG-II em preparado enzimático contendo CBH-I e de ?G em preparado contendo celulases, ao passo que estas variáveis provocaram diminuição nos valores de AEA para a hidrólise dos substratos pré-tratados na presença de LI. Com base nos dados obtidos, foi comprovado que, para o pré-tratamento por scCO2/EtOH-LI, o Bmim[OAc] apresentou-se como o melhor co-solvente, gerando um substrato de maior suscetibilidade à hidrólise enzimática devido à deslignificação e as mudanças na estrutura supramolecular da celulose. Palavras-chave: bagaço de cana, pré-tratamento, líquido iônico, dióxido de carbono supercrítico, hidrólise enzimática, sinergia.Abstract: A new pre-treatment technology of sugarcane bagasse was developed using supercritical carbon dioxide and ethanol (scCO2/EtOH) in the presence of 1-butyl-3-methyl-imidazolium acetate (Bmim[OAc]) as a co-solvent. The experiments were carried out along 2 h varying the temperature (110 °C to 180 °C), pressure (195 Bar to 250 Bar) and amount of Bmim[OAc] in relation to the dry mass of material (0:1 to 1:1 Bmim[OAc]:bagasse). According to the results, the concentration of Bmim[OAc] and pressure of the system favour the delignification and the content of anhydrousglucose on the substrate, while the increase of temperature favours the decrease on the anhydrousxylose content on the substrate. The best results provided 41 % of delignification generating a substrate with 74 % of polysaccharides content. As a result of the delignification, the increased substrate accessibility to enzymatic hydrolysis occurred, which led to 70 % of glucans conversion and 92 % of xylans conversion after 12 h of reaction when using 10 mg g-1 of Cellic CTec2® (Novozymes) per dry substrate. The ILs containing acetate anion showed to be easier to recovery after the pre-treatment with scCO2/EtOH than the IL containing chloride anion, where the using of Bmim[Cl] resulted on the retaining of 25 % of initial mass of IL on the material, fact that led to the inactivation of enzymes. Furthermore, the ILs Bmim[OAc] and Emim[OAc] removed more lignin than Bmim[Cl], showing 42 %, 44 % and 36 % of delignification, respectively. Similar behaviour was obtained to the increase on the interfibrillar distance of 44 %, 49 % and 9 %, and on crystal width of 17 %, 20 % and 9 %, respectively, while statistically significant differences were not found in the values of crystallinity index (CrIWAXS). The susceptibility of the substrates to the hydrolysis was investigated by assessing the ability of different enzymatic preparations on releasing total (RSTot), insoluble (RSInsol) and soluble reducing sugars on the presence of gluconolactone (RSISol). Such measures were then used to express the total cellulasic, endoglucanase and exoglucanase activities, being the ?-glucosidasic activity (AR?Sol) calculated by subtraction between RSSol and RSISol. The hydrolysis of cellulose with the purified enzymes revealed that both exoglucanases (ExG) and endoglucanases (EnG) from Trichoderma reseei act on the cellulose degradation in two steps, first generating RSInsol, and the second by the decrease of these RS and concomitant increase on the RSSol yield. On the other hand, the experiments carried out using multi-component enzymatic preparations revealed that increasing on the EG-II amount on preparations containing CBH-I increased linearly the total reducing sugars RSTot yield, in the presence and absence of ?-glucosidase (?G). In the absence of ?G, the degree of synergistic effect (DSE) due to the presence of EG-II on preparation containing CBH-I was majoring higher than 1 for the RSTot and RSInsol yields. However, in the presence of ?G the DSE for the RSInsol yield kept practically equals 1, while to the RSTot RSISol and RS?Sol yields were higher than 1. To the hydrolysis of pre-treated substrates, the ExG activity was more important than the EnG activity, and the pre-treated in the presence of Emim[OAc] showed higher susceptibility to the enzymatic hydrolysis, in comparison to the presence of Bmim[OAc], especially in the presence of ?G. On the hydrolysis on pre-treated substrates effects of synergy between EG-I and CBH-II were also identified, being the synergy caused on RSTot yield generated mainly by RSInsol yield. The values of Apparent Specific Activity (ASA) for the Whatman N°1 filter paper hydrolysis showed synergy due to the presence of EG-II on enzymatic preparation containing CBH-I and due ?G on enzymatic preparation containing cellulases, while that those variables caused decrease on the ASA values for the hydrolysis of pre-treated substrates in the presence of IL. Based on the obtained data, it was proven that for the pre-treatment by scCO2/EtOH-LI, the Bmim[OAc] showed as the best co-solvent, generating a substrate of higher susceptibility to the enzymatic hydrolysis, due to the delignification and changes on the supramolecular structure of cellulose. Key-words: sugarcane bagasse, pretreatment, ionic liquid, supercritical carbon dioxide, enzymatic hydrolysis, sinergism

Synthesis, characterization and application of [CTA+]MCM-41 in the catalytic conversion of soybean oil to fatty acid methyl esters

The transesterification of vegetable oil and/or animal fats in homogeneous alkaline medium is still the most widely used method for the production of biodiesel. However, this process requires raw materials with low acidity and moisture content to prevent undesirable side reactions such as saponification, which leads to emulsification and promotes losses in the reaction yield. Many solid compounds can be used in catalytic processes to reduce these limitations. Heterogeneous catalysts allow easy separation of the reaction media and have the possibility of reuse in several cycles. In this work, [CTA+]MCM-41 molecular sieves were synthesized and characterized by several methods (XRD, SEM, TGA and BET) to be applied in the methanolysis of soybean oil. The resulting materials were characterized as mesoporous solids of type IV with similar textural properties and thermal stability. The catalytic activity of [CTA+]MCM-41 in soybean oil methanolysis was analyzed by gel permeation chromatography (GPC) and the best solid catalyst was applied in a factorial design that was validated by Analysis of Variance (ANOVA). The oil:methanol molar ratio and the catalyst concentration were the variables with the highest statistical effects, with the latter showing a quadratic profile in relation to the response function. The best conversion was achieved at 343 K, 30 min and 3.75 wt % catalyst, which corresponded to a product with 99.2% in fatty acid methyl esters. Calcination caused a total loss in catalytic activity due to the removal of CTA+ cations from the mesoporous solids. Hence, such activity was associated with the formation of (SiO-)(CTA+) ion pairs at the surface of the solid catalys

Catálogo de plantas e fungos do Brasil

"Parabenizo a todos os botânicos que contribuíram para completar o presente catálogo. O Brasil é o país que provavelmente possui a maior flora do mundo, portanto, a produção de uma lista completa dessa flora é uma extensa tarefa. Os coordenadores mobilizaram uma grande equipe de pessoas para compilar a lista, e é ótimo ver que este projeto, diferentemente do que se observa em outros países, foi coordenado no Brasil. Isto demonstra o alto nível e a capacidade da comunidade botânica brasileira que se desenvolveu rapidamente nas últimas décadas. Este catálogo, por ter sido preparado na sua maioria por especialistas dos grupos estudados, mostra quais espécies são correntemente aceitas pelos botânicos envolvidos. As espécies foram padronizadas por meio da citação de materiais-voucher, a maioria dos quais foi coletada por brasileiros e está alojada em herbários do Brasil. A informação a respeito da distribuição geográfica de cada espécie será extremamente útil para fins de conservação, e é interessante notar o número expressivo de espécies endêmicas do Brasil. Este catálogo certamente será utilizado por estudantes de diversas áreas envolvendo botânica, ecologia e outras, e tenho certeza de que a sua existência estimulará futuras pesquisas a respeito de plantas brasileiras e que a sua versão online o manterá atualizado. O desafio agora é conservar os muitos ecossistemas diferentes nos quais estas espécies ocorrem, para manter a diversidade botânica do país.

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good

Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI

Search for stop and higgsino production using diphoton Higgs boson decays

Results are presented of a search for a "natural" supersymmetry scenario with gauge mediated symmetry breaking. It is assumed that only the supersymmetric partners of the top-quark (stop) and the Higgs boson (higgsino) are accessible. Events are examined in which there are two photons forming a Higgs boson candidate, and at least two b-quark jets. In 19.7 inverse femtobarns of proton-proton collision data at sqrt(s) = 8 TeV, recorded in the CMS experiment, no evidence of a signal is found and lower limits at the 95% confidence level are set, excluding the stop mass below 360 to 410 GeV, depending on the higgsino mass

Search for anomalous production of events with three or more leptons in pp collisions at √s = 8TeV

Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published articles title, journal citation, and DOI.A search for physics beyond the standard model in events with at least three leptons is presented. The data sample, corresponding to an integrated luminosity of 19.5fb-1 of proton-proton collisions with center-of-mass energy s=8TeV, was collected by the CMS experiment at the LHC during 2012. The data are divided into exclusive categories based on the number of leptons and their flavor, the presence or absence of an opposite-sign, same-flavor lepton pair (OSSF), the invariant mass of the OSSF pair, the presence or absence of a tagged bottom-quark jet, the number of identified hadronically decaying τ leptons, and the magnitude of the missing transverse energy and of the scalar sum of jet transverse momenta. The numbers of observed events are found to be consistent with the expected numbers from standard model processes, and limits are placed on new-physics scenarios that yield multilepton final states. In particular, scenarios that predict Higgs boson production in the context of supersymmetric decay chains are examined. We also place a 95% confidence level upper limit of 1.3% on the branching fraction for the decay of a top quark to a charm quark and a Higgs boson (t→cH), which translates to a bound on the left- and right-handed top-charm flavor-violating Higgs Yukawa couplings, λtcH and λctH, respectively, of |λtcH|2+|λctH|2<0.21

Measurement of associated W plus charm production in pp collisions at √s=7 TeV

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