Estudo da produção de inulinase por Kluyveromyces marxianus ATCC 36907

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro TecnologicoA produção de inulinase por Kluyveromyces marxianus ATCC 36907 foi avaliada quanto aos seguintes parâmetros fermentativos: temperatura, pH, suprimento de oxigênio, composição do meio de cultivo e concentração inicial de substrato. Algumas características da enzima foram também determinadas. Os resultados apresentaram um comportamento estável da inulinase por pelo menos 4 meses de estocagem a -20°C. A enzima extracelular mostrou-se estável até 55°C enquanto que a enzima periplasmática apresentou menor estabilidade térmica (45°C). A temperatura e o pH ótimos de atuação de ambas as enzimas foram semelhantes entre si e equivalentes a 55°C e pH 5,0, respectivamente. A temperatura ideal de cultivo do microrganismo para produção de enzima foi de 37°C, com pH controlado em 4,5. O meio de cultivo mais adequado foi o meio rico (extrato de levedura 10 g/L, bacto peptona 20 g/L e inulina 10 g/L), não sendo possível a substituição da fonte de carbono (inulina comercial) pelo extrato de chicória. Concentrações crescentes de inulina comercial, nas condições testadas, levaram a uma elevada produção de etanol. A substituição de bacto peptona (fonte de nitrogênio) por sulfato de amônio ou uréia também não apresentou resultados favoráveis à produção de enzima. A influência do suprimento de oxigênio foi avaliada baseada no coeficiente de transferência inicial de oxigênio (KLa). Valores de KLa iguais a 21, 36 e 89 h-1 foram testados e os resultados mostraram que o aumento do KLa favorece a formação de biomassa bem como de inulinase

Application of response surface methodology and central composite rotatable design (CCDR) for modelling the influence of agro-industrial waste in lactic acid biosynthesis

Lactic acid (LA) is one of the most important organic acids, with a wide range of industrial and biotechnological applications and can be produced by chemical synthesis and microbial culture. However, the biotech pathway is generally preferred because it provides an optically pure product. In this context, the purpose of this work was to evaluate LA biosynthesis by Lactobacillus amylovorus using molasses as carbon source (CS) and corn steep liquor as nitrogen source (NS) in a central composite rotatable design (CCRD) varying the concentration CS and NS, as well as to validate the model. The method for microbial culture followed an experimental design of the CCRD type, conducted without agitation, at 37ºC in Erlenmeyer flask, with pH in spontaneous evolution. The results showed that, using molasses and corn steep liquor as alternative sources, LA production ranged from 2.8 to 4.6 g/L, respectively, with the most favourable condition being 40.0 g of molasses and 250 g of corn steep liquor. It was possible, from the experimental design, to ascertain the selection of the best conditions for the microbial culture, demonstrating the feasibility of replacing CS and NS by agro-industrial waste, thus reducing the cost of producing LA

Síntese e biodegradação em solo de copolímeros de PET-co-PLLA

  A necessidade de reduzir a quantidade de resíduos plásticos descartada no meio ambiente revela a área de reciclagem como de grande interesse, tendo como uma das alternativas a reciclagem química do po-li(tereftalato de etileno) (PET) pós-consumo com poliésteres alifáticos. Portanto, neste trabalho estudou-se a reação em massa do PET pós-consumo com o poli(L-ácido lático) (PLLA), plastificado com trietil citrato de sódio, visando obter novos copoliésteres alifático-aromáticos potencialmente biodegradáveis. A copolimeri-zação foi conduzida em reator pela adição de PET (obtido de garrafas de refrigerante) e PLLA (obtido por uma reação de policondensação do L-ácido lático), variando de 10 a 90 % em massa. Em seguida, adiciona-ram-se os aditivos necessários e verteu-se em formas de silicone, obtendo os copolímeros. A técnica se mos-trou adequada para a síntese de PET-co-PLLA, sendo esta confirmada através da análise de RMN 1H. As análises de TGA indicaram que a estabilidade térmica dos copolímeros aumenta conforme aumenta o teor de PET. Após a caracterização dos copolímeros, realizou-se o ensaio de biodegradação, a qual foi acompanhado por RMN 1H, FTIR-ATR, análise visual, MEV, DSC e TGA antes e após 15, 45 e 90 dias enterradas em solo preparado. Os resultados de biodegradação revelaram que a parte alifática dos copolímeros foi a primeira a sofrer biodegradação, indicando assim a preferência dos micro-organismos presentes no solo pelo PLLA. Estes resultados indicaram que é possível sintetizar novos copolímeros a partir de garrafas de refrigerante pós-consumo, potencialmente biodegradáveis quando descartados no meio-ambiente.Palavras-chave: poli(L-ácido lático), poli(tereftalato de etileno), PET-co-PLLA, copolimerização, biodegra-dação, reciclagem

Avaliação das propriedades do biopolímero polihidroxibutirato (PHB) extraído por vermes de Zophobas morio Fabricius

Polihidroxibutirato (PHB) é um biopolímero produzido intracelularmente e acumulado como reserva de energia por muitos microrganismos, sendo o principal, a bactéria Cupriavidus necator. Logo, é necessário realizar a extração dos grânulos intracelulares do interior das células. A extração química do PHB com clorofórmio e hipoclorito de sódio é eficiente, porém, utilizam-se elevadas quantidades de clorofórmio, solvente tóxico e volátil. Assim, faz-se necessário o estudo de novas tecnologias para a extração do PHB, buscando tornar o processo viável tecnologicamente, visto que este biopolímero é um importante candidato para substituição de polipropileno (PP). Diante desse contexto, este trabalho objetivou avaliar o processo de extração do PHB por meio das larvas de Zophobas morio Fabricius, comparado ao processo químico tradicional. O PHB foi sintetizado pela bactéria Cupriavidus necator em frascos de Erlenmeyer com 300 mL de meio mineral contendo glicose e frutose como fontes de carbono. O cultivo foi conduzido por 24 h a 30 °C e 150 rpm. A biomassa obtida do cultivo foi submetida à extração química (dispersão de clorofórmio/hipoclorito de sódio) e biológica, sendo, para isto, utilizada em uma mistura 2:1 (m/m) de farelo de trigo para biomassa úmida contendo PHB como fonte de alimentação das larvas de Zophobas morio Fabricius. O PHB obtido pelos dois processos foi caracterizado por  termogravimetria (TG), calorimetria diferencial exploratória (DSC), espectroscopia na região do infravermelho com transformada de Fourier - reflexão total atenuada (FTIR/ATR), difratometria de raios-X (DRX) e microscopia eletrônica de varredura (MEV). Verificou-se que a amostra extraída pelo método biológico (PHB_EB), quando comparada com a amostra extraída pelo método químico (PHB_EQ), apresentou a mesma estrutura química e que a metodologia biológica usando larvas apresentou-se mais rápida e eficiente, garantindo a extração do PHB com elevada pureza e estabilidade térmica, com reduzida quantidade de solvente, tornando este processo mais ambientalmente amigável. Palavras-chave: Extração biológica, Polihidroxibutirato, Zophobas morio Fabricius

Obtaining and characterization of bacterial cellulose synthesized by Komagataeibacter hansenii from alternative sources of nitrogen and carbon

This work aimed to obtain and characterize bacterial cellulose (BC) membranes obtained by cultivating Komagataeibacter hansenii ATCC 23769 using mannitol, glucose, fructose, lactose, glycerol, inulin, and sucrose as carbon sources, and corn steep liquor and Prodex Lac® as alternative sources of nitrogen. The formation of the BC´s gelatinous membrane was monitored for 12 days under static conditions and a temperature of 30 ºC. After purification, the membranes were dried and characterized by thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The highest BC concentrations were found in the culture medium containing Prodex Lac® as the source of nitrogen. Among sugars, fructose and mannitol presented the best results. TGA analyzes indicate that all membranes have similar thermal behavior. The FTIR results show that the chemically synthesized membranes are equivalent to the structures cited in the literature. The micrographs obtained by SEM showed that the medium might influence BC´s morphology, but in general, all presented nanofibers, an essential feature in the membrane. Thus, the BC membranes synthesized in this study proved that the BC production using low-cost alternative means is feasible. The material obtained meets the expected thermal, physical, and chemical properties.Keywords: Bacterial cellulose, corn steep liquor, Prodex Lac®, nitrogen sources, carbon sources

Les droits disciplinaires des fonctions publiques : « unification », « harmonisation » ou « distanciation ». A propos de la loi du 26 avril 2016 relative à la déontologie et aux droits et obligations des fonctionnaires

The production of tt‾ , W+bb‾ and W+cc‾ is studied in the forward region of proton–proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98±0.02 fb−1 . The W bosons are reconstructed in the decays W→ℓν , where ℓ denotes muon or electron, while the b and c quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions.The production of $t\overline{t}$, $W+b\overline{b}$ and $W+c\overline{c}$ is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 $\pm$ 0.02 \mbox{fb}^{-1}. The $W$ bosons are reconstructed in the decays $W\rightarrow\ell\nu$, where $\ell$ denotes muon or electron, while the $b$ and $c$ quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions

Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial.

Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited. Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19. Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020. Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (n = 143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (n = 152), or no hydrocortisone (n = 108). Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%). Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (n = 137), shock-dependent (n = 146), and no (n = 101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively. Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions. Trial Registration: ClinicalTrials.gov Identifier: NCT02735707

Measurement of the correlation between the polar angles of leptons from top quark decays in the helicity basis at √s = 7 TeV using the ATLAS detector

A measurement of the correlations between the polar angles of leptons from the decay of pair-produced t and t̄ quarks in the helicity basis is reported, using proton-proton collision data collected by the ATLAS detector at the LHC. The dataset corresponds to an integrated luminosity of 4.6  fb−¹ at a center-of-mass energy of √s = 7  TeV collected during 2011. Candidate events are selected in the dilepton topology with large missing transverse momentum and at least two jets. The angles θ1 and θ2 between the charged leptons and the direction of motion of the parent quarks in the tt̄ rest frame are sensitive to the spin information, and the distribution of cosθ1 ⋅ cosθ2 is sensitive to the spin correlation between the t and t̄ quarks. The distribution is unfolded to parton level and compared to the next-to-leading order prediction. A good agreement is observed

Search for massive, long-lived particles using multitrack displaced vertices or displaced lepton pairs in pp collisions at √s = 8 TeV with the ATLAS detector

Many extensions of the Standard Model posit the existence of heavy particles with long lifetimes. This article presents the results of a search for events containing at least one long-lived particle that decays at a significant distance from its production point into two leptons or into five or more charged particles. This analysis uses a data sample of proton-proton collisions at √s=8  TeV corresponding to an integrated luminosity of 20.3  fb−1 collected in 2012 by the ATLAS detector operating at the Large Hadron Collider. No events are observed in any of the signal regions, and limits are set on model parameters within supersymmetric scenarios involving R-parity violation, split supersymmetry, and gauge mediation. In some of the search channels, the trigger and search strategy are based only on the decay products of individual long-lived particles, irrespective of the rest of the event. In these cases, the provided limits can easily be reinterpreted in different scenarios