Microbial communities shifts in dark fermentative H2 production at mesophilic, thermophylic and hyperthermophylic conditions

Hydrogen is foreseen as a viable CO2-neutral alternative to fossil fuels for generation of energy. Production of H2 from wastes/wastewaters is possible as this is one of the main products resulting from anaerobic fermentation of organic compounds. If hydrogenotrophic methanogens are suppressed, H2-rich biogas can be recovered from anaerobic reactors. In order to optimize and improve H2 production, it is essential to get more insight into the composition and structure of the microbial communities involved in the process. In this study microbial community shifts in expanded granular sludge blanket (EGSB) reactors producing H2 at different temperatures and organic loading rates (OLR) were studied using PCRDGGE fingerprinting analysis. The aim was to get more insight into the microbiology of dark fermentative hydrogen production at mesophilic, thermophilic and hyperthermophilic temperatures. Three EGSB reactors were inoculated with granular biomass previously treated with heat to suppress methanogens. Reactors were operated at 37, 55 and 70 ºC with 5gCOD L-1of a mixture containing glucose and L-arabinose (1:1); pH was kept at 5.5. OLR applied varied from 5 to 16. PCR amplification of the 16S rRNA gene and subsequent DGGE analysis of sludge samples collected from the reactors at different operational times showed different profiling, mainly correlated with differences in temperature. Bacterial diversity (measured as the number of bands) in sludge samples from reactors operating at 55 ºC and 70ºC was remarkably lower than in sludges growing at 37ºC. No significant changes on DGGE profiles diversity were observed with the increase of OLR over time

Resistência de linhagens genitoras e híbridos simples de sorgo a Colletotrichum sublineolum, agente causal da antracnose.

Foi avaliada a reação de resistência de dez híbrido s simples de sorgo (Sorghum bicolor) e 14 linhagens genitoras destes híbridos ao patógeno Colletotrichum sublineolum, agente causal da antracnose. Em casa de vegetação, os genótipos foram inoculados se paradamente com 20 isolados monospóricos obtidos de diferentes regiões produtoras do país. A avaliação foi realizada aos dez dias após a inoculação, utilizando-se escala de notas. Nenhum genótipo de sorgo foi resistente a todos os isolados inoculados. A linhagem CMSXS657 foi resistente a 95%; a linhagem ATF14, a 90%; ATF08, a 85% e CMSXS210, a 70% dos isolados. Dentre os híbridos, destacou-se o BRS305 (CMSX S210A X BR012R), resistente a 75% dos isolados; 9920045 (ATF14A X CMSXS180R), a 65% dos isolados; BRS308 (CMSXS233A X BR012R), a 60% dos isolados e BRS650 (CMSXS222A X CMSXS657R), a 55% dos isolados. As linhagens BR001 e CMSXS222 foram suscetíveis a 90% dos isolados. A frequência de resistência dos híbridos foi igual ou inferior às linhagens genitoras. Exceção faz-se ao híbrido BRS305 (CMSXS2 10A X BR012R), que foi resistente a um maior número de isolados que seus genitores. Nenhum dos isolados testados foi virulento a todos os genótipos. Os isolados de Campo Novo dos Parecis (MT) foram os mais virulentos enquanto os isolados de Jardinópolis (SP) foram os menos virulentos

Microbial community structure of biohydrogen production process in extreme thermophilic conditions

Fundação para a Ciência e a Tecnologia (FCT

New features of the phase transition to superconducting state in thin films

The Halperin-Lubensky-Ma (HLM) effect of a fluctuation-induced change of the order of phase transition in thin films of type I superconductors with relatively small Ginzburg-Landau number $\kappa$ is considered. Numerical data for the free energy, the order parameter jump, the latent heat, and the specific heat of W, Al and In are presented to reveal the influence of film thickness and material parameters on the properties of the phase transition. We demonstrate for the first time that in contrast to the usual notion the HLM effect occurs in the most distinct way in superconducting films with high critical magnetic field $H_{c0}$ rather than in materials with small $\kappa$. The possibility for an experimental observation of the fluctuation change of the order of superconducting phase transition in superconducting films is discussed.Comment: 11 pages, MikTexTeX, 3 fig, 2 Tables, corrected some typos, Submitted J.Phys:Cond Ma

Extreme thermophilic biohydrogen production from arabinose and glucose

Continuous hydrogen production rate from arabinose was significantly higher than from glucose, when higher organic loading rate was used. This fact was associated to higher lactate production in the reactor fed with glucose. The higher concentration of lactate was not a consequence of bacterial community shift, and is likely related to changes in the main metabolic pathways of glucose catabolism

Teste de condutividade elétrica em sementes de jequitibá-rosa (Cariniana legalis) O. Kuntze.

Resumo

Teste bioquímico em embriões de pinheiro-brasileiro (Araucaria angustifolia) Bert. O. Kuntze.

Resumo

Cortina amarela e azul, programas de luz quase contínuo e intermitente, na produção de frangos de corte.

Projeto/Plano de Ação: 06.06.02.359-02