Evaluation of the greenhouse gas balance in the Eucalyptus globulus sector in Portugal

Este estudio evalúa el balance de gas invernadero en el sector del E. globulus en Portugal. Las eliminaciones y las emisiones de dióxido de carbono (CO2) y el metano (CH4) fueron calculadas a lo largo en todo el sector forestal, incluyendo el ecosistema forestal, el tratamiento industrial de madera y las etapas de empleo y la disposición final de productos forestales. El balance de gas invernadero fue calculado restándose la eliminación de carbono neto a las emisiones de carbono fósil y sumándose las emisiones de carbono como el CH4. El balance global de gas invernadero fue una eliminación neta de carbono que varió entre 401 y 1033 Gg Ceq yr-1, respectivamente con el cambio de reservas y los accesos de flujo atmosférico. La diferencia entre las dos estimaciones es equivalente al carbón exportado en productos de madera y forestales. Tanto productos forestales como forestales eran sumideros de carbono, como sus reservas han estado aumentando. Aproximadamente el 94 % del cambio total de reservas de carbono en el sector era debido al bosque, mientras que el papel era el producto forestal con la contribución principal al aumento de reservas de carbono. Emisiones de carbono de fósil consideradas para el 13 % de las emisiones totales de carbono en el sector y disminuido el retiro neto de carbono por 18 y el 34 %, respectivamente con el flujo atmosférico y los cambio de reservas. El carbón emitido como CH4 tuvo la importancia menor y, por consiguiente, era responsable de una disminución en el retiro neto de carbón de sólo 4 y el 8 %, respectivamente con el flujo atmosférico y los accesos de cambio de reservas.____________________________________This study evaluates the greenhouse gas balance in the E. globulus sector in Portugal. Removals and emissions of carbon dioxide (CO2) and methane (CH4) were calculated along the whole forest sector, including the forest ecosystem, the industrial processing of wood and the stages of use and final disposal of forest products. The greenhouse gas balance was calculated by subtracting to the net carbon removal, the fossil carbon emissions and the additional emissions of carbon as CH4. Two different approaches were applied for estimating the net carbon removal in the sector: the stock-change and the atmospheric-flow approach. The global greenhouse gas balance was a net removal of carbon that varied between 401 and 1033 Gg Ceq yr-1, respectively with the stock-change and the atmospheric-flow approaches. The difference between the two estimates is equivalent to the carbon exported in wood and forest products. Both forest and forest products were carbon sinks, as their stocks have been increasing. About 94% of the total change in carbon stocks in the sector was due to forest, whereas paper was the forest product with the major contribution to the increase of carbon stocks. Fossil carbon emissions accounted for 13% of the total carbon emissions in the sector and decreased the net carbon removal by 18 and 34%, respectively with the atmospheric-flow and the stock-change approaches. Carbon emitted as CH4 was of minor importance and, consequently, was responsible for a decrease in the net carbon removal of only 4 and 8%, respectively with the atmospheric-flow and the stock-change approaches

Heat-shock and titanium dioxide nanoparticles decrease SOD and glutathione enzymes activities in Saccharomyces cerevisiae

It is well-known that the majority of living organisms depend on oxygen for survival. However, organisms also had to evolve a multitude of enzyme antioxidant defences as superoxide dismutase (SOD1, SOD2), glucose-6-phosphate dehydrogenase (G6PD), glutathione reductase (GR), glutathione peroxidase (GPx), and catalases (CTT1, CTA1) as well as non-enzyme defences as glutathione, to protect their cells from toxicity of reactive oxygen species (ROS). Exposure of living organisms to xenobiotic can also induce significant generation of ROS. Failure of cell antioxidant defences to prevent ROS accumulation inevitably results in oxidative stress. This potentially causes severe oxidative damages in vital biomolecules, thus compromising cell viability. Yeasts can provide a significant contribution to our understanding of oxidative stress, and its consequences on cell death, because its cellular structure and functional organization share many similarities with plant and animal cells. Although ROS accumulation in yeast generally results from cell respiration, environmental stress stimuli can be also another important source. Despite the intensive use of engineered nanoparticles (NPs) in various consumer and industrial products, data on their potential hazards are still rare and mechanisms of action only partially understood. In addition, NPs as titanium dioxide nanoparticles (TiO2-NP) possessing unique physicochemical characteristics such as high specific surface area, high reactivity, and rapid diffusion, which differ from bulk materials of the same composition (TiO2). On the other hand, yeast response to ROS (H2O2) or the toxicity of NPs depends on environmental conditions as temperature. Consequently, the aim of this work was to evaluate the antioxidant response of Saccharomyces cerevisiae, grown in presence of glycerol or glycerol and glucose, to 5 μg/mL TiO2-NP in heat-shock conditions

Heat shock and titanium dioxide nanoparticles decrease superoxide dismutase and glutathione enzymes activities in Saccharomyces cerevisiae.

The exposure of living organisms to metals can generate reactive oxygen species and failure in their antioxidant defences, triggering oxidative stress and oxidative damage. Despite the intensive use of engineered nanoparticles in numerous consumer and industrial products, data on their potential hazards in eukaryotic cells and their dependence on environmental factors such as temperature are still scarce. The aim of this study was to evaluate the antioxidant response of Saccharomyces cerevisiae, grown in presence of glycerol and glucose, to 5 μg/ml titanium dioxide nanoparticles (size<100 nm) under heat shock conditions. The results showed that biomass, levels of reactive oxygen species and glutathione reductase activity in respiratory/fermentative cells were higher than those detected in respiratory cells. Furthermore, respiratory/fermentative cells exhibited lower levels of glutathione, malondialdehyde, cytoplasmic catalase and glutathione peroxidase than those detected in the respiratory yeast. Saccharomyces cerevisiae grown in the presence of glycerol, glucose and titanium dioxide nanoparticles, under heat shock conditions, caused oxidative stress, due to a decrease in antioxidant defences such as superoxide dismutases or a slowdown of the glutathione cycle, relative to cells grown in presence of glycerol and glucose

Antioxidant response to titanium dioxide nanoparticles by Saccharomyces cerevisiae grown in different carbon sources and heat-shock conditions

The physicochemical properties that make nanomaterials unique, also equip them with potential for affect environment adversely, causing oxidative injuries in the living beings. However, organisms also had to develop antioxidant defences to protect their cells from reactive oxygen species (ROS). Failure in the cell antioxidant defences, due to the contact with xenobiotic, results in stress causing oxidatives damages leading to loss of cell viability. Yeasts can contribute to understand the toxicity of titanium dioxide nanoparticles (TiO2-NP), because its cell structure and functional organization, share similarities with mammalians. Since the response of yeast to NPs can be influenced by temperature and available carbon source, the aim of this study was to evaluate the antioxidant response of Saccharomyces cerevisiae, grown in presence of glycerol with addition of 2% glucose and 5 g/mlTiO2-NP, in heat-shock conditionsTiO2-NP (size <100 nm) stock suspensions were prepared by sonication. Bioassays were performed in YEPG medium (1% yeast extract, 2% peptone, 3% glycerol). Culture flasks were inoculated with wild-type Saccharomyces cerevisiae UE-ME3 and shaken 150 rpm, at 28°C. At exponential phase was added glucose and TiO2-NP stock solution (YEPGD-NP) to obtain a final concentration of 2% and 5 lg/ml. Yeasts grown 200 min at 28 or 40°C (heat-shock, HS). Flasks lacking glucose (YEPG) or NPs served as controls. Biomass was quantified by dry weight. Post-12000 g supernatants were used for determination of GSH, GSSG and ROS contents by fluorescence as well as glutathione reductase (GR), glutathione peroxidase (GPx), glucose-6-phosphate dehydrogenase (G6PD), catalase (CTT1) activity by spectrophotometry. Post-12000 g pellets were used for determination of catalase (CTA1) activity. Statistical analysis by ANOVA I and Duncan test. The results showed that biomass,ROS level and GR activity in the cells grown in YEPGD were higher than those detected in cells grown in YEPG. Furthermore, cells grown in YEPGD exhibited lower levels of GSH and MDA and CTT1activity comparatively with yeasts grown in YEPG. S. cerevisiae grown in YEPGD-NP in HS showed growth inhibition to levels near of cells which used glycerol as carbon source. Additionally, it was also detected a decrease in the GSH contents, GSH/GSSG ratio, GPx, CTT1 and CTA1 activities as well as an increase in ROS content and GR activeity, relatively to the cells growing only in glycerol. It was also observed an increase in ROS level and GR activity in the yeast grown in YEPGD-NP, relatively to S. cerevisiae grown in YEPGD. TiO2-NP in HS caused oxidative stress in yeast grown in presence of glycerol and glucose, decreasing GSH/GSSG ratio,increasing ROS content and GR activity

Early exposure to titanium dioxide nanoparticles caused a decrease in the cytoplasmic catalase activity, inducing lipid peroxidation in the Saccharomyces cerevisae.

The massive production of nanomaterials has created new pollutants whose interaction with living organisms is unclear. Recent studies have revealed that these materials generate reactive oxygen species, causing cell damage, when antioxidant systems fail, fact which justifies its inclusion in toxicological studies. Thus, the aim of this study was to test if early exposure of Saccharomyces cerevisiae to 5 μg/mL of titanium dioxide nanoparticles (TiO2-NP, size < 100 nm), with heat shock, does not disturb its antioxidant response mediated by superoxide dismutase and catalase activity. S. cerevisiae UE-ME3, a wild-type strain belonging to Oenology Laboratory of the University of Évora were grown in YEPG medium (3% glycerol) at 28 °C. At middle-exponential phase 2% glucose (YEPGD) and/or 5 μg/mL TiO2-NP stock solution were added and cells were grown for 200 min at 28 °C or 40 °C (heat-shock, ST). Culture medium lacking glucose or NPs served as control samples. At the end of the experiment, the dry weight was determined and remaining cells were disintegrated in 10 mM phosphate buffer pH 7.0 by ultra-sonication. The post-12,000 × g supernatant was used for determination of MDA content and catalase (CTT1) and superoxide dismutase (SOD1) activity. The pellet was used for determination of activities catalase (CTA1) and superoxide dismutase (SOD2). The results showed that the presence of glucose in the medium caused an increase of biomass, a decrease in the MDA content and CTT1 activity without change CTA1, SOD1 and SOD2 activity. Additionally, it was determined an increase in CTA1, SOD1 and SOD2 activity in the cells grown in YEPGD-ST medium. The NP-TiO2 exposure with ST, decreased CTT1 activity for similar levels to those estimated in the cells grown in YEPGD medium with nanoparticles, did not affect the CTA1 and SOD1 activity, increased the MDA level and kept the SOD2 activity in similar levels to those detected in cells grown in YEPGD-ST medium. The decrease in the CTT1 activity caused by NPs may justify, in part, the increase in MDA level

Influence of temperature on Saccharomyces cerevisiae UE-ME3 response to titanium dioxide nanoparticles

Titanium dioxide is a polymorphic material which can be found in nature in three mineral phases: rutile, anatase and brookite, the most unstable and of less interest. The form of NP-rutile TiO2 (<100 nm) is described as one of the most toxic compound. While living organisms have been exposed with nanoparticles from millions of years ago and may be adapted to low levels of these materials, the increase of industrial capacity of synthesis, manipulation and massive use in electronic, energy and catalysis processes has increase the environmental levels of nanomaterials in several regions of the planet. The nanotoxicology is an emerging field for research, since fixed mass, density and surface reactivity are features of nanoparticles that contribute for the generation of ROS. The main intention of this work was to determine the influence of temperature and titanium dioxide nanoparticles on the growth of S. cerevisiae UE-ME3, a wine wild-type strain of Alentejo, Portugal

Treatment of dairy wastewater in UASB reactors inoculated with flocculent biomass

This work assesses the possibility of using flocculent sludge in UASB reactors applied to the treatment of dairy wastewater and studies the effect of hydraulic retention time (6, 8, 12 and 16 h) on the performance of the reactors. The results show that the performance of flocculent sludge is similar to what has been reported in literature for granular sludge. It was observed that by raising the HRT from 6 to 12 h the performance of the system is improved concerning the maximum applicable load, the COD removal efficiency and methane production, but by raising the HRT from 12 to 16 h the differences are not meaningful. To attain soluble COD removals, VFA removals and protein mineralisation near 80% and fat removals above 60% it is necessary to operate the UASB reactors at an HRT of at least 12 h. In addition to this the reactors must be operated at loads under 2.5 g COD/&#8467;•d in order to attain a conversion to methane of the removed COD above 70%. Keywords: UASB, hydraulic retention time, optimum load, flocculent biomass, dairy wastewater Water SA Vol. 31(4) 2005: 603-60

Biodegradation kinetics of winery wastewater from Port Wine production

Winery wastewaters are characterised by seasonality and variable volume and organic load. This fact together with their high content of biodegradable compounds often results in problems in the operation of biological systems as they may lead to poor sludge settleability, floc disintegration and increased presence of solids in the treated effluent. Biodegradation of winery wastewater from a Port Wine production industry was studied in aerobic batch assays, varying substrate and biomass concentrations. More than 90 % of COD was removed in all cases, in a short period when biomass concentration was higher than 3 g VSS L–1. Data was correlated to several kinetic models, and Haldane model best fitted the experimental data, particularly for lower biomass concentrations. Therefore, an initial high biomass concentration should be present in aerobic treatment of winery wastewater, in order to cope with the large fluctuations in their organic loads. These batch assays are valuable for winery wastewater treatment, as they may simulate typical start-ups after short and long shutdown periods often observed in the winery industry.publishe

Acidogenic Fermentation Towards Valorisation of Organic Waste Streams into Volatile Fatty Acids

Anaerobic acidification of eight organic streams (cheese whey, sugarcane molasses, organic fraction of municipal solid wastes (OFMSW), glycerol, soapy slurry, winery wastewater, olive mill effluent, and landfill leachate) was evaluated in batch experiments to determine their acidogenic potential and examine the composition of the produced volatile fatty acids (VFA). Cheese whey, molasses and OFMSW presented the highest acidogenic potentials (0.3 to 0.4 gVFA per g of chemical oxygen demand fed, CODfed) with the predominance of acetic, n-butyric and propionic acids. A further experimental set was applied to cheese whey, by varying food-to-microorganism ratio (F/M) and initial alkalinity. Maximisation of VFA production (up to 0.63 gVFA g–1CODfed) was obtained for an initial alkalinity of 5 – 7 g L–1 as CaCO3 and F/M ratios of 2 – 4 gCOD g–1VSS. Moreover, it was demonstrated that low F/M ratios combined with high alkalinity supply can shift the VFA profile by increasing the production of propionic and n-valeric acids. The results are useful towards optimal designs for acidogenic processes based on the composition of the VFA produced, since the control of the acidification products is crucial for valorisation in some applications

Signatures of non-gaussianity in the isocurvature modes of primordial black hole dark matter

Primordial black holes (PBHs) are black holes which may have formed very early on during the radiation dominated era in the early universe. We present here a method by which the large scale perturbations in the density of primordial black holes may be used to place tight constraints on non-gaussianity if PBHs account for dark matter (DM). The presence of local-type non-gaussianity is known to have a significant effect on the abundance of primordial black holes, and modal coupling from the observed CMB scale modes can significantly alter the number density of PBHs that form within different regions of the universe, which appear as DM isocurvature modes. Using the recent \emph{Planck} constraints on isocurvature perturbations, we show that PBHs are excluded as DM candidates for even very small local-type non-gaussianity, $|f_{NL}|\approx0.001$ and remarkably the constraint on $g_{NL}$ is almost as strong. Even small non-gaussianity is excluded if DM is composed of PBHs. If local non-Gaussianity is ever detected on CMB scales, the constraints on the fraction of the universe collapsing into PBHs (which are massive enough to have not yet evaporated) will become much tighter.Comment: 23 pages, 11 figures. V2: minor corrections and changes, matches published versio