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  1. 1

    Potential of Phaeodactylum tricornutum for Biodiesel Production under Natural Conditions in Chile

    Publicação
    por Branco-Vieira, Monique
    Outros Autores: San Martin, Sergio; Agurto, Cristian; Santos, Marco; Freitas, Marcos; Mata, Teresa et al.
    Diatoms are very diverse and highly productive organisms, found in a wide variety ofenvironments. This study aims to analyze the growth and lipid composition ofPhaeodactylum tricornutum,cultured in an outdoor pilot-scale bubble column photobioreactor under natural conditions in Chile forbiodiesel production.Results showed thatP. tricornutumcultures reached their highest biomassconcentration (0.96±0.04 kg m−3) after 14 days of culturing, at the stationary phase, with avolumetric productivity of 0.13 kg m−3d−1. Biomass samples showed a total lipid content of9.08±0.38 wt %. The fatty acid methyl ester analysis revealed a composition of 24.39% C16-C18 fattyacids, 42.34% saturated fatty acids, 21.91% monounsaturated fatty acids and 31.41% polyunsaturatedfatty acids. These findings suggest thatP. tricornutumoil can be used as an alternative raw materialfor the production of biodiesel capable of meeting international quality standards.
    2017 artigo Portugal acesso aberto
  2. 2

    A life cycle inventory of microalgae-based biofuels production in an industrial plant concept

    Publicação
    por Branco-Vieira, M.
    Outros Autores: Costa, D.; Mata, T.M.; Martins, A.A.; Freitas, M.A.V.; Caetano, Nídia
    Microalgae have been reported as a promising alternative for biofuels production. However, the use of microalgae for biofuels is still a challenge due to the intense energy use and the generation of a significant amount of biomass residues in the process. In order to analyze the environmental impacts of different technological processes for the production of biodiesel from microalgae, several studies have been published making use of the Life Cycle Assessment (LCA) methodology, which allows the recognition of the process bottlenecks and supports the identification of alternatives for a more efficient use of the feedstock. Therefore, in this study, a Life Cycle Inventory (LCI) is compiled, based on real pilot-scale process data, which was scaled-up to a microalgae biomass industrial plant for biofuel production. Values of energy, nutrients, water, and materials consumption are used to create an inventory of inputs and outputs for biomass cultivation and biodiesel production, in order to acquire data to conduct a complete LCA modeling in future studies. According to this model, to produce 1 kg of biodiesel it is necessary about 12 kg of dried algae biomass. This study supports the decision-making process in biofuel production to promote the development of sustainable pilot and large-scale algae-based industry, through the identification of critical factors.
    2020 artigo Portugal acesso aberto
  3. 3

    A life cycle inventory of microalgae-based biofuels production in an industrial plant concept

    Publicação
    por Branco-Vieira, M.
    Outros Autores: Costa, D.; Mata, T.M.; Martins, A.A.; Freitas, M.A.V.; Caetano, Nídia
    Microalgae have been reported as a promising alternative for biofuels production. However, the use of microalgae for biofuels is still a challenge due to the intense energy use and the generation of a significant amount of biomass residues in the process. In order to analyze the environmental impacts of different technological processes for the production of biodiesel from microalgae, several studies have been published making use of the Life Cycle Assessment (LCA) methodology, which allows the recognition of the process bottlenecks and supports the identification of alternatives for a more efficient use of the feedstock. Therefore, in this study, a Life Cycle Inventory (LCI) is compiled, based on real pilot-scale process data, which was scaled-up to a microalgae biomass industrial plant for biofuel production. Values of energy, nutrients, water, and materials consumption are used to create an inventory of inputs and outputs for biomass cultivation and biodiesel production, in order to acquire data to conduct a complete LCA modeling in future studies. According to this model, to produce 1 kg of biodiesel it is necessary about 12 kg of dried algae biomass. This study supports the decision-making process in biofuel production to promote the development of sustainable pilot and large-scale algae-based industry, through the identification of critical factors.
    2019 documento de conferência Portugal acesso aberto
  4. 4

    Association between Elevated Iodine Intake and IQ among School Children in Portugal

    Publicação
    por Carvalho, Irene P.
    Outros Autores: Peixoto, Bruno; Caldas, José Carlos; Costa, Ana; Silva, Sofia; Moreira, Bárbara et al.
    The goal of this work was to examine whether elevated iodine intake was associated with adverse effects on IQ among school-age children in Portugal. In a representative sample of children from the north of the country, IQ percentiles by age (assessed with Raven’s Colored Progressive Matrices) were dichotomized to <50 (“below-average” IQs) and ≥50. Morning urine iodine concentrations, corrected for creatinine, were dichotomized to <250 µg/g and ≥250 µg/g, according to the European Commission/Scientific Committee on Food’s tolerable upper level of daily iodine intake for young children. Data were examined with Chi-square tests, logistic regression, and GLM univariate analysis. The sample (N = 1965) was classified as generally iodine-adequate (median urinary iodine concentration = 129 µg/L; median iodine-to-creatinine ratio = 126 µg/g) according to the WHO’s criteria. A greater proportion of children in the ≥250 µg/g group had below-average IQs, compared to children with less than 250 µg/g (p = 0.037), despite a sizable (though non-significant) proportion of children in the less-than-250 µg/g group also presenting below-average IQs, at the bottom of the iodine distribution (<50 µg/g). The proportion of below-average IQs increased with increasingly elevated iodine concentrations (p = 0.047). The association remained significant after the adjustment for confounders, with the elevated iodine group showing increased odds of having below-average IQs when compared with the non-elevated iodine group (OR 1.55; 95% CI 1.11–2.17; p = 0.011). Consistently, the former group presented a lower mean IQ than the latter (p = 0.006). High iodine intake was associated with lower IQs even in a population classified as iodine-adequate. These results bear on child cognition and on initiatives involving iodine supplementation
    2022 artigo Portugal acesso aberto
  5. 5

    Catalytic bi-reforming of methane for carbon dioxide ennoblement

    Publicação
    por Cunha, Adelino F.
    Outros Autores: Mata, T.M.; Caetano, Nídia; Martins, A.A.; Loureiro, J.M.
    New processes that may reduce the net carbon emissions and contribute to a more circular economy are needed. Bi-reforming of methane (BRM) is a promising method for syngas production, with a hydrogen-to-carbon monoxide ratio of two in the reaction products, relevant for example when the purpose is methanol synthesis. In this work, reaction studies were carried out over a nickel-based catalyst varying the temperature (798–1123 K). Three main temperature zones have been identified; a low temperature zone where the conversion of carbon dioxide is almost null, a middle temperature range where steam reforming of methane (SRM) is dominant while the conversion of carbon dioxide via dry reforming of methane (DRM) is low, and finally a high temperature range where DRM becomes more significant. The results show that syngas can be successfully produced using this process. For the range of operating conditions studied, the carbon dioxide and methane conversions increase with temperature, reaching 40% and 100%, respectively at the largest temperature studied. However, the production of syngas in a molar ratio of 1:2 for CO-to-H requires the use of high temperatures. Most probably the nickel agglomerates on top of the -alumina support are responsible for the poor catalyst performance.
    2019 documento de conferência Portugal acesso aberto
  6. 6

    Evaluation of Areca palm renewable options to replace disposable plastic containers using life cycle assessment methodology

    Publicação
    por Gautam, Anirudh
    Outros Autores: Mata, Teresa M.; Martins, António A.; Caetano, Nídia
    In spite of raising awareness of the environmental impacts associated to the production and utilization of plastics, in many situations, the use of plastics is advantageous, and options are still unavailable or under development, representing an opportunity to develop more sustainable options, such as less energy intensive solutions. In this work, the LCA methodology is used to evaluate the environmental impacts of boxes, bowls and plates produced using Areca palm (Areca catechu) sheath, a waste material common in southern India. The inventory is a combination of primary data from a company in India, complemented with secondary data from the Ecoinvent v2.1 (Simapro V7.3). Results show that the main contributors to the potential environmental impact categories and the most energy intensive life cycle steps, are transportation, shipping and electricity generation. Carbon footprints of 1180, 1033 and 1090 kg CO2eq/ton were obtained for Areca boxes, plates and bowls, respectively. Plates made from Areca palm sheath have lower environmental impacts than plastic plates, except in the ozone layer depletion and terrestrial toxicity impact categories.
    2019 documento de conferência Portugal acesso aberto
  7. 7

    Sustainability evaluation of a Portuguese “terroir” wine

    Publicação
    por Martins, A.A.
    Outros Autores: Costa, M.C.; Araújo, A.R.; Morgado, A.; Pereira, J.M.; Fontes, N. et al.
    The challenges of sustainability are transversal to all human activities, and the wine sector has its own role to play in the march for a more sustainable development. The proper definition of the most adequate measures and/or policies must be based on an objective and quantitative evaluation of the sustainability of a product or process. In this work the sustainability of a “terroir” wine is assessed taking into account its life cycle and using the following indicators: carbon and water footprint, material intensity, solid waste generated, worker turnover rate, investment in H&S training and EBITDA. All indicators are expressed per functional unit of 0.75 L of wine. The evaluation used data from the company complemented with data/information from the literature or life cycle inventory databases. To account for climatic variability, data from three consecutive years was used. Average values of 3.51 kgCO2eq and 481.4 L per functional unit were obtained for the carbon and water footprint respectively, both values within the range of values reported in the literature.
    2019 documento de conferência Portugal acesso aberto
  8. 8

    Gestational Weight Gain and Offspring Bone Mass: Different Associations in Healthy Weight Versus Overweight Women

    Publicação
    por Monjardino, Teresa
    Outros Autores: Henriques, Ana; Moreira, Carla; Rodrigues, Teresa; Adubeiro, Nuno; Nogueira, Luísa et al.
    Weight management strategies during pregnancy reduce child cardiometabolic risk. However, because maternal weight has an overall positive correlation with offspring bone mass, pregnancy weight management could adversely affect child bone health. We aimed to estimate associations between gestational weight gain (GWG) and bone mineralization in the offspring at 7 years of age, and test early pregnancy body mass index (BMI) as an effect modifier. We analyzed prospective data from 2167 mother-child pairs from the Generation XXI birth cohort who underwent whole-body dual-energy X-ray absorptiometry at 7 years of age. GWG was analyzed as a continuous measure and using the Institute of Medicine categories. In the whole sample and for each early pregnancy BMI category (under/normal weight and overweight/obese), relationships between GWG and offspring bone measures (bone mineral content [BMC], bone areal density [aBMD], size-corrected BMC [scBMC], and height) at 7 years were fitted through local polynomial regression and smoothing splines. The magnitude of associations was estimated through linear regression coefficients (95% CIs), crude and adjusted for maternal age, height, educational level, and child gestational age. In under/normal weight mothers, GWG was associated with slightly increased bone measures at 7 years (per 5 kg of GWG, BMC: 0.07 SD [95% CI, 0.01 to 0.12]; aBMD: 0.10 SD [95% CI, 0.05 to 0.15], scBMC: 0.11SD [95% CI, 0.06 to 0.16], and height: 0.05 SD [95% CI, 0.00 to 0.10]), while in overweight/obese mothers no effect of GWG on bone was observed (BMC: 0.02 SD [95% CI, -0.04 to 0.09]; aBMD: 0.02 SD [95% CI, -0.04 to 0.08], scBMC: 0.01 SD [95% CI, -0.06 to 0.08], and height: 0.02 SD [95% CI, -0.04 to 0.08]). Also, no advantageous effect of gaining weight above the Institute of Medicine recommendations was observed in either early pregnancy BMI group. Our results suggest that adherence to Institute of Medicine recommendations for pregnancy weight gain is unlikely to have a negative repercussion on offspring bone health, particularly in women with excess weight in early pregnancy.
    2019 artigo Portugal acesso aberto
  9. 9

    Flocculation of Arthrospira maxima for improved harvesting

    Publicação
    por Caetano, Nídia
    Outros Autores: Martins, A.A.; Gorgich, M.; Gutiérrez, D.M.; Ribeiro, T.J.; Mata, T.M.
    The environmental impacts associated with the burning of fossil fuels coupled with growing concerns about security of energy supply, motivated the search for more sustainable forms of energy production, among which came microalgae for biofuels production. However, the commercial production of microalgae biofuels is still not competitive compared to fossil fuels, as it is necessary to solve some process bottlenecks, among which biomass harvesting, that is the focus of this work. Hence, this work intends to study the harvesting of microalga Arthrospira maxima through flocculation by pH variation and/or addition of CaCl2 as flocculant. Thus, it is described the effect of pH variation (in the range 6 to 12), followed by the addition of flocculant, on the harvesting efficiency. Results show that by pH increase over 10 using NaOH, or by flocculation using CaCl2 at a concentration of 0.2-2.0 g/L and at a 1:30 ratio (v/v) of CaCl2/microalgae culture, it is possible to effectively harvest this microalga.
    2019 documento de conferência Portugal acesso aberto
  10. 10

    Comparison of different lipid extraction procedures applied to three microalgal species

    Publicação
    por Gorgich, M.
    Outros Autores: Mata, T.M.; Martins, A.A.; Branco-Vieira, M.; Caetano, Nídia
    The increase in the world’s energy demand has contributed to the emergence of new sustainable energy sources, such as microalgae, with their great potential to provide biofuels and other high value co-products for the food and health’s markets. However, current biorefinery methodologies are either too complex to extract the targeted components such as high-value products, or require solvents with toxicity for humans and the environment. This work aims to evaluate different lipid extraction approaches applied to three microalgal species: Chlorella zofingiensis, Phaeodactylum tricornutum, and Arthrospira platensis, while employing less toxic and more economical solvents for the lipids extraction. Experimental results showed a promising outcome to tune current biorefinery methodologies, enhancing product yield as well as decreasing potential hazards.
    2019 documento de conferência Portugal acesso aberto