Browsing by Issue Date, starting with "2022-01"
Now showing 1 - 10 of 10
Results Per Page
Sort Options
- Production of Hemicellulosic Sugars from Residual Lignocellulosic Biomass in an Integrated Small-Scale Biorefinery: Techno-Economic and Life Cycle AssessmentsPublication . Lopes, Tiago; Duarte, Luís C.; Carvalheiro, Florbela; Cardona, Carlos A.; Gírio, FranciscoABSTRACT: Biorefineries design, as for other industries, usually target the economy of scale approach, maximizing processing capacities to achieve economic viability. However, the installation of large-scale biorefineries has some drawbacks, namely their high capital costs and the difficulty to assure a proper supply of biomass at regional level. Small-scale, self-sustainable, biorefineries can solve several of the challenges of their larger competitors and are also reported to expand environmental and social benefits, but several hurdles for their deployment still exist. This chapter describes a methodology for the implementation of an integrated small-scale self-sustainable biorefinery in a rural area, based on a design that takes advantage of the synergies of processing two types of feedstock (corn stover and swine manure). A detailed explanation for the process selection by performing a heuristic analysis, process simulation, mass and energy balances alongside with the techno-economic assessment of the biorefinery is provided. The full life cycle assessment (LCA) of producing xylo-oligosaccharides (XOS) and ethanol from lignocellulosic residues, i.e. corn stover, under a biorefinery concept to be located in Portugal is also assessed.
- D-lactic acid production from hydrothermally pretreated, alkali delignified and enzymatically saccharified rockrose with the metabolic engineered Escherichia coli strain JU15Publication . Fernandes, M. C.; Alves Ferreira Caturra, Júnia Aparecida; Duarte, Luís C.; Pereira, Helena; Carvalheiro, Florbela; Martinez, AlfredoABSTRACT: Rockrose lignocellulosic residues (RR) were selectively fractionated for hemicellulose separation using autohydrolysis, followed by an alkaline treatment to solubilize the lignin. The cellulose-enriched solids were used to study the effect of solid loading (SL: 2-10%) and enzyme dosage (ED: 6.34-23.66 FPU/g dry biomass) on saccharification using a Doehlert experimental design, followed by fermentation with the metabolic engineered Escherichia coli strain JU15 to produce D-lactic acid (DLA). Pretreatment increased glucan content and enzymatic digestibility up to 84%. A significant positive effect of SL and ED was found for glucose production, but SL negatively impacted glucose yield. DLA concentrations and productivity varied from 8.85 to 32.98 g/L and 1.11 to 2.17 g/(Lh), respectively. Overall process efficiency strongly depended on saccharification yield and varied from 33 to 71%. These results indicate that sequential autohydrolysis, delignification, and fermentation of RR may be a potential relevant strategy for D-lactic production in the biorefinery framework.
- Mortars from the Palace of Knossos in Crete, Greece: A Multi-Analytical ApproachPublication . Carvalho, Fernanda; Sousa, Pedro; Leal, Nuno; Simão, J.; Kavoulaki, Elissavet; Lima, M.M.R.A.; Silva, Teresa; Águas, Hugo; Padeletti, GiuseppinaABSTRACT: The study of building materials constituting cultural heritage is fundamental to understand their characteristics and predict their behavior. When considering materials from archaeological sites, their characterization can provide not only relevant information for a broader understanding of the site and its importance and significance but can also increase knowledge about ancient materials and their performance. The Palace of Knossos is a very important archaeological site in the European history context, and its preservation benefits from the characterization of the constituent materials. Samples of mortars from this monument were collected under the scope of the H2020 HERACLES project, where a multi-analytical approach was chosen using established protocols for the different sample typologies. Instrumental techniques such as optical microscopy (OM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and simultaneous thermogravimetry and differential thermal analysis (TG-DTA) were used for the chemical, mineralogical, and morphological characterization of these mortar samples. The results indicate that the majority are lime mortars, both aerial and hydraulic, but gypsum-based mortars were also identified. Differences in the chemical composition of the samples in distinct areas of the monument allowed us to reflect on the variety of materials used in the construction of the Palace of Knossos.
- Strategies for Efficient Expression of Heterologous Monosaccharide Transporters in Saccharomyces cerevisiaePublication . Knychala, Marília; Santos, Angela A. dos; Kretzer, Leonardo; Gelsleichter, Fernanda; Leandro, Maria José; Fonseca, César; Stambuk, BorisABSTRACT: In previous work, we developed a Saccharomyces cerevisiae strain (DLG-K1) lacking the main monosaccharide transporters (hxt-null) and displaying high xylose reductase, xylitol dehydrogenase and xylulokinase activities. This strain proved to be a useful chassis strain to study new glucose/xylose transporters, as SsXUT1 from Scheffersomyces stipitis. Proteins with high amino acid sequence similarity (78-80%) to SsXUT1 were identified from Spathaspora passalidarum and Spathaspora arborariae genomes. The characterization of these putative transporter genes (SpXUT1 and SaXUT1, respectively) was performed in the same chassis strain. Surprisingly, the cloned genes could not restore the ability to grow in several monosaccharides tested (including glucose and xylose), but after being grown in maltose, the uptake of C-14-glucose and C-14-xylose was detected. While SsXUT1 lacks lysine residues with high ubiquitinylation potential in its N-terminal domain and displays only one in its C-terminal domain, both SpXUT1 and SaXUT1 transporters have several such residues in their C-terminal domains. A truncated version of SpXUT1 gene, deprived of the respective 3 '-end, was cloned in DLG-K1 and allowed growth and fermentation in glucose or xylose. In another approach, two arrestins known to be involved in the ubiquitinylation and endocytosis of sugar transporters (ROD1 and ROG3) were knocked out, but only the rog3 mutant allowed a significant improvement of growth and fermentation in glucose when either of the XUT permeases were expressed. Therefore, for the efficient heterologous expression of monosaccharide (e.g., glucose/xylose) transporters in S. cerevisiae, we propose either the removal of lysines involved in ubiquitinylation and endocytosis or the use of chassis strains hampered in the specific mechanism of membrane protein turnover.
- Surface modification of 5083 aluminum-magnesium induced by marine microorganismsPublication . Jaume, Julien; Marques, Maria João; Délia, Marie-Line; Basseguy, RegineABSTRACT: The influence of microorganisms from a salt marsh in the surface modification of 5083 aluminum alloy (Al-Mg) in seawater was evaluated. An immersion test performed for 50 days in biotic and abiotic conditions, with electrochemical monitoring and surface/cross-section characterization by SEM/EDX and TEM after exposure, showed that microorganisms induced the formation of a homogenous layer on the Al-Mg surface. This layer, which proved to be composed of a doublestructure: a dense, amorphous inner layer and a more porous outer layer, was demonstrated to influence the corrosion resistance of the Al-Mg alloy in seawater.
- How sensitive is a carbon-neutral power sector to climate change? The interplay between hydro, solar and wind for PortugalPublication . Fortes, Patricia; Simoes, Sofia; Amorim, Filipa; Siggini, Gildas; Sessa, Valentina; Saint-Drenan, Yves-Marie; Carvalho, Silvia; Mujtaba, Babar; Diogo, Paulo; Assoumou, EdiABSTRACT: Climate change will impact renewable resources and electricity demand, usually not jointly considered when designing future decarbonized power systems. This paper assesses how sensitive the Portuguese carbon-neutral power sector is to climate change by 2050 and what are the implications for the formally approved Portuguese Carbon Neutrality Roadmap. The future capacity factors for wind, solar and hydropower and electricity demand response to temperature are estimated for 22 climate projections along the Representative Concentration Pathway 4.5 and 8.5. The eTIMES_PT optimization model is used to assess its combined impact on the cost-optimal configuration of the power sector by 2050. Results show that climate change lowers hydropower generation by 20% (in median terms). Improving spatial and temporal resolution and including future climate patterns, results also in lower cost-effectiveness of solar photovoltaic vis-a-vis the Carbon Neutrality Roadmap. While future climate does not impact onshore wind production, offshore wind power generation is positively affected, being a climate-resilient carbon-neutral option for Portugal. Annual electricity unitary costs at final users (excluding taxes and levies) only increase up to 4% with climate change, but seasonal costs have higher variability. This analysis highlights that climate change affects the cost-optimal annual carbon-neutral power sector and needs to be included in energy planning.
- Remanescências do Império Português em África. As amostras geológicas de Capelo e Ivens revisitadas (1884-1885)Publication . Brandão, José Manuel Moraes Vale; Soares, S.; Brito, StelaRESUMO: No presente artigo, revisita-se a coleção de amostras geológicas recolhidas pelos oficiais da Marinha Portuguesa Hermenegildo Capelo e Roberto Ivens, durante a famosa viagem De Angola á Contracosta. Confiadas à Comissão dos Trabalhos Geológicos, aquando do regresso dos exploradores, as amostras foram classificadas por Nery Delgado e Alfredo Bensaúde, tendo sido incorporadas no acervo do Museu Geológico e, na década de 1990, transferidas para a Litoteca do LNEG, polo de Alfragide, onde foram objeto de um trabalho de reacondicionamento e inventário, revisto e ampliado recentemente. Para além do seu valor enquanto testemunho das explorações científicas empreendidas pelos portugueses em solo africano, estas amostras, analisadas em conjunto com o texto homónimo assinado pelos dois exploradores, ilustram muitas das diferentes litologias atravessadas, dos cratões africanos e das orlas sedimentares.
- Assessment of chloride natural background levels by applying statistical approaches. Analyses of European coastal aquifers in different environmentsPublication . Pulido-Velazquez, D.; Baena-Ruiz, L.; Fernandes, Judite; Arnó, Georgina; Hinsby, Klaus; Voutchkova, D. D.; Hansen, B.; Retike, I.; Bikse, J.; Collados-Lara, A. J.; Camps, V.; Morel, I.; Grima-Olmedo, J.; Luque-Espinar, J. A.ABSTRACT: Estimated natural background levels (NBLs) are needed to assess groundwater chemical status according to the EU Groundwater Directive. They are commonly derived for different substances by applying statistical methodologies. Due to the complexity of the sea water intrusion process, some of those methods do not always provide appropriate assessment of chloride NBLs. This paper analyzes the applicability of different NBL estimation methods in five EU coastal aquifers with significant differences in available datasets and hydrogeological set-tings. A sensitivity analysis of results to different constraints was performed to remove samples with anthro-pogenic impacts. A novel statistical approach combining different methods to identify the range of chloride NBLs is proposed. In all pilots the estimated NBLs were below 85 mg/L and fitted well with previous studies and expert judgment, except Campina del Faro aquifer (the maximum being 167.5 mg/L). Although this approach is more time consuming, it provides a more robust solution.
- Nannochloropsis oceanica harvested using electrocoagulation with alternative electrodes: an innovative approach on potential biomass applicationsPublication . Figueiredo, Daniel; Ferreira, Alice; Quelhas, P.; Schulze, Peter; Gouveia, LuisaABSTRACT: Electrocoagulation is a promising technology to harvest microalgal biomass. However, the commonly used aluminum electrodes release undesired salts that decrease biomass value. In this study, alternative iron, zinc, and magnesium electrodes and operational parameters pH, time and current density were studied to harvest Nannochloropsis oceanica. For recovery efficiency and concentration factor the initial pH was most important using iron electrodes, while time and current density were more relevant using zinc and magnesium electrodes. Optimal parameters resulted in biomass recovery efficiencies > 95%, biomass was concentrated 2.8-7.2 times and contained 15.7-29.1% ashes. Elemental analysis revealed metal salts in harvested biomass resulting from electrode corrosion. Finally, ash contents could be reduced by 65% using EDTA as a chelating agent. The electrocoagulation harvested microalgal biomass enriched in essential metals may be a promising bioresource for agricultural growth inducers, or functional ingredients for feed.
- Palynological report of Sesmarias and Caveira DrillingPublication . Pereira, Zélia; Mendes, Márcia