Browsing by Issue Date, starting with "2025-06"
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- Production of sustainable aviation fuel precursors using the oleaginous yeast Rhodotorula toruloides PYCC 5615 cultivated on eucalyptus bark hydrolysatePublication . Saraiva Lopes da Silva, Maria Teresa; Dutra, Francisca; Gomes, Miguel; Costa, Paula; Paradela, Filipe; Ferreira, Frederico Castelo; Torres Faria, Nuno Ricardo; Mugica, Paula; Pinheiro, Helena M.; Sá-Correia, Isabel; Gírio, Francisco; Marques, SusanaABSTRACT: Sustainable aviation fuels (SAF) obtained from renewable sources of carbon can reduce carbon dioxide emissions and contribute for mitigating climate changes. In the present study, the yeast Rhodotorula toruloides PYCC 5615 was found to be highly promising for the bioconversion of eucalyptus bark hydrolysate and the accumulation of intracellular lipids which were further thermochemically processed to bioenergy intermediaries for SAF production. Two growth medium formulations were tested. Eucalyptus bark hydrolysate, obtained by steam explosion followed by enzymatic hydrolysis, was supplemented with yeast nitrogen base medium or with corn steep liquor and mineral medium. The latter produced the highest fatty acid content and productivity (30 % w/w and 0.11 g/ (L.h) respectively). Thereafter, the whole yeast biomass (WB) and the de-oiled biomass (DOB), obtained after lipid extraction, were processed into Bio-crude using a hydrothermal liquefaction (HTL) reactor, with a yield of approximate to 40 % (w/w). The two obtained Bio-crude fractions and the yeast lipids fraction (YL) were further upgraded by hydrodeoxygenation (HDO), to remove oxygen atoms and increase the hydrocarbon content, resulting in a Bio-crude composed of linear long-chain fatty acids suitable for processing to SAF. The best Bio-crude characteristics was observed for WB and YL fractions, with 34.8 % and 40.7 % of hydrocarbons, respectively. Both WB and YL hydrocarbons were composed of C15-C17 compounds. These results demonstrate the potential of an integrated process based on microbial oils from R. toruloides PYCC 5615 to produce SAF precursors from Eucalyptus bark residues, contributing for the sustainable jetfuel bioproduction process.
- Portugal Offshore Wind, Green Hydrogen, and Sustainable Fuels: Power-to-X PathwaysPublication . Simoes, Sofia; Portillo, Juan C. C.; Simões, Teresa; Estanqueiro, Ana; Catarino, Justina; Costa, Paula; Oliveira, Paula; Ribeiro Pinto, Paulo Jorge; Lopes, Fernando; Lopes, Tiago; Gano, António; Duarte de Castro Fontes, Maria MargaridaABSTRACT: Portugal has a vast coastal area and significant offshore wind resources. The country has set ambitious targets and designated specific areas for offshore wind development. Current national policies are actively encouraging investment in these projects. This report compiles the latest strategies for offshore wind and green hydrogen in Portugal. It introduces the Power-to-X (P2X) concept, explores potential offshore wind-based P2X business models, and outlines the key processes and technologies involved. It also maps potential consumers of green hydrogen, along with the associated supply chains for hydrogen and sustainable fuels. A techno-economic analysis was conducted to identify viable pathways for Portugal. This involved selecting one of the planned offshore wind zones and, based on its location and potential capacity, determining the optimal onshore site and scale for a hydrogen and sustainable fuels hub. The report presents a comparative evaluation of seven scenarios, offering valuable insights for both public and private sector stakeholders.
- Bridging gaps in biorefineries: The unexplored role of social dimension in life cycle assessment researchPublication . Ortigueira, Joana; Lopes, TiagoABSTRACT: This review examines the disregarded role of social dimensions in Life Cycle Assessment (LCA) within biorefinery implementation, addressing the question: "How can the inclusion of social factors in LCA improve sustainability assessments, and what are the implications of the limited Social Life Cycle Assessment (S-LCA) studies in biorefineries?" A systematic literature review was conducted using Web of ScienceTM, focusing on studies that integrate social dimensions in LCA. Bibliometric analysis using the bibliometrix R-package and VOSviewer identified key trends, influential papers, and research gaps. Results revealed a significant gap in incorporating social dimensions into biorefinery LCA, with most studies focusing primarily on environmental and economic impacts. Limited attention is given to social aspects such as community well-being, labor rights, and social equity. Case studies that included social factors demonstrated a more comprehensive sustainability assessment, emphasizing the importance of stakeholder engagement and social acceptability in biorefinery projects. This review highlights the need for standardized social indicators and methodologies to integrate social dimensions effectively. The lack of S-LCA in biorefinery implementation reflects a critical gap in sustainability assessments. Addressing this requires developing a unified S-LCA methodology, fostering interdisciplinary collaboration, and encouraging stakeholder participation to ensure diverse perspectives are considered. Ultimately, incorporating social dimensions is essential for achieving a more balanced and comprehensive evaluation of biorefinery sustainability.
- New proton exchange membranes based on ionic liquid doped chitosanPublication . Naffati, Naima; Teixeira, Fatima; Teixeira, António Paulo Silva; Rangel, Carmen M.ABSTRACT: The development of new proton exchange membranes (PEM) for electrochemical devices have attracted researcher's attention in the pursuit for more sustainable and cost-effective technologies for clean energy production and conversion. In this work, new doped chitosan (CS) membranes were prepared by the casting method. Chitosan is an abundant, biodegradable and non-toxic material, and as a membrane, a sustainable and cheaper alternative to those perfluorinated and commonly used, such as Nafion. Three different ionic liquids were employed as dopants, ([EMIM][OTf], [EMIM][FSI] and [MIMH][HSO4]), in various concentrations and up to 50 wt% load. The new membranes were characterized by ATR-FTIR, thermogravimetry, using TGA and DSC techniques to assess their thermal properties, and by SEM, to analyse their surface morphology. Proton conduction properties of the new membranes were assessed by Electrochemical Impedance Spectroscopy (EIS). The new doped membranes showed an increase in the proton conduction compared with pristine chitosan membranes. The incorporation of ionic liquids into chitosan membranes improved their proton conductivity and thermal properties, with [EMIM][OTf] and [MIMH][HSO4] showing the most promising results. A 2-fold increment in the proton conduction was generally observed with the increase of the temperature from 30 to 60 degrees C. The best proton conductivity was found at 60 degrees C for the membrane doped with [EMIM][OTf], with a value of 47 mS.cm(-1).
- Depositional environment and redox conditions of the Moncorvo Ironstone: Unveiling the evolution of ironstones under Rheic Ocean influencePublication . Urbano, Emilio Evo Magro Correa; Preto Gomes, Maria Elisa; Pinto de Meireles, Carlos Augusto; Brandão, Paulo Roberto Gomes; Hippertt, Joa Pedro T.M.; Scholz, Ricardo; Lana, CristianoABSTRACT: Ironstones, as key archives of past marine environments, provide invaluable insights into Paleozoic history. Their mineralogy may reflect the physical-chemical conditions of the environment and the nature of available sediments. This study focuses on the Moncorvo Ironstone, a Lower-Middle Ordovician deposit formed during the opening of the Rheic Ocean. Here, we use an integrated approach combining sedimentology, petrology, and geochemistry to constrain the depositional settings and the redox landscape associated with the ironstone deposition. The Moncorvo Ironstone present some unusual characteristics, such as the lack of ooids, an uncommon mineralogy, and a stratigraphic thickness that can reach over >45 m, a remarkable feature for an ironstone. Our investigation reveals that this iron-rich sequence is distributed in two distinct marine environments: an inner shelf and a middle to distal shelf. Each environment has a unique mineral assemblage. Despite the influence of metamorphism and deformation, evidence suggests that much of the mineralogy and texture of this deposit still preserve characteristics of the original sediments. Finally, our findings, alongside a careful assessment of the mineralogy of other ironstones of similar age, suggest a strong stratification of the Rheic Ocean throughout the Early and Middle Ordovician.
- Bio-oil from hydrothermal liquefaction of microalgae cultivated in wastewater: An economic and life cycle approachPublication . Silva, Thiago; Junior, Maurino Magno de Jesus; Magalhães, Iara; Ananias, Marina Stefany; Saleme Aona de Paula Pereira, Alexia; Rodrigues, Fábio de Ávila; Delgado dos Reis, Alberto José; Calijuri, Maria LuciaABSTRACT: Although microalgae are a promising sustainable biofuel feedstock, their energy-intensive production and most environmental assessments rarely achieve the desired trade-off between productivity and sustainability. In this context, this study aims to evaluate the economic and environmental feasibility of producing bio-oil via hydrothermal liquefaction (HTL) of wastewater-grown microalgae at an industrial scale. Four scenarios varied production scale and steam source: sugarcane bagasse (SCB) in SC1 and SC3, liquefied petroleum gas (LPG) in SC2 and SC4. Each scenario processed microalgae at 300 degrees C for 30 min. Smaller-scale feedstock (1332.9 kg/h) in SC1 and SC2 produced 34.6 kg/h of bio-oil, while the larger feedstock (85,554.4 kg/h) in SC3 and SC4 yielded 2222.2 kg/h. Microalgae biomass cultivation costs dominated overall expenses (56-75 %). Economic analyses indicated minimum selling prices of 3.82-8.52 USD/kg, exceeding the average literature figure of 1.57 USD/kg. Life Cycle Assessment (LCA) showed SCB reduced fossil resource depletion by 14.97 % compared to LPG but increased emissions of nitrogen oxides, particulates, and toxic compounds, which are manageable via selective catalytic reduction and flue gas desulphurization. Cyclohexane as a solvent elevated human carcinogenic toxicity, greener alternatives could reduce toxicity but may cost more, requiring further cost analysis. Advancing this biorefinery route requires optimization of cultivation and processing costs, adoption of environmentally benign solvents, and implementation of emission control strategies to enable economically feasible and environmentally sustainable bio-oil production.
- Zeolites and associated minerals as indicators of post-magmatic hydrothermal alteration in Mesozoic tholeiitic basalts in Northeastern BrazilPublication . Araujo, Lidyane; Castro Jobim Vilalva, Frederico; Franco de Souza, Raquel; Bustamante, Andres; Souza, LaécioABSTRACT: In northeastern Brazil, tholeiitic basalts and microgabbros from the Rio Ceará-Mirim dike swarm and Serra do Cuó basaltic flow experienced post-magmatic hydrothermal alteration, forming secondary minerals that replaced magmatic phases and filled amygdules. Petrographic, X-ray diffraction, thermogravimetric, and chemical analyses identified laumontite, quartz, and calcite as the dominant amygdule minerals in the Rio Ceará-Mirim dikes, formed at temperatures < 150 °C (Stage II) following an earlier low to moderate-temperature (< 150 – 200 ºC) alteration phase (Stage I). In the Serra do Cuó basalts, polymineralic amygdule formation began with mafic phyllosilicates (from < 150 to ~200 °C, Stage I) and proceeded to Ca-Na zeolites (~250 °C, Stage II). These assemblages reflect fluid composition changes due to primary mineral destabilization by heated meteoric fluids. Results indicate fluid composition, rather than temperature, as the primary control on mineral variability, highlighting the role of host-rock chemistry in hydrothermal alteration.