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Browsing ENERGIA by Sustainable Development Goals (SDG) "12:Produção e Consumo Sustentáveis"
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- Alternative feedstocks for high-quality biodiesel: Lipid production from eucalyptus bark hydrolysate by Yarrowia lipolytica W29 using different cultivation modesPublication . Dias, Bruna; Lopes, Marlene; Marques, Susana; Gírio, Francisco; Belo, IsabelABSTRACT: Microbial lipids produced by yeasts from lignocellulosic biomass are a promising feedstock for the biodiesel industry, providing a renewable energy source as an alternative to traditional fossil fuels. This study investigated the potential of Yarrowia lipolytica W29 to produce lipid-rich biomass from undetoxified sugar-concentrated eucalyptus bark hydrolysate (EBH). The lipid concentrations achieved in batch cultures (13.4 g L-1) were the highest for wild-type Y. lipolytica strains in lignocellulosic hydrolysates. Different two-stage cultivation modes (repeated batch, continuous-feeding fed-batch, and pulse fed-batch) were studied to enhance biomass and lipid production. The cell and lipid mass was higher in pulse fed-batch and continuous-feeding fed-batch cultures than batch cultures. Production of citric acid, a side product of industrial interest, was improved in the continuous-feeding fed-batch culture. Microbial lipids produced by Y. lipolytica W29 were highly unsaturated and mainly composed of oleic acid (50% to 53%). The estimated properties of the biodiesel that would be obtained from these intracellular lipids would meet the international biodiesel standards EN 14214 and ASTM D6751. This study demonstrates the feasibility of using EBH for Y. lipolytica lipid production and promotes the sustainable production of high-quality biodiesel from lignocellulosic feedstocks.
- 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.
- Biopolymers Derived from Forest Biomass for the Sustainable Textile IndustryPublication . Dias, J. C.; Marques, Susana; Branco, Pedro C.; Rodrigues, Thomas; Torres, Cristiana A.V.; Freitas, Filomena; Evtuguin, Dmitry; Silva, CarlaABSTRACT: In line with environmental awareness movements and social concerns, the textile industry is prioritizing sustainability in its strategic planning, product decisions, and brand initiatives. The use of non-biodegradable materials, obtained from non-renewable sources, contributes heavily to environmental pollution throughout the textile production chain. As sustainable alternatives, considerable efforts are being made to incorporate biodegradable biopolymers derived from residual biomass, with reasonable production costs, to replace or reduce the use of synthetic petrochemical-based polymers. However, the commercial deployment of these biopolymers is dependent on high biomass availability and a cost-effective supply. Residual forest biomass, with lignocellulosic composition and seasonably available at low cost, constitutes an attractive renewable resource that might be used as raw material. Thus, this review aims at carrying out a comprehensive analysis of the existing literature on the use of residual forest biomass as a source of new biomaterials for the textile industry, identifying current gaps or problems. Three specific biopolymers are considered: lignin that is recovered from forest biomass, and the bacterial biopolymers poly(hydroxyalkanoates) (PHAs) and bacterial cellulose (BC), which can be produced from sugar-rich hydrolysates derived from the polysaccharide fractions of forest biomass. Lignin, PHA, and BC can find use in textile applications, for example, to develop fibers or technical textiles, thus replacing the currently used synthetic materials. This approach will considerably contribute to improving the sustainability of the textile industry by reducing the amount of non-biodegradable materials upon disposal of textiles, reducing their environmental impact. Moreover, the integration of residual forest biomass as renewable raw material to produce advanced biomaterials for the textile industry is consistent with the principles of the circular economy and the bioeconomy and offers potential for the development of innovative materials for this industry.
- 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.
- Bridging Regional Divides in Decarbonization: Firm Strategies, Policy Tensions, and Structural Trade-offs in Portugal [Resumo]Publication . Vale, Mário; Alves, Tiago; Fontes, Margarida; Mamede, Ricardo; Bento, NunoABSTRACT: The transition to a low-carbon economy is shaped by structural tensions and trade-offs that impact firms, regions, and policymakers. A central challenge is balancing regional equity, industrial specialization, and technological innovation in decarbonization policies (Markard & Rosenbloom, 2022). This study critically examines these tensions by analysing firm-level decarbonization strategies within the Portugal 2020 (PT2020) program, revealing how economic structures shape sustainability transitions and the effectiveness of policy interventions.
- Clean production of microalgae high-value lipid fraction: Influence of different pretreatments on chemical and cytotoxic profiles of Chlorella vulgaris supercritical extracts and life cycle assessmentPublication . Vladic, Jelena; Radman, Sanja; Jerkovic, Igor; Besu, Irina; Speranza, Lais Galileu; Hala, Ahmad Furqan; Kovacevic, Strahinja; Perreira, Hugo; Gouveia, LuisaABSTRACT: Microalgae have emerged as a promising natural resource rich in bioactive compounds. Health-beneficial properties of microalgae, coupled with advantageous characteristics such as high biomass productivity, adaptability, robustness, and carbon dioxide mitigation, position them as a viable solution for global sustainable food production. This study explored clean and environmentally friendly processes to enhance the recovery of lipid bioactive fractions. Microwave (MW), enzymatic (ENZ), and ultrasound (US) pretreatments were applied to improve environmentally friendly extraction of lipid-based components using supercritical CO2. The effects of these pretreatments on extraction yield, chemical profiles, and cytotoxic properties of Chlorella vulgaris (Cv) and smooth C. vulgaris (sCv) extracts were investigated. Additionally, a Life Cycle Assessment (LCA) was conducted to evaluate environmental impacts. MW pretreatment achieved the highest yield increases, from 2.58 times (Cv) to 3.15 times (sCv). UHPLC-ESI-HRMS analysis revealed shifts in the distribution of pigments and derivatives caused by pretreatments, with ENZ extracts showing the most pronounced changes: pigments increased from 9.24% (control Cv) to 40.92% (Cv) and from 12.52% (control sCv) to 71.12% (sCv). Cv extracts exhibited greater activity against MDA-MB-453 cells, while sCv extracts from US pretreatment demonstrated the strongest effect on HeLa cells. The LCA indicated reduced environmental impacts of the pretreatment-enhanced processes up to 65% compared to the control. A scenario analysis was presented to show further possible impact reduction by recirculating the CO2 solvent and substituting the energy source. These findings provide valuable insights into sustainable and scalable green processes for recovering microalgal bioactive components.
- Comparison of the corrosion of ferritic and austenitic stainless steel (AISI 430 and AISI 316L) with LiNaK carbonate salts for thermal energy storage in CSP/CST applicationsPublication . Gil, Mafalda; Pedrosa, Fátima; Paiva Luís, Teresa; Figueira Vasques, Isabel; Oliveira, Fernando; Cunha Diamantino, TeresaABSTRACT: This study focuses on the corrosion rates and mechanisms of two stainless steels, austenitic AISI 316L and ferritic AISI 430, in contact with a eutectic mixture of LiNaK carbonates in long-term tests at 650 degrees C. The selection of these two stainless steels was based on their differences, both in their intrinsic characteristics and in the cost associated with each one. The research also underscores the importance of optimizing the descaling methods used to evaluate the corrosion rate. Corrosion rates were measured gravimetrically according to ISO 17245:2015, revealing an asymptotic behavior for both steels, with AISI 430 with a corrosion rate of 237 f 21 mu m and AISI 316L of 151 f 13 mu m after 2000 h of testing. Corrosion mechanisms were analyzed using SEM/EDS, GDOES, and XRD techniques, which identified well-defined oxide layers with varying compositions. Given the observed corrosion mechanisms and its lower cost, AISI 430 steel seems to have great applicability in CSP/CST plants, provided it is paired with an appropriate protective coating.
- Consortium of microalgae/nitrogen-fixing bacteria as a next-generation biofertilizer, biostimulant and biopesticidePublication . Gouveia, Luisa; Ferreira, Alice; Bastos, Carolina R. V.; Avetisova, Gayane; Karapetyan, Zh.; Toplaghaltsyan, A.; Melkonyan, LusineABSTRACT: This study aims to provide insights into a new consortium of a microalga, twelve nitrogen-fixing (N-fixing) bacteria and a cyanobacterium. The microalga Tetradesmus obliquus (T), in conjunction with various N-fixing bacteria and the cyanobacterium Synechocystis sp. PCC 6803 (S), the N-fixing bacterium Sphingobacterium sp. L13G8 (5), cultivated in complete Bristol medium and in Bristol-NaNO3 free conditions, were examined. The study encompassed the analysis of their consortia, including evaluation of their growth, and potential as a biostimulant, biofertilizer and biopesticide, and assessed for sedimentation performance for targeted applications. The T and N-fixing bacteria consortia had higher growth in Bristol NaNO3-free media. The triple culture TS5 had the highest growth parameter (2.4 OD540) in the same medium, followed by T5. The consortia were employed to ascertain the efficacy of their biostimulants and biofertilizers on watercress (Lepidium sativum) and to determine the potency of their biopesticides against the fungal pathogens Fusarium oxysporum and Rhizoctonia solani (in certain consortia). Consortium T5 demonstrated the most significant impact on the seeds germination index (212.7%) and root length (6.0 cm) of L. sativum. The same consortium had a significant impact on the shoot length (4.4 cm) of L. sativum. Among all consortia that were examined, T5 exhibited significant inhibitory effects on the growth of F. oxysporum (60.6%) and R. solani (69.2%). In the same consortium, the rate of microalgal biomass sedimentation was enhanced by the N-fixing bacterium (0.4 cm h-1). Consortium T5 was the most effective in relation to growth and biomass sedimentation efficiency, in addition to its use as a biostimulant, biofertilizer and biopesticide. The created combination of microalga and N-fixing bacterium represents significant progress in the field of microalga cultivation, with notable benefits including improved biomass sedimentation and enhanced agricultural practices, as well as environmental friendliness and safety.
- Critical transitions: Unpacking decarbonization strategies in Portuguese industry and regional disparitiesPublication . Vale, Mário; Alves, Tiago; Duarte de Castro Fontes, Maria Margarida; Mamede, Ricardo; Bento, NunoABSTRACT: In the wake of the Paris Agreement, the urgency for decarbonization has intensified globally, prompting varied responses from different regions and sectors. This study critically examines the uneven decarbonization trajectories of Portuguese firms within the framework of the Portugal 2020 (PT2020) program, informed by transition theory and regional innovation systems. Employing a multi-method approach that combines natural language processing and a systematic literature review, we identify and categorize the decarbonization strategies of 278 out of 2,793 firms funded by PT2020 between 2020 and 2023. Our findings reveal a modest (less than 10 % of all projects) but pivotal engagement in decarbonization, predominantly focused on the Porto metropolitan area and adjacent regions, indicating a pattern of uneven geographical transitions. Larger, established firms predominantly undertake these initiatives, reflecting a skew in policy effectiveness towards more stable entities. The most common pathways—demand and co-benefits (49 %) and decarbonization of electricity (34 %)—suggest a preference for immediately actionable strategies (electrification of uses and technological breakthroughs). This study underscores the disparity in decarbonization efforts across firms, but also regions, correlating higher industrial productivity and urbanization with increased activity. Such trends reveal the influence of existing economic structures and regional capacities on the adoption of green technologies, which exacerbate regional inequalities in the face of global decarbonization mandates. This study improves the understanding on the potential of decarbonization to increase or decrease inequalities among companies and regions. It provides crucial lessons for policies aiming to accelerate decarbonization to achieve the 2030 goals. Further research is required to explore the impact of regional specialization on decarbonization strategies and to develop more inclusive and equitable policies.
- Decarbonization Transition Pathways and Regional Trends: Insights from One Million StudiesPublication . Bento, Nuno; Alves, Tiago; Ribeiro, Ricardo; Fontes, MargaridaABSTRACT: As global temperatures near critical thresholds and emissions continue to rise, the urgency for strategic, accelerated decarbonization grows. Despite a vast climate mitigation literature, a systematic understanding of actionable pathways remains limited. Here, we apply artificial intelligence to analyze over one million scientific papers (2011–2021), generating a data-driven typology of six archetypal decarbonization pathways: Technology Breakthrough, Electrification of Uses, Integrated Policy, Decarbonization of Electricity, Demand Reduction & Co-benefits, and Land Use & Circularity. Regional patterns show Electrification of Uses prevailing in Europe (EU27), while Technology Breakthrough dominates in China, the US, and Japan. Increasing political and societal resistance to mitigation makes the strategic selection and combination of pathways even more critical. Our analysis highlights key synergies between pathways, the scientific competencies required to support them, and persistent gaps—particularly in Land Use and Circularity. We also compare current climate policy directions with the typology, revealing alignment gaps that may weaken policy effectiveness. This framework enables policymakers to better match strategies with regional capacities and research strengths, offering a more coherent approach to decarbonization. Strengthening the integration of science, technology, and policy is essential to overcome fragmentation and deliver the emissions reductions needed to meet the net-zero climate targets.