Browsing by Author "Matos, Cristina T."
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- Biocombustíveis: uma oportunidade ou um problema para PortugalPublication . Gírio, Francisco; Lukasik, Rafal M.; Matos, Cristina T.; Oliveira, Ana Cristina; Silva, LuísApresenta-se nesta curta comunicação a problemática referente à introdução dos biocombustíveis nos transportes em Portugal na sequência da transposição para a legislação nacional das diferentes diretivas europeias (2003 e 2009). A produção de biocombustíveis em território nacional tem vindo a aumentar na sequência da política nacional de promoção dos mesmos embora as matérias-primas utilizadas (oleaginosas) sejam praticamente todas importadas com exceção do uso de matérias residuais. Particular atenção é dedicada aos dois critérios de sustentabilidade obrigatórios para que um dado biocombustível seja considerado “produzido de forma sustentável”, abordando-se ainda a problemática das alterações indiretas do uso da terra (ILUC) na sequência da recente proposta da Comissão Europeia em rever a atual diretiva nesta matéria.
- Carbon footprint assessment of microalgal biomass production, hydrothermal liquefaction and refining to sustainable aviation fuel (SAF) in mainland PortugalPublication . Pires, Renata; Silva, Tiago; Ribeiro, Cláudia; Costa, Luis; Matos, Cristina T.; Costa, Paula; Lopes, Tiago; Gírio, Francisco; Silva, CarlaABSTRACT: Industrial liquid effluents (e.g., from fertilizer industry) and flue gas streams (e.g., CO2-rich, from cement industry) arise as an opportunity for waste valorization. Microalgae are suitable biomass for assimilating both effluents at the cultivation stage. Under a biorefinery concept, given the urge for energy transition in the aviation sector, this research explores the transformation of a microalgae consortium grown at an industrial site in Portugal and its subsequent harvesting, hydrothermal liquefaction (HTL), and bio-oil refining. A life cycle assessment (LCA) approach is undertaken with two functional units (FU): 1 kg of microalgae dry-cell weight (dw) and 1 MJ of bio-jet fuel. The latter follows an attributional approach with energy allocation for comparison with the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) guidelines. HTL is based on data from bench-scale experiments and literature, whereby the Petroleum Refinery Life Cycle Inventory Model (PRELIM) is used to mimic bio-oil refining. Following this approach, achieving Sustainable Aviation Fuel (SAF) compliance requires net-zero electricity (0 gCO2eq/kWh), with an HTL bio-oil yield of 55.6 % dw (the maximum observed), a minimum refining bio-jet fuel yield of at least 16 %. Alternatively, an HTL bio-oil yield of 36.9 % dw (the median observed) with a refining efficiency of at least 24.3 %.
- Chemical and biological-based isoprene production: Green metricsPublication . Morais, Ana Rita C.; Dworakowska, Sylwia; Reis, Alberto; Gouveia, Luisa; Matos, Cristina T.; Bogdal, Dariusz; Lukasik, Rafal M.Green metrics is a methodology which allows the greenness of either new or already existing processesto be assessed. This paper is a part of a special issue devoted to green metrics in which this methodologyis applied to different processes to assess bio and petrochemical routes. In this work, green metrics wereused as a tool to validate and compare the petrochemical and biological processes of isoprene production.The Sumitomo process has been selected for this comparison as it is beneficial because of it using lessexpensive C1components as well as the fact that it has lower investment costs for a single-step process. The production of isoprene through a modified Escherichia coli bacterial process has been selected forcomparison with the fossil pathway. The green metrics evaluation was performed for both processes toproduce isoprene and to target 50,000 tonnes of isoprene yearly. Although, the calculated costs for the bio-isoprene are slightly higher than the actual market price ofits fossil counterpart, the results obtained reveal that the bacteria-based isoprene production is able to substitute the petrochemical process, with material and energy efficiency. This conclusion has also beenproved by the increasing number of industrial interest in bioisoprene. The challenge comes from the landuse needed for the production of a carbon source which might be solved by the use of waste and residueswhich are rich in carbohydrates or lignocellulosic biomass which can be converted to simple sugars.
- Conceptual Design of an Autotrophic Multi-Strain Microalgae-Based Biorefinery: Preliminary Techno-Economic and Life Cycle AssessmentsPublication . Lopes, Tiago; Ortigueira, Joana; Matos, Cristina T.; Costa, Luis; Ribeiro, Cláudia; Reis, Alberto; Gírio, FranciscoABSTRACT: Microalgae represent a promising solution in addressing the impacts associated with the current agricultural and manufacturing practices which are causing irreparable environmental damage. Microalgae have considerable biosynthetic potential, being a rich source of lipids, proteins, and high-value compounds. Under the scope of the H2020-BBI MULTI-STR3AM project, an innovative large-scale production system of valuable commodities for the food, feed, and fragrance sectors is being developed on the basis of microalgae, reducing costs, increasing the scale of production, and boosting value chain sustainability. In this work, we aimed to create a process model that can mimic an industrial plant to estimate mass and energy balances, optimize scheduling, and calculate production costs for a large-scale plant. Three autotrophic microalgae strains (Nannochloropsis sp., Dunaliella sp. and Spirulina sp.) were considered for this assessment, as well as the use of locally sourced CO2 (flue gas). The developed process model is a useful tool for obtaining the data required for techno-economic analysis (TEA) and life cycle assessment (LCA) of industrial biorefinery-based processes. Nannochloropsis sp. was the most economic option, whereas Dunaliella sp. was the most expensive strain to produce due to its lower productivity. Preliminary environmental assessments of the climate change impact category revealed that water recirculation and the use of flue gas could lead to values of 5.6, 10.6, and 9.2 kgCO(2eq)center dot kg(AFDW)(-1) for Nannochloropsis sp., Dunaliella sp., and Spirulina sp., respectively, with electricity and NaCl as the main contributors. The obtained data allow for the quantification of the production costs and environmental impacts of the microalgal biomass fractions produced, which will be fundamental for future comparison studies and in determining if they are higher or lower than those of the replaced products. The process model developed in this work provides a useful tool for the evaluation and optimization of large-scale microalgae production systems.
- Effect of light on the production of bioelectricity and added-value microalgae biomass in a photosynthetic alga microbial fuel cellPublication . Gouveia, Luisa; Neves, Carole; Sebastião, Diogo; Nobre, B. P.; Matos, Cristina T.This study demonstrates the simultaneous production of bioelectricity and added-value pigments in a Photosynthetic Alga Microbial Fuel Cell (PAMFC). A PAMFC was operated using Chlorella vulgaris in the cathode compartment and a bacterial consortium in the anode. The system was studied at two different light intensities and the maximum power produced was 62.7 mW/m2 with a light intensity of 96 lE/(m2 s). The results showed that increasing light intensity from 26 to 96 lE/(m2 s) leads to an increase of about 6-folds in the power produced. Additionally, the pigments produced by the microalga were analysed and the results showed that the light intensity and PAMFC operation potentiated the carotenogenesis in the cathode compartment. The demonstrated possibility of producing added-value microalgae biomass in microbial fuel cell cathodes will increase the economic feasibility of these bioelectrochemical systems, allowing the development of energy efficient systems for wastewater treatment and carbon fixation.
- Green metrics evaluation of isoprene production by microalgae and bacteriaPublication . Matos, Cristina T.; Gouveia, Luisa; Morais, Ana Rita C.; Reis, Alberto; Lukasik, Rafal M.Isoprene is a key intermediate compound for the production of synthetic rubber and adhesives and is also used as a building block in the chemical industry. Traditionally, isoprene is obtained from crude oil during the refinery process. Nevertheless, plants and animals are also able to synthesize this important compound. This work compares two renewable approaches for isoprene production: by photosynthetic organisms (autotrophic microalgae/cyanobacteria) and by heterotrophic organisms (bacteria). These are two alternative pathways for the conventional isoprene production obtained from the petrochemicalbased refinery process, which were assessed in this work using green metrics. Their performance was evaluated in terms of: material efficiency, energy efficiency, economic evaluation and land use. A 10-tonne scale was chosen to perform the green metrics evaluation for both biological processes leading to isoprene. For each process, a comparison was made between a scenario considering the highest isoprene produced reported in the literature and a scenario considering the maximum theoretical stoichiometric isoprene productivity.
- Implementation of sustainability criteria for biofuels and bioliquids in PortugalPublication . Matos, Cristina T.; Gírio, Francisco; Oliveira, Ana Cristina; Silva, Luís; Lukasik, Rafal M.
- Life cycle assessment of advanced bioethanol production from pulp and paper sludgePublication . Sebastião, Diogo; Gonçalves, Margarida S.; Marques, Susana; Fonseca, César; Gírio, Francisco; Oliveira, Ana Cristina; Matos, Cristina T.This work evaluates the environmental performance of using pulp and paper sludge as feedstock for the production of second generation ethanol. An ethanol plant for converting 5400 tons of dry sludge/year was modelled and evaluated using a cradle-to-gate life cycle assessment approach. The sludge is a burden for pulp and paper mills that is mainly disposed in landfilling. The studied system allows for the valorisation of the waste, which due to its high polysaccharide content is a valuable feedstock for bioethanol production. Eleven impact categories were analysed and the results showed that enzymatic hydrolysis and neutralisation of the CaCO3 are the environmental hotspots of the system contributing up to 85% to the overall impacts. Two optimisation scenarios were evaluated: (1) using a reduced HCl amount in the neutralisation stage and (2) co-fermentation of xylose and glucose, for maximal ethanol yield. Both scenarios displayed significant environmental impact improvements.
- Life-cycle assessment of microalgae biodiesel: a reviewPublication . Figueiredo, Filipa; Garcia, Rita; Gonçalves, Margarida S.; Castanheira, Érica; Malça, João; Oliveira, Ana Cristina; Matos, Cristina T.; Freire, FaustoMicroalgae are an attractive way to produce biofuels due to the ability to accumulate lipids and very high photosynthetic yields. This article presents a review of life-cycle assessment studies of microalgae biodiesel production, including an analysis of modeling choices and assumptions. A high variation in GHG emissions (between -0.75 and 2.9 kg CO2eq MJ-1) was found and the main causes were investigated, namely modeling choices (e.g. the approach used to deal with multifunctionality), and a high parameter uncertainty in microalgae cultivation, harvesting and oil extraction processes.
- Membrane separation and characterisation of lignin and its derived products obtained by a mild ethanol organosolv treatment of rice strawPublication . Moniz, Patricia; Serralheiro, Cláudia; Matos, Cristina T.; Boeriu, Carmen G.; Frissen, Augustinus E.; Duarte, Luís C.; Roseiro, Luisa B.; Pereira, Helena; Carvalheiro, FlorbelaABSTRACT: An organosolv process using ethanol-water was optimized in order to recover high quality lignin from rice-straw previously pre-treated by autohydrolysis at 210 °C. The results showed a selective and appreciable removal of lignin under very mild conditions and the highest delignification yield occurred at 30 °C. The lignin extracts were characterised using capillary zone electrophoresis (CZE), size exclusion chromatography (SEC), Fourier transform infrared spectroscopy (FT-IR) and 31P-NMR, and two-dimensional heteronuclear single quantum correlation NMR spectroscopy (2D-HSQC NMR), which enabled the identification of low molecular weight lignins with a syringyl/guaiacyl ratio of about 0.74 containing phenolic compounds with potential bioactive properties. In order to separate the target compounds, membrane technology has been used and an enriched extract containing value-added phenolic compounds such as tricin, vanillin, ferulic acid and p-coumaric acid was obtained. High membrane efficiency (around 80%) was obtained for target compounds.