ISEL - Eng. Quim. Biol. - Artigos
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- Edible seaweeds extracts: characterization and functional properties for health conditionsPublication . Coelho, Mariana; Duarte, Ana Patrícia; Pinto, Sofia; Botelho, Hugo M.; Reis, Catarina Pinto; Serralheiro, Maria Luísa; Pacheco, RitaSeaweeds are popular foods due to claimed beneficial health effects, but for many there is a lack of scientific evidence. In this study, extracts of the edible seaweeds Arame, Nori, and Fucus are compared. Our approach intends to clarify similarities and differences in the health properties of these seaweeds, thus contributing to target potential applications for each. Additionally, although Arame and Fucus seaweeds are highly explored, information on Nori composition and bioactivities is scarce. The aqueous extracts of the seaweeds were obtained by decoction, then fractionated and characterized according to their composition and biological activity. It was recognized that fractioning the extracts led to bioactivity reduction, suggesting a loss of bioactive compounds synergies. The Arame extract showed the highest antioxidant activity and Nori exhibited the highest potential for acetylcholinesterase inhibition. The identification of the bioactive compounds in the extracts allowed to see that these contained a mixture of phloroglucinol polymers, and it was suggested that Nori's effect on acetylcholinesterase inhibition may be associated with a smaller sized phlorotannins capable of entering the enzyme active site. Overall, these results suggest a promising potential for the use of these seaweed extracts, mainly Arame and Nori, in health improvement and management of diseases, namely those associated to oxidative stress and neurodegeneration.
- Exploring the hypocholesterolemic potential of a fucus vesiculosus extract: Omic insights into molecular mechanisms at the intestinal levelPublication . André, Rebeca; Pacheco, Rita; Santos, Hugo M.; Serralheiro, Maria LuísaHigh blood cholesterol levels are a major risk factor for cardiovascular diseases. A purified aqueous extract of Fucus vesiculosus, rich in phlorotannins and peptides, has been described for its potential to inhibit cholesterol biosynthesis and intestinal absorption. In this work, the effect of this extract on intestinal cells' metabolites and proteins was analysed to gain a deeper understanding of its mode of action on lipids' metabolism, particularly concerning the absorption and transport of exogenous cholesterol. Caco-2 cells, differentiated into enterocytes, were exposed to the extract, and analysed by untargeted metabolomics and proteomics. The results of the metabolomic analysis showed statistically significant differences in glutathione content of cells exposed to the extract compared to control cells, along with an increased expression of fatty acid amides in exposed cells. A proteomic analysis showed an increased expression in cells exposed to the extract compared to control cells of FAB1 and NPC1, proteins known to be involved in lipid metabolism and transport. To the extent of our knowledge, this study is the first use of untargeted metabolomics and a proteomic analysis to investigate the effects of F. vesiculosus on differentiated Caco-2 cells, offering insights into the molecular mechanism of the extract's compounds on intestinal cells.
- A wide array of lignin-related phenolics are oxidized by an evolved bacterial dye-decolourising peroxidasePublication . Silva, Diogo; Sousa, Ana Catarina; Robalo, Maria Paula; Martins, Lígia O.Lignin is the second most abundant natural polymer next to cellulose and by far the largest renewable source of aromatic compounds on the planet. Dye-decolourising peroxidases (DyPs) are biocatalysts with immense potential in lignocellulose biorefineries to valorize emerging lignin building blocks for environmentally friendly chemicals and materials. This work investigates the catalytic potential of the engineered PpDyP variant 6E10 for the oxidation of 24 syringyl, guaiacyl and hydroxybenzene lignin-phenolic derivatives. Variant 6E10 exhibited up to 100-fold higher oxidation rates at pH 8 for all the tested phenolic substrates compared to the wild-type enzyme and other acidic DyPs described in the literature. The main products of reactions were dimeric isomers with molecular weights of (2 × MWsubstrate - 2 H). Their structure depends on the substitution pattern of the aromatic ring of substrates, i.e., of the coupling possibilities of the primarily formed radicals upon enzymatic oxidation. Among the dimers identified were syringaresinol, divanillin and diapocynin, important sources of structural scaffolds exploitable in medicinal chemistry, food additives and polymers.
- Home trash biomass valorization by catalytic pyrolysisPublication . Rijo, Bruna; Dias, Ana Paula Soares; Jesus, Nicole de; Pereira, Manuel FranciscoWith the increase in population, large amounts of food waste are produced worldwide every day. These leftovers can be used as a source of lignocellulosic waste, oils, and polysaccharides for renewable fuels. In a fixed bed reactor, low-temperature catalytic pyrolysis was investigated using biomass gathered from domestic garbage. Thermogravimetry, under N2 flow, was used to assess the pyrolysis behavior of tea and coffee grounds, white potato, sweet potato, banana peels, walnut, almonds, and hazelnut shells. A mixture of biomass was also evaluated by thermogravimetry. Waste inorganic materials (marble, limestone, dolomite, bauxite, and spent Fluid Catalytic Cracking (FCC) catalyst) were used as catalysts (16.7% wt.) in the pyrolysis studies at 400 degrees C in a fixed bed reactor. Yields of bio-oil in the 22-36% wt. range were attained. All of the catalysts promoted gasification and a decrease in the bio-oil carboxylic acids content. The marble dust catalyst increased the bio-oil volatility. The results show that it is possible to valorize lignocellulosic household waste by pyrolysis using inorganic waste materials as catalysts.
- Biochemical methane potential assays for organic wastes as an anaerobic digestion feedstockPublication . Cabrita, Tiago Miguel; Santos, Maria TeresaThe anaerobic digestion process is applied worldwide in the treatment of various organic wastes, allowing energy production from biogas and organic recovery from digested sludge. In the evaluation of suitable substrates for anaerobic digestion, Biochemical Methane Potential assays are the most applied, and, despite several efforts to standardize this method, it is observed that there are still several studies that do not apply all the criteria. This current paper’s main goal is to present a review of anaerobic feedstocks, BMP methodologies, experimental conditions, and results of specific methane production from 2008 to 2023. A wide range of anaerobic feedstocks was found, which was divided into five groups: animal manure, sludge, food wastes, energy crops, and other organic wastes. Several parameters were used to characterize the anaerobic feedstocks, like TS, VS, COD, and pH, displaying different value ranges. The number of publications concerning BMP assays increased significantly over the years until 2021, having stabilized in the last two years. This evolution allowed for several attempts to standardize the BMP method with positive developments, but there are still some gaps in the experimental conditions and the determination of specific methane production. All of this makes the comparison of some studies a challenge.
- Low cost modified biochars from peanut shells for the removal of textile dyesPublication . Nunes, Nelson; Santos, Maria Teresa; Martins, AngelaBiochars from peanut shell wastes were produced and further modified with KOH and HNO3 to efficiently remove two industrial dyes, Mordant Orange 1 and Green Malachite oxalate, in aqueous systems. The materials were characterized through elemental analysis, N2 adsorption isotherms, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and the determination of the point of zero charge, pHPZC. The basic and, particularly, the acid treatments increased the specific surface area by 15 and 43%, respectively, and the pHPZC shifted from 6.2 to 9.1 or 3.3 upon treatments with KOH or HNO3. These modifications impacted the adsorption behavior of the dyes; in the case of Mordant Orange 1, the adsorption capacity increased 2 and 4 times, respectively, when compared with the parent biochar. These results show that the performance of biochars can improve substantially through simple modifications using acid or basic treatments that not only increase the specific surface area but also modify adsorbent/adsorbate interactions.
- Anti-hypercholesterolemia effects of edible seaweed extracts and metabolomic changes in Hep-G2 and Caco-2 cell linesPublication . Coelho, Mariana; Pacheco, RitaHypercholesterolemia is a major risk for the development of cardiovascular diseases (CVDs), the main cause of mortality worldwide, and it is characterized by high levels of circulating cholesterol. The drugs currently available for hypercholesterolemia control have several side effects, so it is necessary to develop new effective and safer therapies. Seaweeds serve as sources of several bioactive compounds with claimed beneficial effects. Eisenia bicyclis (Aramé) and Porphyra tenera (Nori) are edible seaweeds that were previously recognized as rich in bioactive compounds. In the present study, we aim to evaluate the anti-hypercholesterolemia effect of these two seaweed extracts and their health potential. Both extracts, but more efficiently Aramé extract, have liver 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) inhibitory activity as well as the capability to reduce approximately 30% of cholesterol permeation through human Caco-2 cells by simulating the intestinal lining, which is a target for hypercholesterolemia treatments. An untargeted metabolomic assay on human intestinal Caco-2 and liver Hep-G2 cell lines exposed to Aramé and Nori extracts revealed changes in the cells’ metabolism, indicating the extracts’ health beneficial effects. The metabolic pathways affected by exposure to both extracts were associated with lipid metabolism, such as phospholipids, and fatty acid metabolism, amino acid pathways, cofactors, vitamins, and cellular respiration metabolism. The effects were more profound in Aramé-treated cells, but they were also observed in Nori-exposed cells. The metabolite modifications were associated with the protection against CVDs and other diseases and to the improvement of the cells’ oxidative stress tolerance. The results obtained for the anti-hypercholesterolemia properties, in addition to the revelation of the positive impact on cell metabolism, offer an important contribution for further evaluation of these seaweed extracts as functional foods or for CVD prevention.
- Decision-making based on sustainability analysis using GREENSCOPEPublication . Dias, Ricardo N.; Filipe, Rui; Matos, Henrique A.Current economic and environmental pressure encourages companies to invest and reform processes in a sustainable way. However, the decision on the best sustainable investment in a given industry may not be as straightforward as given by the independent economic and environmental indicators. Analyzing such indicators for investment in process alternatives is a complex multi-objective decision-making process. Many methods can help solve multi-objective problems, GREENSCOPE suggests using the Addictive Utility Method, which may have some shortcomings. In this work, the Analytic Hierarchy Process and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) are applied to the indicator scores obtained with the GREENSCOPE methodology. The Analytical Hierarchy Process is applied with Marginal Rate of Substitution, to obtain the priority matrices. MATLAB was used to apply the methods and through an algorithm, to determine the adequate number of indicators to be used. Three cases were studied, namely a biorefinery plant, and two academic case studies on the production of acetaldehyde from ethanol and propylene glycol from glycerol. The two academic cases were modeled in Aspen Plus, to obtain process data, and linked to GREENSCOPE using MATLAB. The methodology was applied to some proposed alternatives where the sustainability improvement of energy integration and material recycling was tested. The new methodology was able to identify the more sustainable case among the alternatives. This methodology based on TOPSIS proved to be the best choice, avoiding the weighting of indicators, and providing an expected analytical decision among alternatives.
- Unlocking nature's potential: Modelling acacia melanoxylon as a renewable resource for bio-oil production through thermochemical liquefactionPublication . Ozkan, Sila; Sousa, Henrique; Gonçalves, Diogo; Puna, Jaime; Carvalho, Ana; Bordado, João; Santos, Rui Galhano dos; Gomes, JoãoThis study is focused on the modelling of the production of bio-oil by thermochemical liquefaction. Species Acacia melanoxylon was used as the source of biomass, the standard chemical 2-Ethylhexanol (2-EHEX) was used as solvent, p-Toluenesulfonic acid (pTSA) was used as the catalyst, and acetone was used for the washing process. This procedure consisted of a moderate acid-catalysed liquefaction process and was applied at 3 different temperatures to determine the proper model: 100, 135, and 170 degrees C, and at 30-, 115-, and 200-min periods with 0.5%, 5.25%, and 10% (m/m) catalyst concentrations of overall mass. Optimized results showed a bio-oil yield of 83.29% and an HHV of 34.31 MJ/kg. A central composite face-centred (CCF) design was applied to the liquefaction reaction optimization. Reaction time, reaction temperature, as well as catalyst concentration, were chosen as independent variables. The resulting model exhibited very good results, with a highly adjusted R-squared (1.000). The liquefied products and biochar samples were characterized by Fourier-transformed infrared (FTIR) and thermogravimetric analysis (TGA); scanning electron microscopy (SEM) was also performed. The results show that invasive species such as acacia may have very good potential to generate biofuels and utilize lignocellulosic biomass in different ways. Additionally, using acacia as feedstock for bio-oil liquefaction will allow the valorisation of woody biomass and prevent forest fires as well. Besides, this process may provide a chance to control the invasive species in the forests, reduce the effect of forest fires, and produce bio-oil as a renewable energy.
- Sustainability analysis of a solar-driven calcium looping plant for thermochemical energy storagePublication . Dias, Ricardo N.; Filipe, Rui; Matos, Henrique A.Sustainable development is essential to ensure that future generations enjoy the same or better standard of living as today's society. Clean energy will play an important role in this. Concentrated solar power is one of the cleanest ways to harness solar power and convert it into useable energy like electricity. However, due to the intermittent nature of solar power production, concentrated solar power needs to be coupled with energy storage to ensure the ability to produce and release electricity during peak demand periods. Calcium looping for thermochemical energy storage is an emerging technology that uses calcium carbonate, a highly abundant and inexpensive material, to store energy in the form of calcium oxide and carbon dioxide. A sustainability analysis of a solar-driven calcium looping plant for thermochemical energy storage process is performed in this work. Several process alternatives, previously modelled in Aspen Plus (R), are assessed using three sustainability analysis tools, GREENSCOPE, SimaPro, and OpenLCA. Nine process alternatives are considered, including the use of sorbent purge, water vapor as fluidization fluid at the calciner, and different operating temperatures in the calciner. All the analysis tools identified the process alternative using total sorbent purge, water vapor as fluidization fluid and a calciner temperature of 800 degrees C as the best overall performer. This work contributes through a sustainability analysis to the decision-making on which process configuration and conditions should be used, building on a previous technical analysis of a calcium looping for thermochemical energy storage process.