ISEL - Eng. Quim. Biol. - Artigos
Permanent URI for this collection
Browse
Recent Submissions
- P-xylene oxidation to terephthalic acid: New trendsPublication . dos Anjos Carvalho Lapa, Hugo Miguel; Martins, LuisaLarge-scale terephthalic acid production from the oxidation of p-xylene is an especially important process in the polyester industry, as it is mainly used in polyethylene terephthalate (PET) manufacturing, a polymer that is widely used in fibers, films, and plastic products. This review presents and discusses catalytic advances and new trends in terephthalic acid production (since 2014), innovations in terephthalic acid purification processes, and simulations of reactors and reaction mechanisms.
- Blood molecular profile to predict genotoxicity from exposure to antineoplastic drugsPublication . Ladeira, Carina; Araújo, Rúben; Ramalhete, Luís; Teixeira, Hélder; Calado, CecíliaGenotoxicity is an important information that should be included in human biomonitoring programmes. How-ever, the usually applied cytogenetic assays are laborious and time-consuming, reason why it is critical to develop rapid and economic new methods. The aim of this study was to evaluate if the molecular profile of frozen whole blood, acquired by Fourier Transform Infrared (FTIR) spectroscopy, allows to assess genotoxicity in occupational exposure to antineoplastic drugs, as obtained by the cytokinesis-block micronucleus assay. For that purpose, 92 samples of peripheral blood were studied: 46 samples from hospital professionals occupationally exposed to antineoplastic drugs and 46 samples from workers in academia without exposure (controls). It was first evaluated the metabolome from frozen whole blood by methanol precipitation of macromolecules as haemoglobin, followed by centrifugation. The metabolome molecular profile resulted in 3 ratios of spectral bands, significantly different between the exposed and non-exposed group (p < 0.01) and a spectral principal component-linear discriminant analysis (PCA-LDA) model enabling to predict genotoxicity from exposure with 73 % accuracy. After optimization of the dilution degree and solution used, it was possible to obtain a higher number of significant ratios of spectral bands, i.e., 10 ratios significantly different (p < 0.001), highlighting the high sensitivity and specificity of the method. Indeed, the PCA-LDA model, based on the molecular profile of whole blood, enabled to predict genotoxicity from the exposure with an accuracy, sensitivity, and specificity of 92 %, 93 % and 91 %, respectively. All these parameters were achieved based on 1 mu L of frozen whole blood, in a high-throughput mode, i.e., based on the simultaneous analysis of 92 samples, in a simple and economic mode. In summary, it can be conclude that this method presents a very promising potential for high-dimension screening of exposure to genotoxic substances.
- The hypocholesterolemic potential of the edible algae fucus vesiculosus: Proteomic and quantitative PCR analysisPublication . André, Rebeca; Pacheco, Rita; Alves, Ana Catarina; Santos, Hugo M. M.; Bourbon, Mafalda; Serralheiro, Maria LuisaA brown seaweed consumed worldwide, Fucus vesiculosus, has been used to prevent atherosclerosis and hypercholesterolemia, among other uses. However, the mechanisms of action that lead to these effects are not yet fully understood. This work aims to study the in vitro effect of an aqueous extract of F. vesiculosus, previously characterized as rich in phlorotannins and peptides, on the expression of different proteins involved in the synthesis and transport of cholesterol. A proteomic analysis, Western blot, and qRT-PCR analysis were performed to identify protein changes in HepG2 cells exposed to 0.25 mg/mL of the F. vesiculosus extract for 24 h. The proteomic results demonstrated that, in liver cells, the extract decreases the expression of four proteins involved in the cholesterol biosynthesis process (CYP51A1, DHCR24, HMGCS1 and HSD17B7). Additionally, a 12.76% and 18.40% decrease in the expression of two important transporters proteins of cholesterol, NPC1L1 and ABCG5, respectively, was also observed, as well as a 30% decrease in NPC1L1 mRNA levels in the cells exposed to the extract compared to control cells. Our study reveals some of the mechanisms underlying the actions of bioactive compounds from F. vesiculosus that may explain its previously reported hypocholesterolemic effect, future prospecting its use as a functional food.
- 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.