Percorrer por autor "Carvalho, Maria de Fátima"
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- Bioreciclagem têxtil e saúde ambiental: uma abordagem inovadora para a redução de riscos e promoção da sustentabilidadePublication . Almeida, Liliana; Alexandrino, Diogo A. M.; Ribeiro, Nuno; Oliveira, Rui S.; Carvalho, Maria de Fátima; Freitas, Marisa; Alexandrino, DiogoA poluição associada à indústria têxtil representa um desafio crescente para a saúde pública e ambiental. O descarte inadequado de resíduos têxteis, frequentemente em aterros, ou o seu tratamento por incineração (Azcona et al., 2023), contribui para a emissão de compostos tóxicos, microplásticos e partículas inaláveis, com efeitos adversos sobre a qualidade do ar, da água e do solo (Shirvanimoghaddam et al., 2020; Juanga-Labayen et al., 2022). Assim, é urgente promover estratégias de gestão sustentável deste tipo de resíduos que minimizem riscos para a saúde humana e para os ecossistemas. O presente trabalho visa desenvolver e avaliar processos de bioreciclagem de resíduos têxteis com base em microrganismos celulolíticos, como alternativa ecológica às práticas convencionais. O estudo tem sido conduzido com base numa abordagem interdisciplinar que integra metodologias da microbiologia ambiental, biotecnologia e saúde ambiental. Inicialmente, procedeu-se à caracterização físico-química dos resíduos têxteis pós-industriais e pós-consumo. Posteriormente, realizaram-se ensaios de biodegradação in vitro. Estes ensaios possibilitaram monitorizar parâmetros ambientais e observar alterações estruturais nas fibras têxteis, avaliando a sua suscetibilidade à degradação biológica. Paralelamente, foram isolados microrganismos a partir de diferentes matrizes ambientais, incluindo composto, solo e efluentes, recorrendo a meios seletivos para microrganismos celulolíticos. A caracterização dos resíduos têxteis permitiu definir as configurações experimentais a testar, centradas em fibras de algodão e liocel, tingidas e não tingidas. Os ensaios de biodegradação realizados evidenciaram alterações morfológicas e estruturais nas fibras, compatíveis com processos iniciais de despolimerização e fragmentação da celulose. Paralelamente, o isolamento de microrganismos resultou na obtenção de diversas colónias com atividade celulolítica. Entre os isolados identificados destacam-se fungos dos géneros Neurospora e Aspergillus, bem como bactérias dos géneros Glutamicibacter e Bacillus, reconhecidos pelo seu potencial na degradação de polímeros de origem celulósica. Os resultados preliminares deste estudo sugerem que a (bio)reciclagem pode constituir uma alternativa eficaz e ambientalmente segura às práticas convencionais de gestão de resíduos têxteis, contribuindo para a redução da poluição e da consequente exposição humana a compostos tóxicos. A integração de microrganismos celulolíticos em processos de gestão de resíduos poderá representar um avanço relevante na promoção da saúde ambiental e na prevenção de riscos sanitários associados à indústria têxtil.
- Biotechnological potential of Macroalgae associated ActinomycetotaPublication . Moreira, Gabriela Alves; Girão, Mariana; Eusébio, Nádia; Mendes, Marta V.; Carvalho, Maria de Fátima; Alves Moreira, GabrielaActinomycetota are Gram-positive bacteria widely distributed across diverse environments, from ter-restrial to marine ecosystems, where they may occur as free-living organisms or in association with other organisms. This phylum is well-known for its remark-able biotechnological potential, with several members producing bioactive compounds such as antimicrobial and anticancer agents. However, macroalgae-associ-ated Actinomycetota remain underexplored despite having a metabolic potential comparable to free-living organisms.The main objective of this study was to explore the biosynthetic potential of 15 Actinomycetota isolates obtained from two marine macroalgae from the Por-tuguese coast, Codium tomentosum and Chondrus cris-pus, through the analysis of their genomes.Total DNA was sequenced using Illumina technology and 17 de novo genomes were assembled. Phyloge-nomic analysis identified 5 different genera, Actinoal-loteichus, Cellulosimicrobium, Kocuria, Nocardia and Streptomyces, with 3 putative novel species.Genome mining, using manually curated antiSMASH data, identified 452 biosynthetic gene clusters (BGCs) across 21 metabolite classes. Among the BGCs iden-tified are antimicrobial and anticancer compounds, siderophores and conserved metabolites. More than 60% of these BGCs have none or low similarity to pre-viously known compounds, which can be an indicator of novelty. Compared with Streptomyces, one of the most studied genera, non-Streptomyces genera exhib-ited a higher novelty percentage (ca. 80%).Additionally, BiG-SCAPE and clinker were used to visualize the data and assess the similarity between BGCs for the same compound in different strains.Overall, these results confirm that macroalgae-as-sociated Actinomycetota represent a valuable and underexplored source of new species and biosynthet-ic diversity, supporting further study of this bacterial group.
- Exploring the biosurfactant potential of Actinobacteria isolated from Ruta graveolensPublication . Ferreira, Sílvia; Ribeiro, Inês; Oliveira, Rui S.; Carvalho, Maria de FátimaBiosurfactants are surface-active compounds known for their emulsifying properties and numerous advantages, including low environmental toxicity, eco-friendliness, biodegradability and acceptability. These molecules are amphiphilic, containing both hydrophilic and hydrophobic ends, allowing them to interact at the aqueous-non-aqueous interface. Bacterial biosurfactants are interesting due to their various fields of applications, including biomedicine, cosmetics, food, pharmaceutics, water treatment and oil recovery. Actinobacteria are an important group of microorganisms with high potential for producing different bioactive metabolites including antimicrobial, anticancer and other pharmaceutical compounds. Medicinal plants,such as Ruta graveolens, are a rich source of bioactive compounds, and the association of actinobacteria endophytes with such plants are an attractive source for bioprospecting for novel compounds with biomedical and industrial applications. The purpose of this study was to explore the biosurfactant activity of actinobacterial strains previously isolated from R. graveolens. Fifteen previously isolated actinobacterial strains were inoculated into 100 mL Erlenmeyer flasks containing 30 mL of Kim’s broth supplemented with 3% filtered olive oil as a hydrophobic carbon source. After two weeks, biosurfactant productionwas analyzed by measuring the emulsification activity. Eight out of the 15 actinobacterial strains showed emulsification activity. All results were compared with a positive control consisting of Triton X100 (1mg/ml), and a negative control consisting in Kim’s broth. Almost all strains that revealed positive activity are affiliated to the actinobacterial species Tsukamurella tyrosinosolvens (7/8), with one strain belonging to the species Microbacterium gisengiterae. Comparative analysis with the positive control (with an emulsification activity of 60%), indicated that 3/8 samples showed high emulsification activity (>40%), 1 showed moderate activity (37%) and 4/8 showed low/moderate activity (20-30%). The subsequent phases of this study will involve analyzing if the potential biosurfactant compounds can reduce the surface tension and if they can represent new molecules.
- Exploring the fluoride resistome of two defluorinating bacteriaPublication . Alexandrino, Diogo A. M.; Carvalho, Maria de Fátima; Alexandrino, DiogoWith the increasing interest in bacterial defluorination as a bioremediation strategy to combat organofluorine pollution (including PFAS), fluoride toxicity arises as a bottleneck. Fluoride, an inevitable end product of these biocatalytic processes, is highly bacteriostatic even at micro- and millimolar levels, limiting the efficiency of enzymatic defluorination. Intracellular fluoride leads to rapid metabolic arrest by inhibiting essential enzymes in central metabolism and may also cause cytoplasmic acidification in low pH environments. While bacteria have evolved specialized membrane shuttles regulated by fluoride-specific riboswitches to export intracellular fluoride from the cell, their deployment during bacterial defluorination has shown to be insufficient in preventing fluoride-induced loss of metabolic viability. And yet, some defluorinating bacteria can accommodate the stoichiometric defluorination of fluorinated compounds that lead to the release of fluoride significantly beyond the known toxic thresholds of this halide for bacteria. In this light, this work aimed to study the transcriptome of two model defluorinating bacteria under fluoride stress, to characterize their homeostatic response and potentially highlight new functional traits linked to their tolerance to intracellular fluoride. Delftia acidovorans MFA5 and Labrys portucalensis F11 were used as model strains for this study, given their capacity to defluorinate aliphatic and aromatic organofluorines. We conducted Minimum Inhibitory Concentration (MIC) assays with these strains to establish their susceptibility threshold towards fluoride. Then, we conducted an expression study by exposing these strains to fluoride at sub-MIC levels for 72 hours, taking samples for RNA-seq every 24 hours. Once we acquire the RNA-seq transcriptomic datasets, we plan to map them to each strain’s genome and perform quantitative expression analyses to reveal differentially-regulated transcripts under fluoride exposure. Results obtained so far showed high fluoride MICs for both MFA5 (500 mM) and F11 (250 mM), confirming their unusual tolerance to this halide. Resolving their transcriptomes under fluoride exposure at sub-MIC levels will allow us to establish a functional map of the homeostatic response of F11 and MFA5 towards fluoride, focused on looking for potentially novel traits of resistance that may explain their unusual tolerance to the halide.
- In vitro antimicrobial activity of volatile compounds from the Lichen Pseudevernia furfuracea (L.) Zopf. against multidrug-resistant bacteria and fish pathogensPublication . Essadki, Yasser; Hilmi, Adel; Cascajosa-Lira, Antonio; Girão, Mariana; Darrag, El Mehdi; Rosário Martins, Maria; Romane, Abderrahmane; Zerrifi, Soukaina El Amrani; Mugani, Richard; Tazart, Zakaria; Redouane, El Mahdi; Jos, Angeles; Cameán, Ana M.; Vasconcelos, Vitor; Campos, Alexandre; Khalloufi, Fatima El; Oudra, Brahim; Barakate, Mustapha; Carvalho, Maria de FátimaLichens are symbiotic organisms with unique secondary metabolism. Various metabolites from lichens have shown antimicrobial activity. Nevertheless, very few studies have investigated the antimicrobial potential of the volatile compounds they produce. This study investigates the chemical composition and antimicrobial properties of volatile compounds from Pseudevernia furfuracea collected in two regions of Morocco. Hydrodistillation was used to obtain volatile compounds from samples collected in the High Atlas and Middle Atlas. Gas chromatography–mass spectrometry (GC-MS) analysis identified phenolic cyclic compounds as the primary constituents, with atraric acid and chloroatranol being the most abundant. Additionally, eight compounds were detected in lichens for the first time. The antimicrobial activity of these compounds was assessed using disc diffusion and broth microdilution methods. Both samples demonstrated significant antimicrobial effects against multidrug-resistant human bacteria, reference microorganisms, fish pathogens, and Candida albicans, with minimum inhibitory concentrations (MICs) ranging from 1000 µg/mL to 31.25 µg/mL. This study provides the first report on the volatile compounds from Pseudevernia furfuracea and their antimicrobial effects, particularly against fish pathogens, suggesting their potential as novel antimicrobial agents for human and veterinary use. Further research is warranted to explore these findings in more detail.
- MarinEye – A tool for marine monitoringPublication . Martins, Alfredo; Dias, André; Silva, Eduardo; Ferreira, Hugo; Dias, Ireneu; Almeida, José Miguel; Torgo, Luís; Gonçalves, Marco; Guedes, Maurício; Dias, Nuno; Jorge, Pedro; Mucha, Ana Paula; Magalhães, Catarina; Carvalho, Maria de Fátima; Ribeiro, Hugo; Almeida, C. Marisa R.; Azevedo, Isabel; Ramos, Sandra; Borges, Teresa; Leandro, Sérgio Miguel; Maranhão, Paulo; Mouga, Teresa; Gamboa, Roberto; Lemos, Marco; Santos, Antonina dos; Silva, Alexandra; Teixeira, Bárbara Frazão e; Bartilotti, Cátia; Marques, Raquel; Cotrim, SóniaThis work presents an autonomous system for marine integrated physical-chemical and biological monitoring – the MarinEye system. It comprises a set of sensors providing diverse and relevant information for oceanic environment characterization and marine biology studies. It is constituted by a physical-chemical water properties sensor suite, a water filtration and sampling system for DNA collection, a plankton imaging system and biomass assessment acoustic system. The MarinEye system has onboard computational and logging capabilities allowing it either for autonomous operation or for integration in other marine observing systems (such as Observatories or robotic vehicles. It was designed in order to collect integrated multi-trophic monitoring data. The validation in operational environment on 3 marine observatories: RAIA, BerlengasWatch and Cascais on the coast of Portugal is also discussed.
- Uncovering microbial drivers of cellulosic textile degradation in composting environmentsPublication . Almeida, Liliana; Alexandrino, Diogo A. M.; Oliveira, Rui S.; Carvalho, Maria de Fátima; Freitas, Marisa; Alexandrino, DiogoThe exponential growth of global textile production, coupled with inadequate waste management infrastructure, has intensified the environmental burden of textile waste. Of particular concern is the cellulose-rich fraction, comprising natural and regenerated fibres, which remains largely excluded from effective recycling pathways. Its high abundance and untapped potential for microbial degradation underscore the need for targeted strategies. Leveraging the metabolic capabilities of specialised microbial communities within composting environments offers a promising route to address this gap, enabling sustainable bioconversion of cellulosic textiles into value-added products. This study investigates the potential of composting as a biologically driven strategy for the sustainable treatment of cellulosic textile waste. Methods: Cotton and lyocell fabrics, in both whole and shredded forms, were subjected to industrial (55 days) and community (90 days) composting processes conducted at a urban waste treatment and recovery Association (LIPOR, Portugal). Upon completion of the composting process, compost and textile samples were collected for downstream analyses, including culture-based and metagenomic approaches. Results: Degradation efficiency, determined through dry mass weight loss, was significantly higher in shredded samples (p 93% mass loss for both fabrics. Shotgun metagenomic analysis revealed microbial communities predominantly composed of Actinomycetota, Bacillota and Ascomycota. Functional annotation highlighted a rich repertoire of carbohydrate-active enzymes (CAZymes), notably glycoside hydrolases (GH), with the highest abundance detected in lyocell samples from community composting. Notably, cellulosome-associated domains were exclusively identified in lyocell samples. Complementary culture-based screening yielded 48 cellulolytic isolates across genera such as Bacillus, Aspergillus, and Neurospora. Conclusions: These findings position composting as a promising strategy for valorising cellulosic textile waste and as a potential foundation for advancing biotechnological innovations in textile waste management.
- Unveiling Lichen’s Hidden Arsenal against multidrug resistance: A Systematic Review of their essential oils, volatile compounds and extracts with antimicrobial applicationsPublication . Essadki, Yasser; El Amrani Zerrifi, Soukaina; Carvalho, Maria de Fátima; Barros, Lillian; Vasconcelos, Vitor; Campos, Alexandre; El Khalloufi, Fatima; Oudra, Brahim; Martins, Rosário; Martins, RosarioThe increase in multidrug resistance in microorganisms and the rise of emergent infectious diseases worldwide is a threat to human and animal health. Therefore, research on new molecules with antibiotic potential is a priority. Lichens have a unique secondary metabolism with relatively untapped potential, yet their essential oils (EOs) and volatile organic compounds (VOCs) remain a relatively untapped resource. This systematic review was conducted following PRISMA 2020 guidelines, with a comprehensive search performed in the Web of Science database for studies published up to 2023. From 254 identified records, six studies involving nine lichen species (Evernia prunastri, Evernia divaricata, Cladonia rangiformis, Cladonia furcata, Parmotrema perlatum, Lichina pygmaea, Parmelia perlata, Hypogymnia physodes, and Parmelia sulcata) met the eligibility criteria. The synthesized data show that these volatile fractions possess significant antimicrobial potential, with minimum inhibitory concentrations (MICs) generally lower than 1 mg/mL. Major bioactive constituents identified include atraric acid, orsellinates, and various sesquiterpenes. While the current evidence highlights a strong potential of lichen volatiles against pathogens, research is limited to a small fraction of known species. This review identifies a critical gap in testing these compounds directly against MDR clinical isolates and suggests that future research should focus on high-biomass species and the heterologous expression of lichen biosynthetic genes to develop sustainable antimicrobial applications.