Percorrer por autor "cordeiro, nereida"
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- Development and preliminary validation of an analytical methodology for the determination of organic UV filters in zooplankton samplesPublication . Íñiguez, Eva; Gouazé, Margaux; Dinis, Ana; Sosa-Ferrera, Zoraida; Cordeiro, Nereida; Kaufmann, Manfred; Montesdeoca-Esponda, Sarah; Iñiguez Santamaría, Eva; Dinis, Ana; cordeiro, nereida; Kaufmann, ManfredThe release of chemicals into marine environments from coastal human activities has raised growing concern about pollution. Among these chemicals, organic ultraviolet filters (oUVFs), widely used in personal care products and industrial applications, have recently been identified as pollutants of emerging concern. Their extensive use and persistence highlight the need to assess their occurrence and potential impacts on aquatic ecosystems. This study aimed to optimize and apply an analytical methodology for the determination of eleven oUVFs in zooplankton matrices. Microwave-assisted extraction (MAE) was employed for sample preparation, while ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) enabled the identification and quantification of the target compounds. Extraction parameters, including solvent, temperature, and time, were systematically optimized to enhance recovery and ensure accuracy and precision in complex biological samples. The method achieved limits of detection (MLOD) between 1.47 and 5.98 ng g weight (d.w.) and method limits of quantification (MLOQ) between 4.900 and 19.92 ng g 1 1 dry d.w. Recovery ef ficiencies were low, ranging from 28 to 63 %, reflecting the diverse physicochemical properties of oUVFs and the strong matrix effects associated with zooplankton heterogeneity. Application of the validated method to zooplankton collected around Madeira Island (Portugal) revealed the presence of six oUVFs. Homosalate was the most frequently detected compound (53 % of samples), while octocrylene exhibited the highest concentrations, ranging from 24.01 to 1029 ng g 1 d.w. These findings demonstrate the relevance of zooplankton as bio indicators of oUVF contamination and support the need for regulatory monitoring and ecological risk assess ments in coastal ecosystems.
- Microplastic ingestion and plastic additive detection in pelagic squid and fish: implications for bioindicators and plastic tracers in open oceanic food websPublication . Sambolino, Annalisa; Iniguez, Eva; Herrera, Inma; Kaufmann, Manfred ; Dinis, Ana; Cordeiro, Nereida ; Sambolino, Annalisa; Iñiguez Santamaría, Eva; Kaufmann, Manfred; cordeiro, nereidaThe ubiquitous presence of microplastics (MPs) in the ocean represents a potential threat to marine organisms, with poorly understood long-term adverse effects, including exposure to plastic additives. The present study investigated the ingestion of MPs in two epipelagic fish species (Trachurus picturatus and Scomber colias) and three pelagic squid spe cies (Loligo vulgaris, Ommastrephes caroli and Sthenoteuthis pteropus) from an open oceanic region of the Northeast Atlan tic. Seven phthalate esters (PAEs) were also analysed in the organisms' tissue, and the potential correlation between PAEs concentrations and ingested MPs was investigated. Seventy-two fish and 20 squid specimens were collected and analysed. MPs were found in the digestive tract of all species and in the squid species' gills and ink sacs. The highest occurrence of MPs was in the stomach of S. colias (85 %) and the lowest in the stomach and ink sac of O. caroli and L. vulgaris (12 %). Most of the particles identified (>90 %) were fibres. Among all the ecological and biological factors considered (dietary preferences, season, body size, total weight, liver weight, hepatosomatic index and gastrosomatic index), only gastrosomatic index (GSI) and season were significant predictors of MPs ingestion in fish species, with a greater likelihood of ingestion in the cold season and in specimens with higher GSI values (i.e. higher feeding inten sity). Four PAEs (DEP, DIBP, BBP, DEHP) were detected in all the species analysed, with average ∑PAEs concentrations ranging between 10.31 and 30.86 ng/g (wet weight). DIBP was positively correlated with ingested MPs, suggesting this compound might represent a “plastic tracer”. This study looks into the problem of MPs ingestion for pelagic species in an open oceanic region, highlighting the most suitable bioindicators and providing essential insights into the factors that may influence ingestion rates. Additionally, the detection of PAEs in all species indicates the need for further re search on the contamination sources, the effects of these chemicals on marine organisms, and the potential risks to human health through seafood consumption.
- Nutrient deprivation stimulates soluble extracellular polymeric substances: physiological and biochemical responses in the cyanobacterium Cyanocohniella rudolphiaPublication . Rodrigues, Filipa; Mendonça, Ivana; Faria, Marisa; Mougin, Karine; Gómez Pinchetti, Juan Luis; Ferreira, Artur; Cordeiro, Nereida; Gonçalves Rodrigues, Ana Filipa; Silva Mendonça, Ivana Rita da; Faria, Marisa Camacho Gonçalves; cordeiro, nereidaThe effect of macro- and micronutrient deprivation on the cyanobacterium Cyanocohniella rudolphia (BEA 0786B) over 180 days (without medium renewal) was evaluated to intensify the production of soluble extracellular polymeric substances (S-EPS). Growth, pH, cell-free medium viscosity, S-EPS content (phenol‑sulfuric acid assay), Alcian Blue staining, and biochemical/structural markers were monitored to assess EPS release and extracellular matrix dynamics. Progressive nutrient depletion induced a shift from biomass growth toward extracellular-matrix investment. Microcolony formation observed around day 45 preceded a sustained high- production phase, with pronounced matrix densification evident by approximately day 75. Apparent viscosity increased in parallel with S-EPS accumulation and showed a strong correlation with extracellular carbohydrate concentration (R 2 = 0.86), supporting its use as an operational, non-destructive proxy for S-EPS. Alcian Blue staining qualitatively confirmed the presence of acidic polysaccharides. Quantitatively, S-EPS concentrations increased from 0.1 to 0.8 g L 1 , accompanied by an increase in apparent viscosity from 24.7 to 34.7 mPa⋅s. Morphological and spectroscopic analyses indicated a predominantly carbohydrate-rich extracellular matrix with an increasing protein contribution over time. As an exploratory proof of concept, unprocessed S-EPS present in the spent culture medium enabled LAP- initiated photochemical formation of Au and Ag nanoparticles at 365 nm, with S-EPS acting as a stabilising and co-reducing matrix and conferring pH-responsive optical behaviour. This indicates a practical route toward integration into EPS-rich matrices to engineer stimuli-responsive coatings and biomaterials. Overall, this study demonstrates that prolonged nutrient deprivation without medium renewal is an effective strategy to intensify S- EPS accumulation in C. rudolphia and that apparent viscosity provides a practical in-process parameter for monitoring production and supporting direct valorisation of spent culture medium in saline bioprocesses.
- Soluble extracellular polymeric substances and microplastics: exposure-response and circular reuse for removalPublication . Rodrigues, Filipa; Mendonça, Ivana; Faria, Marisa; Gomes, Ricardo; Gómez Pinchetti, Juan L.; Ferreira, Artur; Cordeiro, Nereida; cordeiro, nereidaMicroplastics (MPs) are pervasive in aquatic systems, threatening ecosystems, human health, and microalgal production. Soluble extracellular polymeric substances (S-EPS) can agglomerate particles and aid removal. This study examines S-EPS from the cyanobacterium Cyanocohniella rudolphia (BEA 0786B) to (i) model and optimise S-EPS production, (ii) assess production in water contaminated with polystyrene MPs (PS-MPs), and (iii) test S EPS as a bioflocculant for PS-MPs removal. Response surface methodology (RSM) defined a cost-lean operating window and predicted an optimum S-EPS titre of 113 mg/L at 7 days using 10 g/L nitrogen, 0.98 g/L phosphorus, and a biomass-to-medium ratio of 1:6.87 (w/v). Cultures were challenged with PS-MPs (50 μg/L and 5 mg/L) under static or aerated conditions, and at both exponential and stationary phases, and showed stimulated S-EPS synthesis with increases of up to 34%, depending on hydrodynamics and growth stage. Purified S-EPS were evaluated as a bioflocculant at 2 g/L PS-MPs to probe robustness and rate-limiting mechanisms and to delineate a conservative operating window. Maximum removal of 82% was achieved in freshwater at pH 3.5 with Fe3+ 0.05% (w/w), 25 ◦C, S-EPS dose 400 mg/L (S-EPS:PS-MPs 1:5, w/w), and 60 min flocculation. Zeta potential trends and microscopy support charge neutralisation/bridging as the dominant mechanism. Compatible with standard coagulation/flocculation units, the approach links cost-lean, cultivation-derived S-EPS (typically dis carded) to their reuse as a low-additive pretreatment for algal-cultivation intake waters (freshwater/low salinity), reducing reliance on synthetic coagulants and added salinity/metal-sludge burdens. Overall, C. rudolphia is a promising S-EPS producer, whose production is enhanced by exposure to PS-MPs, and its S-EPS acts as an efficient, bio-based flocculant for PS-MPs. The results support process designs to safeguard microalgal operations and to mitigate microplastic pollution in water. This work integrates RSM-optimised S-EPS produc tion, environmental-level exposure-response, and a high-load removal benchmark, enabling circular, low additive, drop-in pretreatment compatible with standard coagulation/flocculation units.
- Towards scalable production of bound extracellular polymeric substances (B-EPS): autoclave hydrothermal extraction coupled with solvent-free ultrafiltrationPublication . Mendonça, Ivana; Rodrigues, Filipa; Marisa Faria; Gómez Pinchetti, Juan L.; Ferreira, Artur; Cordeiro, Nereida; Silva Mendonça, Ivana Rita da; Gonçalves Rodrigues, Ana Filipa; Faria, Marisa Camacho Gonçalves; cordeiro, nereidaBound extracellular polymeric substances (B-EPS) are extracellular polysaccharides tightly attached to cyanobacterial and microalgal cell surfaces, representing a high-value class of biopolymers with industrial potential. Selective extraction is technically challenging due to strong adhesion to the cell wall and poten tial co-extraction of soluble EPS. Conventional methods can be chemically aggressive and may involve high energy and/or solvent inputs, making solvent-free extraction routes desirable. In this work, four hydrothermal extraction techniques (reflux, autoclave, ultrasonic bath, and microwave) were evaluated for their ability to recover B-EPS from the marine cyanobacterium Chroococcus submarinus (BEA 1200B), followed by a harmonised ultrafiltration step. Each method was assessed for extraction efficiency and its impact on bulk descriptors (inorganic carry-over, ATR-FTIR, zeta potential, and thermal profiles) and mor phology. Among the methods tested, autoclave extraction demonstrated the highest performance, yield ing up to 2.5 times more B-EPS than the other methods and showing reduced inorganic carry-over after purification. Across all methods, the purified B-EPS fractions exhibited broadly comparable bulk profiles under the applied analytics. Response Surface Methodology (RSM) applied to the autoclave system ident ified temperature and extraction time as key variables; optimal conditions (biomass-to-solvent ratio 1:20 (w/v), 130 °C, 16 min) enabled >90% recovery. Coupling autoclave extraction with solvent-free ultrafiltra tion avoids solvent precipitation and the use of hazardous reagents, enabling desalting and removal of low-molecular-weight components. Using a photosynthetic marine strain supports seawater cultivation and biogenic CO2 uptake, aligning the workflow with carbon-mitigation goals.