Browsing by Author "Freitas, Ana"
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- Carbon nanotube field effect transistor biosensor for the detection of toxins in seawaterPublication . Marques, Inês; Costa, João Pinto da; Justino, Celine; Santos, Patrícia; Duarte, Kátia; Freitas, Ana; Cardoso, Susana; Duarte, Armando; Rocha-Santos, TeresaDisposable field effect transistors (FET) biosensors (bio-FET) based on carbon nanotubes were fabricated for detection of domoic acid (DA), which belongs to the group of biotoxins associated with the amnesic shellfish poisoning. The analytical results obtained with the bio-FET were compared with those obtained with a traditional methodology (enzyme-linked immunosorbent assay) in order to validate the bio-FET for DA detection. Standard solutions of DA with concentrations between 10 and 500 ng L−1 were tested in order to construct the calibration curve, where five bio-FET were used for reproducibility estimation and two analytical measurements were performed for each bio-FET for repeatability estimation. Ten spiked artificial seawater samples were used to validate the bio-FET. The obtained reproducibility (0.52–1.43%), repeatability (0.57–1.27%), limit of detection (10 ng L−1) and recovery range (92.3–100.3%) reveal an adequate analytical performance of the bio-FET for the detection of DA in environmental samples such as seawater samples.
- Determination of soluble and insoluble dietary fiber content of marine macroalgae and microalgaePublication . Nova, Paulo; Martins, Ana Pimenta; Silva, Joana Gabriela; Pereira, Rui; Abreu, Helena; Silva, Ana Machado; Freitas, Ana; Gomes, Ana
- Production of marine probiotic bacteria in a cost-effective marine media based on peptones obtained from discarded fish by-productsPublication . Vázquez, José Antonio; Durán, Ana; Nogueira, Margarita; Menduíña, Araceli; Antunes, Joana; Freitas, Ana; Gomes, Ana MariaThe industrial production of marine bacteria with probiotic properties is limited by the excessive cost of the culture media adequate for their growth. The present work aimed to study the suitability of 30 marine media formulated with nitrogen sources (fish peptones) from different fish discards and seawater, for the growth of two marine probiotic bacteria (MPB), namely Phaeobacter sp. and Pseudomonas fluorescens. These fish peptones were produced from several discarded fish and by-products (heads, skins, and whole individuals of megrim, mackerel, gurnard, hake, etc.). In all cultivations, no significant differences were found on cell viability when the microorganism grew on commercial or alternative media. In relation to the biomass production, the growth of Phaeobacter sp. on waste media was commonly similar or a 20% lower than observed in the control cultures. For P. fluorescens, various peptones (skin peptones of pouting and blue whiting) showed even higher productive ability than commercial peptones. An initial economical evaluation revealed that low-cost media reduced until 120 times the cost of production of MPB.
- Strategies to increase Akkermansia muciniphila viability during simulated gastrointestinal conditions and stability storagePublication . Freitas, Ana; Almeida, Diana; Machado, Daniela; Mendo, Sónia; Andrade, José; Gomes, Ana