Percorrer por autor "Sousa, Ana Sofia da Silva"
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- Arthrobacter nicotinovorans EAPAA enhances must attributes: evidence from Spanish and Portuguese case studiesPublication . Sousa, Ana Sofia da Silva; Prieto Fernández, Ángeles; Trasar-Cepeda, Carmen; Castro, Paula; Pereira, Sofia Isabel AlmeidaBackground: Mediterranean agriculture faces severe challenges from soil degradation and water scarcity, intensified climate change, and unsustainable practices, like the overuse of chemicals. These pressures drive biodiversity loss, soil erosion, and declining crop productivity, threatening food security and farming’s long-term viability. Enhancing resilience in agri-food systems requires the combination of sustainable agronomic practices and innovative biotechnological solutions. Among these, the use of plant-growth-promoting bacteria (PGPB) is a currently sought strategy to support crop performance. Despite their proven benefits under controlled conditions, it is essential to widen the assessment of PGPB robustness and stability in real-world situations. Methods: Two case studies in Ribeiro (Spain) and Douro (Portugal) evaluated the effects of Arthrobacter nicotinovorans EAPAA inoculation on grapevine (Vitis vinifera L.), focusing on must quality and soil properties. The strain EAPAA has been shown to enhance P solubilization and N2 fixation. Field trials covered an average area of 300 m2 in Spain and 600 m2 in Portugal. Results: Must composition analysis show that inoculation significantly affected sugars and organic acid levels in both sites. In Spain, inoculation increased glucose and fructose by 18% and 31%, respectively; tartaric and malic acid by 17.5% and 9.2%, respectively, and succinic acid by 29.8%- 71.3%, alongside higher soil P available, labile C compounds, and biological activity. In Portugal, sugars increased by 33% and tartaric and malic acids by 50%, improvements that directly influence the quality of the wine. Conclusion: This study demonstrates the adaptability of A. nicotinovorans EAPAA and its beneficial effects on both must quality and soil health.
- Bio-based superabsorbent hydrogels for nutrient releasePublication . Ribeiro, Alessandra B.; Moreira, Helena; Pereira, Sofia I. A.; Godinho, Mariana; Sousa, Ana Sofia da Silva; Castro, Paula; Pereira, Carla F.; Casanova, Francisca; Freixo, Ricardo; Pintado, Manuela E.; Ramos, Óscar L.Drought is characterized by a low water precipitation rate, with strong impact on crop productivity, threatening global food production. In this context, the use of soil amendments, such as superabsorbent hydrogels constitute a potential technology for better water use efficiency and higher crop yields. In this work, we synthesised cellulose-based hydrogels, characterized their physical and functional properties, evaluated their impact on the environment, and their potential to be used as a soil amendments. The hydrogel showed pH of 6.0 to 7.5 and conductivity below 10.0 µS cm-1. The Fourier-transform infrared spectroscopy (FTIR) showed a low intensity peak in the crystallinity region, which was supported by the low crystallinity index (27.3% ± 0.6) verified by Powder X-ray diffraction (PXRD) analysis. The swelling capacity reached more than 200 g of water, the hydrogel showed good resistance to osmotic pressure and high thermostability, which favours the application in hot and arid areas. In addition, no potentially hazardous compound was detected, nor was there any adverse effect on soil microorganisms. Further, the hydrogel was found to be safe for use during seed sowing and for promoting seedling development. In the greenhouse pot experiment, the hydrogels showed a significant increase in maize shoot and root biomass, demonstrating their ability to contribute to the overall water holding capacity of the soil, thereby influencing nutrient availability for more efficient plant growth. In conclusion, the superabsorbent hydrogel exhibited promising characteristics for use as a soil amendment, scalability potential and constitutes a sustainable alternative for agricultural applications.
- Food processing wastewater as feedstock for microalgae growth and nutrient removalPublication . Sousa, Ana Sofia da Silva; Amorim, Catarina Raquel Leite; Castro, Paula Maria Lima e; Oliveira, Ana TeixeiraA indústria da carne é responsável por gerar volumes elevados de água residual proveniente do processamento de carne (ARPC), altamente carregada em termos de nutrientes, carbono e sólidos suspensos. O seu descarte sem tratamento diminui a qualidade da superfície da água, podendo levar à morte da vida aquática e à eutrofização. Atualmente, o interesse na utilização de microalgas para tratar ARPC tem aumentado, assim como no potencial da sua utilização como um produto de base biológica, integrando o processo de tratamento no conceito de economia circular. Neste estudo, a capacidade de um consórcio de microalgas tratar e crescer em ARPC sem pré-tratamento foi avaliada. A caracterização da ARPC de diferentes ciclos de produção revelou uma variabilidade elevada na sua composição em carbono e nutrientes. A viabilidade em tratar ARPC sem pré-tratamento, bem como a influência da comunidade microbiana nativa e do material sólido presentes na ARPC na remoção de nutrientes e crescimento de biomassa foram avaliadas. A água residual foi recolhida de uma fábrica de processamento de carne e era composta por uma mistura de água residual preveniente da lavagem dos bombos de cozedura e de água utilizada no processo de arrefecimento (1:1). O cultivo do consórcio em ARPC foi realizado em diferentes condições e a remoção de nutrientes e carbono, bem como o crescimento da biomassa, foram monitorizados durante o cultivo. O cultivo do consórcio em água residual sem pré-tratamento e em água residual esterilizada permitiu avaliar que a taxa de remoção da carência química de oxigénio da comunidade microbiana nativa da ARPC foi de 125,9 mg L-1 dia-1 nos primeiros oito dias, mas, na presença do consórcio de microalgas, a taxa de remoção aumentou para 138,3 mg L-1 dia-1. Como a ARPC foi utilizada sem nenhum pré-tratamento, em todas as condições testadas observou-se um aumento do azoto total e ião amónio talvez devido à dissolução dos sólidos suspensos. O crescimento da biomassa foi maior no cultivo com ARPC sem pré-tratamento do que com a esterilizada, provavelmente devido ao efeito sinérgico estabelecido entre as duas comunidades. A remoção de carbono e o crescimento das microalgas não foram afetados negativamente pela presença de sólidos, sustentando a hipótese de que a ARPC pode ser utilizada para a produção de biomassa sem a necessidade de tratamento prévio, sendo potencialmente mais viável economicamente. A análise molecular dos isolados de microalgas cultiváveis revelou que estes pertencem a dois géneros da classe Trebouxiophyceae, Micractinium e Chlorella.
- Innovative PGPB-based fertilizers as a sustainable solution to promote crop resilience in degraded soilsPublication . Sousa, Ana Sofia da Silva; Epelde, Lur; Alves, Paulo Célio; Castro, Paula M. L.; Pereira, Sofia I. A.Background: Biofertilizers, made of non-pathogenic and living microorganisms, such as plant growth-promoting bacteria (PGPB), support crop growth in degraded soils as eco-friendly alternatives to chemical fertilizers. They enhance nutrient availability, reduce pollution, and boost stress resilience. However, field performance and effectiveness remain inconsistent due to short shelf life, low bacterial viability, and unstable trait expression. This study aims to perform a comprehensive laboratory study by testing a novel biofertilizer carrier to ensure long-term efficiency, along with a proper selection of bacterial strains based on a greenhouse pot assay. Methods: Fifty-three representative bacteria were isolated from soil samples collected in Alentejo for assessment of traits such as P solubilization, N2 fixation, osmotic stress tolerance, and production of lytic enzymes, siderophores, and extracellular polymeric substances (EPS). A greenhouse pot experiment using wheat is ongoing to test the real ability of each isolate to influence plant growth under water stress conditions. A PGPB-based formulation using a new carrier, EPS, a gel-like polymer that confers protection to microbial cells, is being developed, making use of the most promising isolates. Results: Among the isolates, 30% showed the ability to solubilize P, 54.4% to fix N2, and 62.3%, 37.7%, and 18.9% to produce proteases, pectinases, and cellulases, respectively. 16S rRNA isolates sequencing revealed the presence of genera such as Bacillus, Pedobacter, and Streptomyces. Dried EPS was mixed with a concentrated bacterial suspension, and granules were produced. Granule’s physical resistance and bacterial viability tests are being carried out. Conclusions: This approach will support the development of a robust formulation with strong potential for success.