Browsing by Author "Pereira, Ana M."
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- An eco-friendly and up-scalable approach to extract canthaxanthin from yeast cellsPublication . Pereira, Ana M.; Durão, Joana; Pereira, Joana Odila; Ferreira, Carlos; Faustino, Margarida; Oliveira, Ana Sofia; Pereira, Carla F.; Pintado, Manuela E.; Carvalho, Ana P.Canthaxanthin is a naturally occurring ketocarotenoid pigment present in plants, algae, bacteria and some fungi. In addition to its coloring role, canthaxanthin has an excellent antioxidant activity, thus having additional market demands in the feed, food, cosmetic and pharmaceutical industries. Canthaxanthin can be directly isolated from its natural source or produced by chemical synthesis, but these strategies either result in low yields, or use hazardous solvents, respectively. Therefore, the biosynthesis of canthaxanthin using microbial cell factories is becoming an advantageous alternative. Furthermore, microbial synthesis represents an economic and sustainable approach as it enables the use of agriculture and industrial wastes as substrates. In this work, the extraction, recovery and purification of canthaxanthin from modified yeasts using food grade solvents and up-scalable methodologies was studied. The resulting canthaxanthin-enriched extract was characterized (UV-Vis, PXRD and SEM) and quantified (HPLC), resulting in a canthaxanthin purity of 43.7 % (w/w).
- Comparative analysis of mannans extraction processes from spent yeast saccharomyces cerevisiaePublication . Faustino, Margarida; Durão, Joana; Pereira, Carla F.; Oliveira, Ana Sofia; Pereira, Joana Odila; Pereira, Ana M.; Ferreira, Carlos; Pintado, Manuela E.; Carvalho, Ana P.Mannans are outstanding polysaccharides that have gained exponential interest over the years. These polysaccharides may be extracted from the cell wall of Saccharomyces cerevisiae, and recovered from the brewing or synthetic biology industries, among others. In this work, several extraction processes—physical, chemical and enzymatic—were studied, all aiming to obtain mannans from spent yeast S. cerevisiae. Their performance was evaluated in terms of yield, mannose content and cost. The resultant extracts were characterized in terms of their structure (FT-IR, PXRD and SEM), physicochemical properties (color, molecular weight distribution, sugars, protein, ash and water content) and thermal stability (DSC). The biological properties were assessed through the screening of prebiotic activity in Lactobacillus plantarum and Bifidobacterium animalis. The highest yield (58.82%) was achieved by using an alkaline thermal process, though the correspondent mannose content was low. The extract obtained by autolysis followed by a hydrothermal step resulted in the highest mannose content (59.19%). On the other hand, the extract obtained through the enzymatic hydrolysis displayed the highest prebiotic activity. This comparative study is expected to lay the scientific foundation for the obtention of well-characterized mannans from yeast, which will pave the way for their application in various fields.
- A step for the valorization of spent yeast through production of iron–peptide complexes — a process optimization studyPublication . Ferreira, Carlos; Pereira, Carla F.; Oliveira, Ana Sofia; Faustino, Margarida; Pereira, Ana M.; Durão, Joana; Pereira, Joana Odila; Pintado, Manuela E.; Carvalho, Ana P.Given the importance of iron in human nutrition and the significance of waste and by-product valorisation in a circular economy environment, we investigated the effects of protein and iron concentration on the production yield of iron–peptide complexes from spent Saccharomyces cerevisiae. For this purpose, different amounts of protein and iron were used in the complexation process. The results have shown that higher concentrations, although permitting a faster and larger scale process, provide a significantly lower complexation yield, which deems the process less feasible. This is corroborated by fluorescence analysis, which shows a lower degree of complexation with higher protein concentration. In addition, varying the concentration of iron does not change the quality of formed complexes, as evidenced by Fourier transform infrared spectroscopy (FT-IR) analysis. The morphology of all samples was also evaluated using scanning electron microscopy (SEM). Therefore, further studies are needed to optimize the process and to evaluate the best conditions for an economically sound valorization process for iron–peptide complexes. Nonetheless, current results in the development of a new process for the valorisation of spent yeast, in the form of iron-peptide complexes, look promising.
- Urban forest governance: future - the 100,000 trees project in the Porto Metropolitan AreaPublication . Pinto, Marta; Almeida, Conceição; Pereira, Ana M.; Silva, MargaridaThe Porto Metropolitan Area is a region in northern Portugal with approximately 2000 km2. Almost 16 % of the Portuguese population lives in the area, which is structured around the municipality of Porto with 16 other municipalities included. The region is a jigsaw puzzle of urban, agricultural, and forest areas. The Porto Metropolitan Area Environmental Strategic Plan, a broad participatory regional planning process conducted from 2003 to 2008, concluded that major challenges ahead included the improvement of the green infrastructure (forest, riverside areas, and natural corridors), the need for education and training for sustainability, as well as more and better interinstitutional coordination. In order to tackle these vital regional issues several institutions, partners within the framework of the Porto Metropolitan Area Regional Centre of Expertise on Education for Sustainable Development, decided to collaborate in order to design and implement a flagship project. The FUTURE—the 100,000 trees project in the Porto Metropolitan Area is the outcome of this process. Its purpose is to create, restore and care for native urban forests in the region with active involvement of the main stakeholders (landowners, citizens, local governments, central government, companies, non-governmental organisations, and schools, among others). Our aim is to present the case study of this project describing its context, scale, institutional framework, actors and partnerships, resources and processes, highlighting its governance model.