Percorrer por autor "Trovão, Mafalda"
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- Development of an organic culture medium for autotrophic production of chlorella vulgaris biomassPublication . Machado, Adriana; Pereira, Hugo; Costa, Margarida; Santos, Tamara; Carvalho, Bernardo; Soares, Maria; Quelhas, Pedro; Silva, Joana T.; Trovão, Mafalda; Barros, Ana; Varela, João; Vicente, António A.; Silva, JoanaMicroalgal biomass has gained increasing attention in the last decade for various biotechnological applications, including human nutrition. Certified organic products are currently a growing niche market in which the food industry has shown great interest. In this context, this work aimed at developing a certified organic culture medium for the production of autotrophic Chlorella vulgaris biomass. A preliminary assay in 2 L bubble column photobioreactors was performed in order to screen di erent commercial organic substrates (OS) at a normalized concentration of N (2 mmol L1). The highest growth performance was obtained using EcoMix4 and Bioscape which showed similar biomass concentrations compared to the synthetic culture medium (control). In order to meet the nutrient needs of Chlorella, both OS underwent elemental analyses to assess their nutrient composition. The laboratory findings allowed the development of a final organic culture medium using a proportion of Bioscape/EcoMix4 (1:1.2, m/m). This organic culture medium was later validated outdoors in 125 L flat panel and 10 m3 tubular flow through photobioreactors. The results obtained revealed that the developed organic medium led to similar microalgal growth performance and biochemical composition of produced biomass, as compared to the traditional synthetic medium. Overall, the formulated organic medium was e ective for the autotrophic production of organic C. vulgaris biomass.
- Growth performance, biochemical composition and sedimentation velocity of Tetraselmis sp. CTP4 under different salinities using low-cost lab- and pilot-scale systemsPublication . Trovão, Mafalda; Pereira, Hugo; Silva, Joana; Páramo, Jaime; Quelhas, Pedro; Santos, Tamara; Silva, Joana T.; Machado, Adriana; Gouveia, Luísa; Barreira, Luísa; Varela, JoãoBiomass harvesting is one of the most expensive steps of the whole microalgal production pipeline. Therefore, the present work aimed to understand the effect of salinity on the growth performance, biochemical composition and sedimentation velocity of Tetraselmis sp. CTP4, in order to establish an effective low-cost pilot-scale harvesting system for this strain. At lab scale, similar growth performance was obtained in cultures grown at salinities of 5, 10 and 20 g L-1 NaCl. In addition, identical settling velocities (2.4-3.6 cm h-1) were observed on all salinities under study, regardless of the growth stage. However, higher salinities (20 g L-1) promoted a significant increase in lipid contents in this strain compared to when this microalga was cultivated at 5 or 10 g L-1 NaCl. At pilot-scale, cultures were cultivated semi-continuously in 2.5-m3 tubular photobioreactors, fed every four days, and stored in a 1-m3 harvesting tank. Upon a 24-hour settling step, natural sedimentation of the microalgal cells resulted in the removal of 93% of the culture medium in the form of a clear liquid containing only vestigial amounts of biomass (0.07 ± 0.02 g L-1 dry weight; DW). The remaining culture was recovered as a highly concentrated culture (19.53 ± 4.83 g L-1 DW) and wet microalgal paste (272.7 ± 18.5 g L-1 DW). Overall, this method provided an effective recovery of 97% of the total biomass, decreasing significantly the harvesting costs.
- Heterotrophic cultivation of Chlorella vulgaris yellow mutant on sidestreams: Medium formulation and process scale-upPublication . Trovão, Mafalda; Barros, Ana; Machado, Adriana; Reis, Ana; Pedroso, Humberto; Espírito Santo, Gonçalo; Correia, Nádia; Costa, Monya; Ferreira, Sara; Varela, João; Cardoso, Helena; Silva, Joana; Pereira, Hugo; Freitas, FilomenaMicroalgal protein is a promising feedstock to complement and/or replace other protein sources. Besides requiring less land and water usage, microalgae production is a more sustainable process, especially if industrial sidestreams are used as nutrient sources. Additionally, the heterotrophic cultivation of microalgae, such as Chlorella vulgaris, enables the achievement of much higher biomass productivity and lower areal footprint than autotrophic cultivation. Chlorophyll-deficient strains of C. vulgaris, as the yellow strain 7Y, provide microalgal biomass with improved sensory properties. In line with this, a waste-based medium was formulated to cultivate this strain, aiming at maximum biomass productivity. In this context, several industrial sidestreams were screened, and two food wastes and corn molasses were selected for their high nitrogen and glucose concentrations, respectively. The waste-based medium formulated was compared to the inorganic optimised medium at laboratory scale in Erlenmeyer flasks and 7-L reactors. The results obtained in the 7-L fermenters revealed that both conditions achieved similar biomass productivities and growth rates of approximately 14 g L-1 d-1 and 0.8 d-1, respectively. The biomass and protein productivities were further enhanced by supplying a higher nitrogen concentration in the feeding solution when the process was scaled-up to 200-L reactors, reaching 22 and 6.3 g L-1 d-1, respectively, thus validating the developed industrial waste-based medium for the efficient cultivation of C. vulgaris under heterotrophic conditions.
- Impact of seasons on industrial cultivation of Limnospira platensis (Spirulina): a year-round case study on biomass, phycocyanin, and protein productivity in PortugalPublication . Guerra, Inês; Torres, Cátia; Cardoso, Helena; Pereira, Hugo; Trovão, Mafalda; Rodrigues, Alexandre M. C.; Varela, JoãoSpirulina is the most commercially produced biomass, among microalgae and cyanobacteria, with extensive applications across food, feed, nutraceutical and biotechnological sectors. While Spirulina cultivation is wellcharacterized at laboratorial and small-scale production, critical knowledge gaps remain regarding industrialscale production in temperate climates. Specifically, there is a lack of robust empirical data on how seasonal environmental fluctuations affect year-round productivity and the maintenance of consistent biomass quality (protein, phycocyanin content) under large-scale operational constraints. This study evaluates the year-round industrial production of Limnospira platensis in large-scale (1000 m2 and 4000 m2 ) raceway reactors at Allmicroalgae - Natural Products S.A., Portugal. Biomass productivity as well as protein and phycocyanin contents across different seasons and throughout the day were assessed. The influence of environmental factors such as temperature and solar radiation on productivity and biomass composition was also analyzed. Industrially grown Spirulina reached an average annual productivity of 5.1–5.6 g.m− 2 .d− 1 . Seasonal variation revealed a winter productivity decline higher than 60 %, compared to peak yields of 7.5–7.6 g.m− 2 .d− 1 from April to September. Protein content remained consistent year-round between 58.4 and 64.7 %, whereas phycocyanin content presented strong solar radiation dependence, peaking at 15.2 % in summer and decreasing to 10.4 % in winter. Furthermore, an analysis throughout the day identified an optimal harvesting window between midday and sunset to maximize phycocyanin levels. These findings validate the industrial feasibility of year-round Spirulina cultivation in temperate climates and provide seasonal productivity forecasting and harvest timing optimization, towards protein consistency and phycocyanin yield optimization.
- Isolation and characterization of novel chlorella vulgaris mutants with low chlorophyll and improved protein contents for food applicationsPublication . Lisa Schueler, Lisa M. Schueler; Morais, Etiele Greque de; Trovão, Mafalda; Machado, Adriana; Carvalho, Bernardo; Carneiro, Mariana; Maia, Inês; Soares, Maria; Duarte, Paulo; Barros, Ana; Pereira, Hugo; Silva, Joana; Varela, JoãoMicroalgae are widely used as food supplements due to their high protein content, essential fatty acids and amino acids as well as carotenoids. The addition of microalgal biomass to food products (e.g., baked confectioneries) is a common strategy to attract novel consumers. However, organoleptic factors such as color, taste and smell can be decisive for the acceptability of foods supplemented with microalgae. The aim of this work was to develop chlorophyll-deficient mutants of Chlorella vulgaris by chemically induced random mutagenesis to obtain biomass with different pigmentations for nutritional applications. Using this strategy, two C. vulgaris mutants with yellow (MT01) and white (MT02) color were successfully isolated, scaled up and characterized. The changes in color of MT01 and MT02 mutant strains were due to an 80 and 99% decrease in their chlorophyll contents, respectively, as compared to the original wild type (WT) strain. Under heterotrophic growth, MT01 showed a growth performance similar to that of the WT, reaching a concentration of 5.84 and 6.06 g L-1, respectively, whereas MT02 displayed slightly lower growth (4.59 g L-1). When grown under a light intensity of 100 μmol m-2 s-1, the pigment content in MT01 increased without compromising growth, while MT02 was not able to grow under this light intensity, a strong indication that it became light-sensitive. The yellow color of MT01 in the dark was mainly due to the presence of the xanthophyll lutein. On the other hand, phytoene was the only carotenoid detected in MT02, which is known to be colorless. Concomitantly, MT02 contained the highest protein content, reaching 48.7% of DW, a 60% increase as compared to the WT. MT01 exhibited a 30% increase when compared to that of the WT, reaching a protein content of 39.5% of DW. Taken together, the results strongly suggest that the partial abrogation of pigment biosynthesis is a factor that might promote higher protein contents in this species. Moreover, because of their higher protein and lower chlorophyll contents, the MT01 and MT02 strains are likely candidates to be feedstocks for the development of novel, innovative food supplements and foods.
- Lab-scale optimization of aurantiochytrium sp. culture medium for improved growth and DHA productionPublication . Trovão, Mafalda; Pereira, Hugo; Costa, Margarida; Machado, Adriana; Barros, Ana; Soares, Maria; Carvalho, Bernardo; Silva, Joana Teles; Varela, João; Silva, JoanaThraustochytrids have gained increasing relevance over the last decades, due to their fast growth and outstanding capacity to accumulate polyunsaturated fatty acids (PUFAs), particularly docosahexaenoic acid (DHA). In this context, the present work aimed to optimize the growth performance and DHA yields by improving the culture medium of Aurantiochytrium sp. AF0043. Accordingly, two distinct culture media were optimized: (i) an inorganic optimized medium (IOM), containing only monosodium glutamate and glucose as nitrogen and carbon sources, respectively; and (ii) an organic and sustainable waste-based optimized medium (WOM), containing corn steep powder and glycerol, added in fed-batch mode, as nitrogen and carbon sources, respectively. Overall, the lab-scale optimization allowed to increase the biomass yield 1.5-fold and enhance DHA content 1.7-fold using IOM. Moreover, WOM enabled a 2-fold increase in biomass yield and a significant improvement in lipid contents, from 22.78% to 31.14%. However, DHA content was enhanced almost 3-fold, from an initial content of 10.12% to 29.66% of total fatty acids contained in the biomass. Therefore, these results strongly suggest, not only that the production pipeline was significantly improved but also confirmed the potential use of Aurantiochytrium sp. AF0043 as a source of DHA.