Browsing by Author "Costa, Margarida"
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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.
- Effects of outdoor and indoor cultivation on the polar lipid composition and antioxidant activity of Nannochloropsis oceanica and Nannochloropsis limnetica: A lipidomics perspectivePublication . Couto, Daniela; Conde, Tiago A.; Melo, Tânia; Neves, Bruna; Costa, Margarida; Cunha, Pedro; Guerra, Inês; Correia, Nádia; Silva, Joana T.; Pereira, Hugo; Varela, João; Silva, Joana; Domingues, Rosário; Domingues, PedroNannochloropsis is a genus of eicosapentaenoic acid-rich microalgae with high levels of value-added polar lipids. However, the polar lipid composition of microalgal biomass is highly dependent on culture conditions (e.g., light or temperature), which are significantly different under indoor and outdoor culture conditions. In this study, we sought to investigate the plasticity of the polar lipid profile of a marine (N. oceanica) and a freshwater (N. limnetica) species of Nannochloropsis grown in indoor and outdoor photobioreactors. To this end, the polar lipidome and fatty acid profiles were characterized by liquid chromatography-mass spectrometry (LC-MS), and gas chromatography-mass spectrometry (GC-MS), respectively. In addition, the antioxidant activity of their lipid extracts was assessed. The highest lipid contents were obtained for the two species grown indoors. LC-MS analysis identified 239 different polar lipid species, of which 220 were shared by all experimental groups. Candidate lipid biomarkers from both culture systems were proposed, including MGDG(34:2), MGDG(34:1) and PG(36:6). For both species, indoor conditions lead to lipid extracts rich in glycolipids and higher in oleic acid content. In contrast, outdoor conditions lead to higher proportions of phospholipids and betaine lipids and a higher relative content of eicosapentaenoic acid (EPA). The polar lipid profile of the two Nannochloropsis species differed primarily in the relative amounts of certain betaine lipids, mainly DGTS (which was increased in N. oceanica) and lysolipids (LPC, and LPE) (increased in N. limnetica), although the majority of lipids were observed in both species. The lipid extracts showed antioxidant activity (IC15) ranging from 30.4 +/- 1.8 to 45.7 +/- 1.6 mu mol Trolox g-1 of lipid extract. Overall, this study provides insight into the lipid metabolic adaptation of two Nannochloropsis species, providing the know-how to obtain a healthy polar lipid-rich biomass useful for novel applications in pharmaceutical, nutraceutical, or novel foods.
- Isolation, identification and biotechnological applications of a novel, robust, free-living Chlorococcum (Oophila) amblystomatis strain isolated from a local pondPublication . Correia, Nádia; Pereira, Hugo; Silva, Joana T.; Santos, Tamara; Soares, Maria; Sousa, Carolina B.; Schüler, Lisa Maylin; Costa, Margarida; J. C. or Varela J. or Varela J.C.S.; Pereira, Leonel; Silva, JoanaBioprospection of novel autochthonous strains is key to the successful industrial-scale production of microalgal biomass. A novel Chlorococcum strain was recently isolated from a pond inside the industrial production facility of Allmicroalgae (Leiria, Portugal). Phylogenetic analysis based on 18S ribosomal ribonucleic acid (rRNA) gene sequences suggests that this isolate is a novel, free-living Oophila amblystomatis strain. However, as our phylogenetic data strongly suggests that the aforementioned taxon belongs to the genus Chlorococcum, it is here proposed to rename this species as Chlorococcum amblystomatis. In order to characterize the biotechnological potential of this novel isolate, growth performance and biochemical composition were evaluated from the pilot (2.5-m3) to industrial (10-m3) scale. The highest maximum areal productivity (36.56 g m2 day1) was reached in a 10-m3 tubular photobioreactor (PBR), as compared to that obtained in a 2.5-m3 PBR (26.75 g m2 day1). Chlorococcum amblystomatis displayed high protein content (48%–56% dry weight (DW)) and moderate levels of total lipids (18%–31% DW), carbohydrates (6%–18% DW) and ashes (9%–16% DW). Furthermore, the lipid profile was dominated by polyunsaturated fatty acids (PUFAs). The highest pigment contents were obtained in the 2.5-m3 PBR, where total chlorophylls accounted for 40.24 mg g1 DW, followed by lutein with 5.37 mg g1 DW. Overall, this free-living Chlorococcum amblystomatis strain shows great potential for nutritional applications, coupling a promising growth performance with a high protein content as well as relevant amounts of PUFAs, chlorophyll, and carotenoids.
- Microalgae as a selenium vehicle for nutrition: a reviewPublication . Pires, Rita; Costa, Margarida; Pereira, Hugo; Cardoso, Helena; Ferreira, Luís; Lapa, Nuno; Silva, Joana; Ventura, MárciaSelenium (Se) is essential for human and animal nutrition, playing a key role in antioxidant and immune functions. Organic Se is better for supplementation because it is more efficiently assimilated and less toxic than its inorganic form. Due to the scarcity of Se in European soils, supplementation in feed and food is necessary. Currently, inorganic Se (sodium selenite and selenate) and organic Se in Se-enriched yeast are approved by the European Food Safety Authority (EFSA) to address Se deficiency. However, Se-enriched microalgae present a promising alternative. By supplementing their growth media with Se, microalgae convert it into organic forms like Se-cysteine and Se-methionine, creating Se-enriched biomass. This biomass can serve as a valuable Se source with the additional benefits of microalgae. This review evaluates the viability of microalgae as a Se supplementation vehicle in food and feed and explores its commercial applications in the European Union (EU), along with emerging projects and innovations in the field.
- Nannochloropsis oceanica cultivation in pilot-scale raceway ponds—from design to cultivationPublication . Cunha, Pedro; Pereira, Hugo; Costa, Margarida; Pereira, João; Silva, Joana T.; Fernandes, Nuno; Varela, João; Silva, Joana; Simões, ManuelRaceways ponds are the microalgal production systems most commonly used at industrial scale. In this work, two di erent raceway configurations were tested under the same processing conditions to compare their performance on the production of Nannochloropsis oceanica. Biomass productivity, biochemical composition of the produced biomass, and power requirements to operate those reactors were evaluated. Water depths of 0.20 and 0.13 m, and culture circulation velocities of 0.30 and 0.15 m s1 were tested. A standard configuration, which had a full channel width paddlewheel, proved to be the most energy e cient, consuming less than half of the energy required by a modified configuration (had a half channel width paddlewheel). The later showed to have slightly higher productivity, not enough to o set the large di erence in energetic consumption. Higher flow velocity (0.30 m s1) led to a 1.7 g m2 d1 improvement of biomass productivity of the system, but it increased the energy consumption twice as compared to the 0.15 m s1 flow velocity. The latter velocity showed to be the most productive in lipids. A water depth of 0.20 m was the most suitable option tested to cultivate microalgae, since it allowed a 54% energy saving. Therefore, a standard raceway pond using a flow velocity of 0.3 m s1 with a 0.20 m water depth was the most e cient system for microalgal cultivation. Conversely, a flow velocity of 0.15 m s1 was the most suitable to produce lipids.
- Operation regimes: A comparison based on Nannochloropsis oceanica biomass and lipid productivityPublication . Guerra, Inês; Pereira, Hugo; Costa, Margarida; Silva, Joana T.; Santos, Tamara; Varela, João; Mateus, Marília; Silva, JoanaMicroalgae are currently considered to be a promising feedstock for biodiesel production. However, significant research efforts are crucial to improve the current biomass and lipid productivities under real outdoor production conditions. In this context, batch, continuous and semi-continuous operation regimes were compared during the Spring/Summer seasons in 2.6 m(3) tubular photobioreactors to select the most suitable one for the production of the oleaginous microalga Nannochloropsis oceanica. Results obtained revealed that N. oceanica grown using the semi-continuous and continuous operation regimes enabled a 1.5-fold increase in biomass volumetric productivity compared to that cultivated in batch. The lipid productivity was 1.7-fold higher under semi-continuous cultivation than that under a batch operation regime. On the other hand, the semi-continuous and continuous operation regimes spent nearly the double amount of water compared to that of the batch regime. Interestingly, the biochemical profile of produced biomass using the different operation regimes was not affected regarding the contents of proteins, lipids and fatty acids. Overall, these results show that the semi-continuous operation regime is more suitable for the outdoor production of N. oceanica, significantly improving the biomass and lipid productivities at large-scale, which is a crucial factor for biodiesel production.