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- Exploring Pavlova pinguis and Hemiselmis cf. andersenii as natural sources of high-value lipidsPublication . Fernandes, Tomásia Micaela Gomez; Cordeiro, Nereida Maria AbanoA crescente demanda dos consumidores por fontes naturais e sustentáveis de compostos de valor acrescentado tem levado as comunidades científica e industrial a explorar a biodiversidade das microalgas e a sua diversidade química. Na bioprospecção de microalgas para a produção integrada de biomassa e compostos de valor acrescentado, diversos desafios são encontrados, como o cultivo de novas espécies, a identificação de novas moléculas e a otimização das condições de cultivo para a produção dos fitoquímicos desejados. Este estudo investiga o potencial de duas microalgas inexploradas, Hemiselmis cf. andersenii e Pavlova pinguis, como fontes de lípidos com valor acrescentado para aplicação na indústria nutracêutica e áreas relacionadas. A análise dos extratos lipídicos revelou uma grande diversidade de metabolitos sintetizados pela H. cf. andersenii e pela P. pinguis, nomeadamente ácidos gordos, esteróis, álcoois e monoglicerídeos. H. cf. andersenii demonstrou ser rica em ómega-3 polinsaturados. Enquanto, a P. pinguis revelou ser uma grande produtora de fitoesteróis. Para verificar a robustez das microalgas e induzir a acumulação dos compostos desejados, foram realizados estudos com diferente suplementação de azoto e de fósforo no meio de crescimento das microalgas. As condições repletas de azoto revelaram-se eficazes para modelar a composição lipídica das microalgas para as indústrias nutracêutica e farmacêutica. Aumentos dos teores de fósforo induziram um aumento da produtividade da biomassa e da produção de lípidos nutricionalmente relevantes. Na P. pinguis, baixos teores de fósforo mostraram-se eficazes para a produção de carotenoides e açúcares. A H. cf. andersenii mostrou-se promissora para a coprodução de carotenoides e lípidos. A análise multivariada permitiu visualizar os efeitos intra e interespecíficos dos nutrientes na composição lipídica das microalgas. A grande versatilidade de compostos de valor acrescentado produzidos pelas microalgas estudadas aliadas às suas características biológicas (ausência de parede celular rígida), fazem destas candidatas promissoras para futura produção à escala industrial.
- Comparative lipidomic analysis of Chlorella stigmatophora and Hemiselmis cf. andersenii in response to nitrogen-induced changesPublication . Fernandes, Tomásia; Ferreira, Artur; Cordeiro, NereidaThe current focus of algae biotechnology is the production of high-value lipids, and its improvement by employing abiotic perturbations such as nitrogen-induced changes. In the present study, the growth dynamics, nitrogen uptake, pigments, and lipid composition of Chlorellla stigmatophora and Hemiselmis cf. andersenii were studied, in response to low (LN), medium (MN) and high (HN) nitrogen supplementations. Both microalgae responded to increased nitrogen levels by increasing their nitrogen uptake rate and pigment content. However, for lipid accumulation, C. stigmatophora presented a different pattern (LN: 16.56% > MN: 11.51% > HN: 10.95%) to that of H. cf. andersenii (MN: 15.37% > HN: 13.06% > LN: 6.71%). Untargeted gas chromatography–mass spectrometry analysis allowed the visualization of the biochemical diversity of C. stigmatophora and H. cf. andersenii, as well as differences in lipid regulation upon nitrogen-induced changes among species. For instance, glycosyl sterols were only detected for C. stigmatophora samples grown under MN and HN conditions. Moreover, lipid analysis of H. cf. andersenii, before and after alkaline hydrolysis, suggests that wax esters play a key role in the response of this microalga to high nitrogen levels. The cultivation of H. cf. andersenii at MN and HN was shown to be ideal for providing a rich source of ω3 and polyunsaturated fatty acids for nutraceutical purposes. The hierarchical cluster analysis showed the differential intra- and interspecific effects of nitrogen on lipid composition. The diverse ways by which both microalgae responded to nitrogen-induced changes highlighted the influence of phylogeny on the carbon flux through metabolic networks, and accumulation.
- Nutritional value and fatty acid profile of two wild edible limpets from the Madeira ArchipelagoPublication . Fernandes, Igor; Fernandes, Tomásia; Cordeiro, NereidaPatella aspera and Patella candei are two abundant limpet species commercially exploited and often used as a delicacy in the Madeira Archipelago, but there is a lack of scientific knowledge about these species. This study investigated the nutritional value and fatty acids of this species across the coast of Madeira Archipelago. The lipid content (7.71–12.60% dw), proteins (48.22–64.09% dw), ashes (11.12–23.12% dw) and carbohydrates (4.5–10.9% dw) were determined in P. aspera and P. candei at different collection sites. In the fatty acid composition, a total of 23 fatty acids (FAs) were identified. P. aspera showed the highest amount of monounsaturated FAs (MUFAs, 35.02%) and eicosapentaenoic acid (EPA, 12.59%), and P. candei presented the highest level of oleic acid (OA, 28.25%), polyunsaturated FAs (PUFAs, 27.26%) and arachidonic acid (AA, 11.38%). The Σω3/Σω6 dietary ratio presented levels>0.25 suggesting that these marine molluscs are a good source of ω3 for dietary intake. Within each specie significant differences (p<0.05) across sites were observed. High amounts of essential nutrients were shown in Patella species collected at Selvagens site while poorest levels were shown in Patella collected at Lido. The evaluation of the nutritional traits of P. candei and P. aspera shows that these limpets are good sources of essential fatty acids for human health and that the distribution of limpets is a key factor when determining its dietary value.
- Effects of phosphorus-induced changes on the growth, nitrogen uptake, and biochemical composition of Pavlova pinguis and Hemiselmis cf. anderseniiPublication . Fernandes, Tomásia; Cordeiro, NereidaThe understanding of the phosphorus-induced changes in the biochemical composition of microalgae is of great importance for achieving efciency in high-value lipid production. To study the chemoplasticity of Pavlova pinguis (Haptophyceae) and Hemiselmis cf. andersenii (Cryptophyceae), their growth, carotenoid and chlorophyll a content, and their monosaccharide and lipid profles were analyzed against several phosphorus (P) regimes: low (LP), medium (MP), and high (HP). For both microalgal cultures, increasing initial P concentrations showed a positive efect on biomass productivities. Carbon-rich pools presented signifcant diferences (p<0.05) for P. pinguis against P treatments, in contrast to H. cf. andersenii. Diferential responses to P-induced changes in microalgae monosaccharide and lipid profle were observed. Hemiselmis cf. andersenii increased its proportion in galactose (up to 3 times) from LP to HP conditions, whereas P. pinguis decreased (up to 20%) its glucose proportion from LP to HP conditions. For P. pinguis, the lowest amount (13.12 mg g−1 dw) of sterols was observed at LP conditions, in contrast to its carotenoid content (4.32 mg g−1 dw). P-replete conditions were the most efective in induc ing high-value lipid accumulation. Non-targeted lipid analysis revealed which samples would need to be processed to fully exploit its high-value lipids, namely H. cf andersenii under MP and HP conditions. This study demonstrated that P played an important role in carbon allocation, nitrogen uptake, and lipid regulation on P. pinguis and H. cf. andersenii, and that P-replete conditions could be useful for optimizing high-value lipids with potential for nutraceutical and pharmaceutical felds.
- Lipid and fatty acid composition of wild Almaco Jack Seriola rivoliana at two maturation stagesPublication . Fernandes, Igor; Nogueira, Natacha; Faria, Graça; Fernandes, Tomásia; Faria, Marisa; Cordeiro, NereidaAlmaco jack (Seriola rivoliana) is an emergent marine finfish that presents high market value. In order to study the feasibility of the exploitation of this marine resource for human consumption the evaluation of the nutritional characteristics of this species has attracted the attention of the scientific community. The lipid characteristics and fatty acid composition were evaluated in muscle, liver and gonad tissues of wild Almaco jack from Atlantic Ocean at two different maturation stages. According to results, the lipid content was found higher at pre-spawning stage (21.78 - 36.17%) and highest proportion being exhibited in the liver. Palmitic acid was predominant among the saturated fatty acids (35.42 - 47.80%) and oleic acid was detected as the main monounsaturated acid (25.26 - 36.55%). Higher amounts of ω3 polyunsaturated fatty acids (PUFAs) were identified in gonads of resting females, of which more than 84% was accounted by docosahexaenoic acid (12.62%). Muscle and liver of resting females presented the highest ω3/ω6 ratios. The Hypocholesterolemic/Hypercholesterolemic index was higher in gonads of both maturation stages (0.97 and 1.05). The results showed that wild Almaco jack at resting stage were a better source of oleic acid and ω3 PUFAs and that liver and gonads present good nutritional by-products.
- Hemiselmis andersenii and Chlorella stigmatophora as new sources of high‐value compounds: a lipidomic approachPublication . Fernandes, Tomásia; Cordeiro, NereidaTo unlock the potential of Chlorella stigmatophora (Trebouxiophyceae, Chlorophyta) and Hemiselmis andersenii (Cryptophyceae, Cryptophyta) as natural reactors for biotechnological exploitation, their lipophilic extracts were characterized using Fourier Transform Infrared spectroscopy with Attenuated Total Reflectance (FTIR-ATR) and Gas Chromatography-Mass Spectrometry (GC-MS) before and after alkaline hydrolysis. The GC-MS analysis enabled the identification of 62 metabolites-namely fatty acids (27), aliphatic alcohols (17), monoglycerides (7), sterols (4), and other compounds (7). After alkaline hydrolysis, monounsaturated fatty acids increased by as much as 87%, suggesting that the esterified compounds were mainly neutral lipids. Hemiselmis andersenii yielded the highest Σω3/Σω6 ratio (7.26), indicating that it is a good source of ω3 fatty acids, in comparison to C. stigmatophora (Σω3/Σω6 = 1.24). Both microalgae presented significant amounts of aliphatic alcohols (6.81-10.95 mg · g dw-1 ), which are recognized by their cholesterol-lowering properties. The multivariate analysis allowed visualization of the chemical divergence among H. andersenii lipophilic extracts before and after alkaline hydrolysis, as well as species-specific differences. Chlorella stigmatophora showed to be a valuable source of essential fatty acids for nutraceuticals, whereas H. andersenii, due to its high chemical diversity, seems to be suitable for different fields of application.
- High-value lipids accumulation by Pavlova pinguis as a response to nitrogen-induced changesPublication . Fernandes, Tomásia; Cordeiro, NereidaThe challenges of exploring the potential of microalgal strains for biotechnological applications include the optimization of their cell growth and chemical composition. To overcome this, it is essential to understand the mechanisms that lead to the accumulation of desired products within microalgal cells. In this study, a gradient of nitrogen as nitrate (NO−3 − N) concentrations was used for the preparation of P. pinguis growth medium. The algal growth dynamics, pigments, nutrient uptake, and detailed lipid composition across treatments were assessed. Increasing the NO− 3 − N level led to higher lipid content (21%), a higher cell uptake rate (0.20 pg NO− 3 − N cell− 1 d− 1 ) and more accumulation of chlorophylls, carotenoids, and high-value lipids. Eicosapentaenoic acid, essential fatty acids, phytol and stigmasterol were the key high-value lipids that were positively influenced by higher NO− 3 − N levels. High NO− 3 − N conditions induced an increase of 54% in total sterol content, while low NO− 3 − N conditions resulted in increased proportions of saturated fatty acids (66% more) and decreased proportions of polyunsaturated fatty acids (14% less). The low NO− 3 − N level also led to higher amounts of monoglyceride (1.60 mg g− 1 ; 64% more). The analysis of P. pinguis lipids before and after hydrolysis provided an insight into the composition of the esterified lipids across treatments. NO− 3 − N supplementation was revealed to be an effective strategy for enhancing P. pinguis lipid composition, for nutraceutical and pharmaceutical industries (high NO− 3 − N level). A greater understanding of the NO− 3 − N uptake and the use efficiency by P. pinguis was reached, showing its potential for further biotechnological applications.
- Exploring Pavlova pinguis chemical diversity: a potentially novel source of high value compoundsPublication . Fernandes, Tomásia; Martel, Antera; Cordeiro, NereidaTo uncover the potential of Pavlova pinguis J.C. Green as a natural source of value added compounds, its lipophilic extracts were studied before and after alkaline hydrolysis using gas chromatography-mass spectrometry (GC-MS). The GC-MS analysis of the lipophilic extracts showed a wide chemical diversity including 72 compounds distributed by fatty acids (29), sterols (14), fatty alcohols (13) and other lipophilic compounds (16). Fatty acids represented the main class of identified compounds presenting myristic, palmitic, palmitoleic and eicosapentaenoic acids as its main components. Through the ∑ω6/∑ω3 ratio (0.25) and sterol composition it was possible to observe that P. pinguis is a valuable source of ω3 fatty acids and stigmasterol (up to 43% of total sterols). After alkaline hydrolysis, fatty acids and fatty alcohols content increased by 32 and 14% respectively, in contrast to, monoglycerides which decreased by 84%. The long chain alcohols content enables the exploitation of this microalga as a source of these bioactive compounds. Smaller amounts of sugars and other compounds were also detected. The present study is a valuable reference to the metabolite characterization of P. pinguis and shows the potential of this microalga for nutraceutical and pharmaceutical industries.
- Microalgae as sustainable biofactories to produce high-value lipids: biodiversity, exploitation, and biotechnological applicationsPublication . Fernandes, Tomásia; Cordeiro, NereidaMicroalgae are often called “sustainable biofactories” due to their dual potential to mitigate atmospheric carbon dioxide and produce a great diversity of high-value compounds. Nevertheless, the successful exploitation of microalgae as biofactories for industrial scale is dependent on choosing the right microalga and optimum growth conditions. Due to the rich biodiversity of microalgae, a screening pipeline should be developed to perform microalgal strain selection exploring their growth, robustness, and metabolite production. Current prospects in microalgal biotechnology are turning their focus to high-value lipids for pharmaceutic, nutraceutic, and cosmetic products. Within microalgal lipid fraction, polyunsaturated fatty acids and carotenoids are broadly recognized for their vital functions in human organisms. Microalgal-derived phytosterols are still an underexploited lipid resource despite presenting promising biological activities, including neuroprotective, anti inflammatory, anti-cancer, neuromodulatory, immunomodulatory, and apoptosis inductive effects. To modulate microalgal biochemical composition, according to the intended field of application, it is important to know the contribution of each cultivation factor, or their combined effects, for the wanted product accumulation. Microalgae have a vital role to play in future low-carbon economy. Since microalgal biodiesel is still costly, it is desirable to explore the potential of oleaginous species for its high-value lipids which present great global market prospects.
- Marine microalgae monosaccharide fluctuations as a stress response to nutrients inputsPublication . Fernandes, Tomásia; Fernandes, Igor; Andrade, Carlos A. P.; Ferreira, Artur; Cordeiro, NereidaThe monosaccharide patterns of the microalgae species Nannochloropsis gaditana, Rhodomonas marina and Isochrysis sp. were assessed, to verify if nutrients availability had an impact on these parameters. Isochrysis sp. and Rhodomonas marina monosaccharides content decreased 13–94% as the nutrients availability increased. The relative abundance of monosaccharides depicted that, at low nutrients availabilities, Rhodomonas marina and Isochrysis sp. had preference for glucans synthesis, accounting for up to 75% of the monosaccharides detected. Linking the monosaccharides trends with the phylogeny and glycolipid data, it was possible to establish which monosaccharides had a structural and/or storage role in the microalgae studied. Thermal analysis revealed that the microalgae submitted to low nutrient input treatments presented a reduced assimilation of the inorganic compounds. Nutrient concentrations affected microalgae monosaccharide patterns, highlighting their taxonomic differences.