Browsing by Author "Saraiva, J.A."
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- Effect of airflow conditions on growth and simultaneously DHA and squalene production by Aurantiochytrium sp. PRA-276Publication . Paulo, M.C.; Coutinho, J.; Saraiva, J.A.; Pinto, C.A.; Amaral, R.; Melo, M.M.R.; Pinheiro, J.; Lemos, M.F.L.; Cardoso, C.; Sapatinha, M.; Bandarra, N.M.There has been a growing trend worldwide in the use of squalene and docosahexaenoic acid (DHA), due in part to their recognized health benefits and their range of applications. However, the growth of the industry exploiting these resources has been extremely limited by the scarcity and limitations of raw material, leading to the need to develop more sustainable sources of production. Aurantiochytrium sp. PRA-276, with the ability to produce high concentrations of DHA and squalene, is a promising candidate for the commercial production of these biomolecules. The aim of this study was to determine the cumulative effect of airflow levels and stirring speed of Aurantiochytrium sp. PRA-276 biomass during DHA and squalene production. Different airflow levels (3, 6 and 9 L min-1) and two stirring speeds (150 and 300 rpm) were investigated. The highest biomass production was achieved after 96 hours with 300 rpm stirring speeds and airflow level of 9 L min-1. The maximum total lipids content reached 61.4% of the dried biomass, and the optimal parameters for DHA and squalene production were stirring speed 150 rpm and airflow level 3 L min-1. The maximum yield of DHA production was 4.3 g L-1 at 96 h of fermentation. The highest yield of squalene production was 762.5 mg L-1 at 48 hours of growth. The results show that Aurantiochytrium sp. PRA-276 is a promising resource for microbial DHA and squalene production due to the high yield of DHA and squalene that it generates. Moreover, the capacity for large-scale fermentation of this organism could be useful for the synthesis of biomass related products with high added value.
- Supercritical CO2 extraction of Aurantiochytrium sp. biomass for the enhanced recovery of omega-3 fatty acids and phenolic compoundsPublication . Melo, M.M.R. de; Sapatinha, M.; Pinheiro, J.; Lemos, M.F.L.; Bandarra, N.M.; Batista, I.; Paulo, M.C.; Coutinho, J.; Saraiva, J.A.; Portugal, I; Silva, C.M.The microalgae Aurantiochytrium sp. is a strong alternative source of ω-3 fatty acids, including ocosahexaenoic acid (DHA). This work encompasses the optimization of SFE conditions to maximize the total extraction yield (ηTotal), DHA content (CDHA), total phenolics content (TPC), and antioxidant capacity (AOC) of the extracts produced from Aurantiochytrium sp. biomass. A full factorial experimental plan was performed, comprising three factors (pressure, temperature, and flow rate) and two levels (200−300 bar, 40−80 °C, and 6–12 gmin−1, respectively). The maximum and minimum experimental results were ηTotal = 2.1 and 13.4 wt.%, CDHA= 27.3 and 39.3 wt.%, TPC =1.19 and 2.24 mgGAE g−extract 1 , and AOC = 0.3 and 1.4 mg g− TEAC extract 1. Under the studied experimental conditions, increasing pressure up to 300 bar is the optimum to rise both ηTotal and CDHA. Temperature increase from 40 to 80 °C leads to opposing effects: it favors the concentration of phenolics in the supercritical extracts at the expenses of decreasing DHA content and total yield. Surface models were adjusted to ηTotal, CDHA and TPC data, and the goodness of the fits ranged from coefficients of determination of 0.752-0.711 (TPC) to 0.997-0.994 (CDHA). Under optimized conditions, supercritical extracts exhibited a DHA content more than 3.5-fold richer than fish oil, and 7.9-fold richer than the best alternative microalgae species (Pavlova lutheri) found in the literature.