Supercritical CO2 extraction of Aurantiochytrium sp. biomass for the enhanced recovery of omega-3 fatty acids and phenolic compounds

abstract

The microalgae Aurantiochytrium sp. is a strong alternative source of omega-3 fatty acids, including docosahexaenoic acid (DHA). This work encompasses the optimization of SFE conditions to maximize the total extraction yield eta(Total)), DHA content (C-DHA), 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 degrees C, and 6-12 g min(-1), respectively). The maximum and minimum experimental results were eta(Total) = 2.1 and 13.4 wt%, C-DHA= 27.3 and 39.3 wt. %, TPC = 1.19 and 2.24 mg(GAE )g(extract)(-)1 and AOC = 0.3 and 1.4 mg(TEAC )g(extract)(-1). Under the studied experimental conditions, increasing pressure up to 300 bar is the optimum to rise both eta(Total) and C-DHA. Temperature increase from 40 to 80 degrees 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 eta(Total), C-DHA 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 (C-DHA). 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.

keywords

CARBON-DIOXIDE EXTRACTION; EUCALYPTUS-GLOBULUS BARK; FLUID EXTRACTION; DOCOSAHEXAENOIC ACID; OPTIMIZATION; MICROALGAE; CAROTENOIDS; OIL; METHODOLOGY; LYCOPENE

subject category

Chemistry; Engineering

authors

de Melo, MMR; Sapatinha, M; Pinheiro, J; Lemos, MFL; Bandarra, NM; Batista, I; Paulo, MC; Coutinho, J; Saraiva, JA; Portugal, I; Silva, CM

Groups

G4 - Renewable Materials and Circular Economy

Projects

Valorização dos subprodutos do processo biotecnológico de produção de esqualeno e DHA pela microalga Aurantiochytrium sp. (Algavalue)

AgroForWealth - Biorefinação de sub-Produtos agrícolas e florestais: uma estratégia de valorização de recursos para o bem estar social e a sustentabilidade (AGROFORWEALTH)

acknowledgements

This work was funded by the project Valorizacao dos subprodutos do processo biotecnologico de producao de esqualeno e DHA pela microalga Aurantiochytrium sp. (AlgaValue) (ref. 17680), and within the scope of the project CICECO Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, and strategic program of MARE (MARE UID/MAR/04292/2013), financed by national funds through the FCT/MCTES. Authors also thank the funding from Project AgroForWealth (CENTRO-01-0145-FEDER-000001), funded by Centro2020, through FEDER and PT2020 and University of Aveiro and FCT/MCT for the financial support for the QOPNA research Unit (FCT UID/QUI/00062/2019) through national founds and, where applicable, co-financed by the FEDER, within the PT2020 Partnership Agreement. The project was also partially funded by the Integrated Programme of SR&TD SmartBioR (reference Centro-01-0145-FEDER-000018) cofunded by Centro 2020 program, Portugal2020, European Union, through the European Regional Development Fund.