resumo
Microalgae are emerging as sustainable sources of a wide range of high-value compounds. However, the knowledge about microalgae polar lipids is still limited, despite their interest due to their chemical diversity and bioactivity. This study shows, for the first time, the polar lipidome of the haptophyte microalga Chrysotila pseudoroscoffensis unveiled by using hydrophilic interaction liquid chromatography-high resolution mass spectrometry (HILIC-HRMS and MS/MS) and gas chromatography-mass spectrometry (GC-MS). Freeze-dried C. pseudoroscoffensis biomass has a lipid content of 6.4 %, containing higher amounts of ash (45.5 %), proteins (11.6 %), and sugars (11.0 %). Uronic acids (53.8 mol%) are the sugars present in higher content, followed by glucose (13.7 mol%) and galactose (12.7 mol%). The polar lipid species identified by HILIC-MS/MS included betaine lipids, glycolipids, and phospholipids, some of them with recognised bioactive properties. Among the lipid classes found from C. pseudoroscoffensis, some are less reported in algae: betaine lipids diacylglycerylcarboxyhydroxymethylcholine (DGCC) and monoacylglycerylcarboxyhydroxymethylcholine (MGCC) (characteristic of haptophyte microalgae); acid glycolipid class glucuronosyldiacylglycerol (GlcADG) (mainly reported in plants with protective effects in phosphate-deprivation conditions); and phospholipid classes monomethylphosphatidylethanolamine (MMPE) and lysomonomethylphosphatidylethanolamine (MMLPE). As estimated by colorimetric assays, glycolipids and phospholipids accounted for 64 and 3 % of the total lipid extracts, respectively. Fatty acid profiling by GC-MS showed that total esterified fatty acids accounted for about 32 % of the total lipid extracts, of which 23 % were omega-3 polyunsaturated fatty acids (PUFA). Four lipid extract concentrations (12.5, 62.5, 125 and 250 mu g mL-1 in ethanol) were tested and displayed antioxidant capacity toward 2,2 & PRIME;-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. A dose-dependent behaviour was observed with IC50 of 111.9 mu g mL(-1) for ABTS and IC35 of 234.8 mu g mL(-1) for DPPH assay. In conclusion, the lipid extracts of C. pseudoroscoffensis may be a source of high-value lipids for the development of novel microalgae-based products, namely nutraceuticals and cosmeceuticals.
palavras-chave
MARINE MICROALGAE; BETAINE LIPIDS; FATTY-ACIDS; GREEN-ALGA; ACCUMULATION; ALKENONES; INHIBIT; INFECTION; NITROGEN; DISEASE
categoria
Biotechnology & Applied Microbiology
autores
Moreira, ASP; Goncalves, J; Conde, TA; Couto, D; Melo, T; Maia, IB; Pereira, H; Silva, J; Domingues, MR; Nunes, C
nossos autores
Ana Sofia Pereira Moreira
Investigador Júnior
Cláudia Nunes
Investigador Auxiliaragradecimentos
The authors acknowledge the FCT/MCT (Portugal) for the financial support of the project Coccolitho4BioMat (POCI-01-0145-FEDER031032), to research units CICECO (UIDB/50011/2020 + UIDP/50011/2020), LAQV-REQUIMTE (UIDB/50006/2020), and CESAM (UIDP/50017/2020 + UIDB/50017/2020 + LA/P/0094/2020), and to RNEM (LISBOA-01-0145-FEDER-402-022125) and CCMAR (UIDB/04326/2020), through national funds and, where applicable, co-financed by the FEDER, within the PT2020 Partnership Agreement and Compete 2020. This work was also funded by national funds (OE), through FCT Fundacao para a Ciencia e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. Ana Moreira thanks the contract in the scope of the project Coccolitho4BioMat. Tania Melo thanks the Junior Researcher contract in the scope of the Individual Call to Scientific Employment Stimulus 2020 (CEECIND/01578/2020). Daniela Couto and Tiago Conde are grateful to FCT for the PhD grants (SFRH/BD/138992/2018; 2020.05678.BD).