Abstract Detail



Phycology

Maglie, Michele [1], Marzullo, Angela [2], Maietti, Annalisa [3], Baldisserotto , Costanza [4], Pancaldi, Simonetta [4].

Semi-continuous autotrophic and mixotrophic cultivation of Tisochrysis lutea: antioxidant activity evaluation of methanolic extracts by DPPH assay.

The great biodiversity of microalgae and their different biochemical composition make them attractive as commercial sources of a wide range of biomolecules (vitamins, amino acids, PUFA, pigments). These molecules can modulate many biological activities and have antioxidant, anti-inflammatory, antitumor, antibacterial, antiviral and detox properties (1;2). In this study Tisochrysis lutea grew in semi-continuous autotrophic and mixotrophic cultivation. Antioxidant activity of methanolic microalgae extract was evaluated by DPPH assay. Axenic cultures grown and maintained in liquid f/2 medium in a growth chamber (25 ± 1 °C; 60 μmol m−2 s−1 white LED; 16:8 h of light-darkness photoperiod), without shaking and external CO2 supply. In mixotrophic culture glycerol was added with concentration of 2.5 g L-1. Every seven days, both autotrophic and mixotrophic cultures were brought again to the initial concentration of 2 x 106 cells mL−1. Autotrophic and mixotrophic cultures showed differences in growth kinetic, maximum quantum yield of PSII (FV/FM ratio) and morphological characteristics. Higher growth and increased lipid globules accumulation have been shown in mixotrophic cultures compared to autotrophic ones. Autotrophic cultures showed constant values of FV/FM ratio (> 0.6), instead mixotrophic cultures showed fluctuating values correlated to the different growth phases. Antioxidant activity was expressed as IC50 values and methanolic extracts concentration was expressed referring to the total carotenoids. Extracts from mixotrophic culture had a higher antioxidant capacity than that obtained from autotrophic ones. In order to highlight quality differences in the pigments in autotrophic and mixotrophic cultures, the fourth derivative of the absorption spectrum of each sample was extrapolated. No substantial differences were found. To explain the major antioxidant activity of mixotrophic cultures, a contribution to DPPH scavenging by the lipids present in the extract has been hypothesized. Therefore, lipids extraction and analysis by gas chromatography were performed on samples of both autotrophic and mixotrophic T. lutea cultures. Autotrophic samples had more saturated fatty acids than those mixotrophic. On the contrary, mixotrophic microalgae showed higher concentration of unsaturated fatty acids and this could partially explain the results obtained regarding the antioxidant activity of the extracts. Further study will be necessary to characterize the methanolic extract and study the antioxidant activity of various T. lutea extracts evaluating the use of different solvents.
(1) Matos A.P. (2017) J Am Oil Chem Soc 94:1333-1350 (2) Barkia I. et al. (2019) Mar. Drugs, 17 (5), 304


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1 - University of Ferrara , Department of Life Sciences and Biotechnology, Via L. Borsari, 46, Ferrara, FE, 44121, Italy
2 - University of Ferrara, Via L. Borsari, 46, Ferrara, FE, 44121, Italia
3 - University of Ferrara, Department of Chemical and Pharmaceutical Sciences, Via Fossato di Mortara, 17, Ferrara, FE, 44121, Italia
4 - University of Ferrara, Department of Life Sciences and Biotechnology, Via L. Borsari, 46, Ferrara, FE, 44121, Italia

Keywords:
Microalgae 
Tisochrysis lutea
Mixotrophy
Semi-continuous
DPPH assay.

Presentation Type: Poster Time and date to be determined
Number: PPY001
Abstract ID:323
Candidate for Awards:None


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