| Abstract [eng] |
Phaeodactylum tricornutum, the only species in the genus Phaeodactylum, belongs to a significant group of microalgae called diatoms. P. tricornutum is considered a promising feedstock of high-value products. Mainly, due to its ability to synthesize polyunsaturated fatty acids, like eicosapentaenoic acid, and carotenoids, especially fucoxanthin – a valuable pigment with multiple biological activities. This work aimed to develop multi-step P. tricornutum processing schemes for isolation of high-added value fractions using conventional and high-pressure extraction techniques. Various standard methods achieved the determination of chemical composition. Conventional and high-pressure extraction techniques like solid-liquid extraction (SLE), supercritical fluid extraction (SFE), and pressurized liquid extraction (PLE) were applied using various solvents in order to obtain extracts of various polarity. The high-pressure extraction techniques, SFE and PLE, were optimized using response surface methodology (RSM) in order to maximize total yield, carotenoid, and fucoxanthin content. In vitro antioxidant capacity of initial material, as well as all extracts were determined using the total phenolic content (by the Folin-Ciocalteu method), DPPH• and ABTS•+ assays. The activity of solid residues was tested with the same in vitro antioxidant capacity assays following the QUENCHER approach. The qualitative determination of pigments and quantitative determination of fucoxanthin content was performed using HPLC-DAD. The fatty acid profile was determined using GC-FID. Moreover, for all extracts, the antimicrobial activity was using the disc diffusion assay, determining the minimal inhibitory concentration for the active ones. This work demonstrates the feasibility of high-pressure techniques for the isolation of high-added value products from this rather underutilized feedstock. |
