Pressurized extraction of unsaturated fatty acids and carotenoids from wet Chlorella vulgaris and Phaeodactylum tricornutum biomass using subcritical liquids

Abstract

The objective of this study was to investigate the extraction of lipids, for example, mono‐ and polyunsaturated fatty acids (PUFA) as well as carotenoids, from wet microalgae biomass using pressurized subcritical extraction solvents, which meet the requirements of food and feed applications. To demonstrate the effect of the solvent and temperature on the lipid yield, we chose two microalgae species, viz. Chlorella vulgaris and Phaeodactylum tricornutum, differing in their biochemical composition fundamentally. In case of P. tricornutum, ethanol showed the highest fatty acid yield of 85.9% w/w. In addition to eicosapentaenoic acid (EPA), the ethanolic extracts contained exceptional amounts of fucoxanthin (up to 26.1 mg/g d. w.), which can be beneficial to protect unsaturated fatty acids from oxidation processes and in terms of human nutrition. For C. vulgaris, a fatty acid yield of 76.5% w/w was achieved from wet biomass using ethyl acetate at 150°C. In general, an increase in the extraction temperature up to 150°C was found to be important in terms of fatty acid yield when extracting wet microalgae biomass. The results suggest that it is possible to efficiently extract both fatty acids and carotenoids from wet microalgae by selecting suitable solvents and thus circumvent energy‐intensive drying of the biomass.

ERK1/2 Pathway Is Involved in the Enhancement of Fatty Acids from Phaeodactylum tricornutum Extract (PTE) on Hair Follicle Cell Proliferation

“…Phaeodactylum tricornutum ( P. tricornutum ), an interesting natural material, is a common type of marine diatoms with three different morphotypes, of which the genomes have been fully sequenced [ 1 ]. P. tricornutum constituents with multiple components such as proteins, carotenoids like fucoxanthin, polyphenols like (epi-)catechin, vitamins, minerals, and several kinds of lipophilic materials of polyunsaturated fatty acids (PUFAs), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which might mediate physiological values [ 2 – 6 ].…”

Sequential extraction of lutein and β‐carotene from wet microalgal biomass

“…Alternatively, fresh wet microalgal biomass could be directly stored in the freezer and then defrosted before the extraction test. 13,26,36,37 Some of the studies that have followed this approach have not evaluated the influence of freeze storage on the biochemical composition of microalgae. Yet, this analysis is fundamental to assess whether the performed extraction experiments can be representative of an industrial-scale production process, where extraction is performed immediately after microalgal harvesting, without storing.…”

“…Yet, this analysis is fundamental to assess whether the performed extraction experiments can be representative of an industrial-scale production process, where extraction is performed immediately after microalgal harvesting, without storing. 26,36 Only in a previous study, lutein extraction was studied by comparing the results obtained with wet fresh microalgal biomass and wet frozen biomass (at -20°C and -86°C). 13 No difference was found, suggesting that freezing at -20°C is enough to have an effective method to store microalgal biomass containing lutein.…”

“…Although different studies have been published about lutein extraction, from both dried and wet microalgal biomass, by using high-pressure and supercritical solvents, 26,36,43,53 these were not included in this comparison because the high temperatures (40-150°C) and the high pressures (70-400 bar) require substantially different process design during the extraction phase, for which the assessment of the energy consumption goes beyond the scope of the present study.…”

Experimental and Model-Based Analysis to Optimize Microalgal Biomass Productivity in a Pilot-Scale Tubular Photobioreactor

“…In comparison to plants, microalgae are in general structurally less complex and show higher area productivities (Derwenskus et al, 2018). Their gross biochemical composition can be influenced without genetic modifications (Gu et al, 2012;Draaisma et al, 2013).…”