Enhanced and Selective Lipid Extraction from the Microalga P. tricornutum by Dimethyl Carbonate and Supercritical CO₂ Using Deep Eutectic Solvents and Microwaves as Pretreatment

Abstract

Microalgae are a promising alternative source of several bioactive compounds useful for human applications. However, lipids are traditionally extracted with toxic organic solvents (e.g. mixture of chloroform and methanol or hexane). In this work, we developed a new lipid extraction protocol to obtain a fatty acids rich extract from the diatom Phaeodactylum tricornutum. Deep Eutectic Solvents (DES) and microwaves (MW) were investigated as pre-treatments for environmentally friendly solvent extractions using dimethyl carbonate (DMC) and supercritical CO2 (scCO2). Pre-treatments with various DES formed by choline chloride (ChCl) and different hydrogen bond donors (oxalic acid, levulinic acid, urea, ethylene glycol and sorbitol) were tested in combination with DMC extraction. DES formed by ChCl and carboxylic acids gave best results, increasing both selectivity and total fatty acids (TFA) extraction yield of DMC (respectively by 16% and 80%). DES combined with MW heating followed by DMC extraction allows to reach comparable TFA yield and fatty acid profile to traditional Bligh & Dyer extraction method and much better selectivity (88% vs. 35%). This pre-treatment was also demonstrated to improve significantly extraction efficiency of scCO2, increasing by 20 times TFA yield and providing highly purified triglycerides extracts.

Co-production of biodiesel and bioethanol using psychrophilic microalga Chlamydomonas sp. KNM0029C isolated from Arctic sea ice

“…were recovered by the B&D-based method, but not the Lewis's method, that recovered much less. Tommasi et al [28] reported a similar result, where the B&D method recovered most of the fatty acids from Phaeodactylum tricornutum. In contrast, Cavonius et al [29] reported that the Lewis's method showed higher fatty acid recovery from Nannochloropsis oculata and Isochrysis galbana, than B&D's method.…”

Optimization of Glycolipid Synthesis in Hydrophilic Deep Eutectic Solvents

“…Later, EtAc started replacing chloroform as an extraction solvent (Koster et al, 1994;Siebenhaller et al, 2016). More recently, to extract polar and nonpolar lipids from microalgae, DMC is used as an alternative to traditional chloroform extraction (Lee et al, 2013;Tommasi et al, 2017). On this account, these three solvents have been chosen to be investigated.…”

Natural Deep Eutectic Solvent-Assisted Pectin Extraction from Pomelo Peel Using Sonoreactor: Experimental Optimization Approach

“…All of the NADESs were prepared based on the molar ratio of choline chloride and the hydrogen bond donor (HBD) and all ratios were presented in Section 3.1. The appropriate ratio for the preparation was taken from the literature [14,15]. Choline chloride (ChCl) and an HBD (of choice) were mixed at a specific molar ratio, and heated and stirred at a speed of 350 rpm and a temperature at 80 • C (Thermo Scientific TM , Waltham, MA, USA) for 2 h until a homogeneous and stable mixture with no visible precipitate was obtained.…”