Extraction of Carotenoids and Fatty Acids from Microalgae Using Supercritical Technology

Abstract

<p class="MsoNormal"> <span lang="EN-GB">The work described here is based on a comparative study of carotenoids and fatty acids extracted from <i>Synechococcus </i>sp. with (1) pure supercritical CO<sub>2</sub>, (2) CO<sub>2</sub> with 5% (v/v) ethanol as cosolvent and (3) ultrasound-assisted extraction using <i>N</i>,</span><span lang="EN-GB"> </span><i><span lang="EN-GB">N</span></i><span lang="EN-GB">-dimethylformamide (DMF). The effects of extraction conditions on supercritical CO<sub>2</sub> extraction with and within cosolvent were analyzed at different temperatures (40℃, 50<span style="white-space:normal;"><span style="white-space:normal;">℃</span></span> and 60<span style="white-space:normal;"><span style="white-space:normal;">℃</span></span>) and pressures (200, 300 and 400 bars). SFE with CO<sub>2 </sub>proved to be the most selective method for the extraction of <i>β</i>-carotene, but under these conditions the contents of zeaxanthin and fatty acids were only comparable to or lower than those obtained with techniques that use SFE cosolvent. The SFE technique with CO<sub>2</sub> and ethanol simultaneously extracted <i>β</i>-carotene and zeaxanthin and not only increased the concentrations of fatty acids obtained, but also helped to remove fatty acids (palmitoleic and lino</span><span lang="EN-GB">lenic acid) that were not obtained with pure CO<sub>2</sub>. </span><span lang="EN-US">Comparison of the supercritical technology with the ultrasound-as</span><span lang="EN-US">sisted extraction (UAE) shows that the former technique is the most appropriate due to the fact that ethanol is generally regarded as a safe solvent in comparison to DMF.</span> </p&gt

Innovative Alternative Technologies to Extract Carotenoids from Microalgae and Seaweeds

“…While studying the effects of pressure (200–600 bar ) and temperature (32–60 °C), the maximum yield of lutein was recovered at intermediate pressures, except for the extraction at 46 °C where the maximum yield was obtained at 600 bar [112]. Furthermore, a number of studies have shown similar effects of pressure and temperature on the recovery of several carotenoids [107,108,110,111,114,115,116,117,118,119,120,121]. …”

“…Several researchers have used co-solvents such as ethanol [26,108,109,111,113,114,118,120,121,122,123,124,125,126,127], acetone [113], vegetable oil [26,106,128] as polarity modifiers for the efficient recovery of carotenoids such as β-carotene [113,118], astaxanthin [106,109,114,120,121,122,125,129], lutein [111,113] and zeaxanthin [118]. Since supercritical CO 2 is non-polar, addition of a small amount of co-solvent increases the ability of supercritical CO 2 to dissolve relatively polar carotenoids.…”

“…Although the use of co-solvents improves the extraction yield, in some cases, the presence of co-solvents can decrease the selectivity of the extraction [113,118]. Cardoso et al [118] showed that although the obtained yield of β-carotene increased on using CO 2 and 5% ethanol as a co-solvent, under these conditions zeaxanthin was co-extracted.…”

“…Cardoso et al [118] showed that although the obtained yield of β-carotene increased on using CO 2 and 5% ethanol as a co-solvent, under these conditions zeaxanthin was co-extracted. In any case, the selectivity was also dependent on SFE parameters such as pressure and temperature [118], including extraction time [113]. Thus, the use of a co-solvent might tend to compromise product purity and should be considered.…”

Comparative study of the extraction methods for recovery of carotenoids from algae: extraction kinetics and effect of different extraction parameters

“…Several methods have been applied for separation of carotenoids, for example conventional extraction, extraction under supercritical CO 2 , or using high pressure, and saponification of algae by alkali followed by extraction . Alternatively a combined process of alkali catalyzed transesterification and hydrolysis of lutein ester has been proposed for production of biodiesel and lutein, respectively .…”