Process Optimization of Microwave-Assisted Extraction of Chlorophyll, Carotenoid and Phenolic Compounds from Chlorella vulgaris and Comparison with Conventional and Supercritical Fluid Extraction

Abstract

The production of bioactive products from microalgae biomass with efficient and environmentally friendly technologies is a field of great research interest. The present work focuses on the recovery of high-added value bioactive components from Chlorella vulgaris through microwave-assisted extraction (MAE) with aq. ethanol 90% v/v. The effect of extraction temperature (40–60 °C), duration (5–25 min), solvent-to-biomass ratio (20–90 mLsolv/gbiom), and microwave power (300–800 watts) was investigated regarding the extraction yield, extract’s chlorophyll, carotenoid and phenolic content, and antioxidant activity. MAE optimization at 60 °C, 300 watts, 14 min, and 22 mLsolv/gbiom led to 11.14% w/w yield, 63.36 mg/gextr total chlorophylls, 7.06 mg/gextr selected carotenoids of astaxanthin, lutein and β-carotene, 24.88 mg/gextr total carotenoids, 9.34 mgGA/gextr total phenolics, and 40.49 mgextr/mgDPPH IC50 (antioxidant activity indicator). Moreover, the conventional solid-liquid extraction (SLE) with aq. ethanol 90% v/v, the supercritical fluid extraction (SFE) with CO2, as well as SFE with cosolvent addition (10% w/w ethanol), were also performed for comparison purposes. The results revealed that SLE presented the highest yield. However, the non-conventional methods of MAE and SFE led to extracts of competitive or even better quality under significantly shorter extraction duration.

Evaluation of Polyphenolic Profile and Antioxidant Activity of Sea Buckthorn (Elaeagnus rhamnoides (L.) A. Nelson) Leaf and Berry Extracts Obtained via Optimized Microwave-Assisted and Accelerated Solvent Extraction

“…On the other hand, the TPC content in leaf extracts obtained by MAE and ASE was almost identical to those obtained after 30 min of CE (10,652.7 mg/100 g), demonstrating the advantages of MAE and ASE, namely the decrease in extraction time and solvent consumption. A similar trend was observed by Ince et al [61] for aerial parts of dry nettle extracts, by Elez Garofulić et al [18] for Pistacia lentiscus L. fruit and leaves extracts, by Georgiopoulou et al [62] for Chlorella vulgaris extracts, and by Alhallaf et al [63] for nonotus obliquus (chaga) sclerotia extracts.…”

Sustainable Green Extraction of Carotenoid Pigments: Innovative Technologies and Bio-Based Solvents

“…The effects of the SFE (10% (w/w) of ethanol, 250 bars, 60 • C, flow rate of 40 g/min, and total solvent consumption of 100 kg CO 2 / kg biomass) on the extraction of carotenoids from C. vulgaris were also evaluated. According to this study, the use of this method resulted in approximately 1.8-and 1.4-fold increases in the total amounts of extracted carotenoids when compared to that of a conventional solid-liquid extraction (aqueous ethanol 90% (v/v), 24 h) and a MAE method (60 • C, 300 W, 14 min, and 22 mL/g (solvent/biomass)), respectively [38]. The SFE of carotenoids has been also optimized in several matrices, such as pink grapefruit (325 bar, 64 • C, and 143 min, rice bran oil as co-solvent, CO 2 and rice bran oil flow rate set at 35 g/min, and 3% of CO 2 (w/w)) or carrot peel (349 bar, 80 min, 59 • C, 15.5% ethanol as co-solvent, CO 2 flow rate of 15 g/min) [39,40].…”

Approach of Supercritical Carbon Dioxide for the Extraction of Kleeb Bua Daeng Formula

“…The same group has also used a Face-Centered Central Composite Design (FC-CCD) with RSM to optimize the process of MAE to obtain chlorophyll, carotenoid, and phenolic compounds from a microalga, Chlorella vulgaris, and compared the results with those obtained from SLE and SFE [27]. They have found that, under the optimized conditions, the percentage extraction yield obtained by SLE was higher than that obtained by MAE, which was, in turn, higher than that obtained by SFE.…”