Enhancement of pigment extraction from B. braunii pretreated using CO 2 rapid depressurization

Abstract

Extraction of compounds from microalgae requires cell disruption as a pretreatment to increase extraction yield. Botryococcus braunii is a microalga with a significant content of carotenoids and other antioxidant compounds, such as chlorophylls. Cell disruption of B. braunii using CO2 rapid depressurization was studied as a pretreatment for the extraction of carotenoid and chlorophyll pigments. We studied the effect of temperature (21–49 °C) and pressure (6–13 MPa) during static compression on pigment recovery with supercritical CO2 at 40 °C, 30 MPa and solvent flow of 4.7 L NPT/min. Within the experimental region, the extraction yield of carotenoids and chlorophylls increased by 2.4- and 2.2-fold respectively. Static compression conditions of high pressure and low temperature increased the extraction of carotenoids and especially chlorophylls. We selected 21 °C and 13 MPa as the cell disruption condition, which produced 1.91 g/kg d.s. of carotenoids and 14.03 mg/kg d.s. of chlorophylls. Pretreated microalga gave a 10-fold higher chlorophyll extraction yield compared to the untreated sample. While for carotenoids and tocopherols were 1.25 and 1.14-fold higher, respectively. Additionally, antioxidant activity of pretreated microalga (33.22 mmol TE/kg oil) was significantly higher than the value for the untreated samples (29.11 mmol TE/kg oil) (p ≤ 0.05). Confocal microscopy images showed morphological differences between micro-colonies with and without disruption treatment, suggesting that partial cell disruption by rapid depressurization improved the extraction of microalga compounds.

Effect of Organic Solvents on Microalgae Growth, Metabolism and Industrial Bioproduct Extraction: A Review

“…Supercritical liquids have densities similar to liquids, but decreased viscosities and enhanced diffusivities like gasses, thereby possessing higher power to penetrate into biomass and extract products when compared to conventional liquids [ 165 ]. For carotenoid production, the commonly used supercritical fluid is CO 2 [ 166 ], together with the addition of organic solvents [ 167 , 168 ], to enhance the extraction.…”

Green Chemistry Extractions of Carotenoids from Daucus carota L.—Supercritical Carbon Dioxide and Enzyme-Assisted Methods

“…SC-CO 2 is a non-polar solvent that can replace one of the most commonly used non-polar solvents such as hexane. The compound’s solubility in SC-CO 2 is dependent on the compound’s polarity, molecular weight, and structure [76]. Components with lower molecular weight and lower polarity could be extracted easily at low pressures with SC-CO 2 because they could perfectly match the solvent’s polarity at this pressure.…”

Steam Explosion and Vibrating Membrane Filtration to Improve the Processing Cost of Microalgae Cell Disruption and Fractionation

“…To achieve a positive economic balance, several matters should be taken into account such as CO 2 capture [6,7], water quality improvement [8,9], procurement of commodities [10,11], and high-added value products [12,13].…”

“…The process unit operations needed in order to proceed to microalgae biorefining depend very much on the strain and products to be sought (i.e., commodity or high-added value products), but a typical sequence is: Culture in open ponds or photobioreactors [14,15], dewatering [16][17][18][19][20][21], cell disruption [22][23][24][25][26][27], and fractionation [13,20,28].…”