Supercritical fluid extraction of carotenoids from red microalgal biomass of Chromochloris zofingiensis

Abstract

Microalgae serve as a potent source of bioactive compounds, particularly astaxanthin, a xanthophyll with antioxidant capabilities significantly exceeding those of vitamin E and other carotenoids. While traditional pigment extraction relies on environmentally harmful organic solvents, this study successfully utilized supercritical fluid extraction (SFE) with CO₂ a green alternative, to isolate carotenoids from Chromochloris zofingiensis. By optimizing parameters via Central Composite Design (CCD) and implementing pretreatments such as grinding and lyophilization, researchers attained a carotenoid yield of 210 mg/100 g dry biomass. High Performance Liquid chromatography (HPLC) analysis confirmed a high concentration of astaxanthin within the extract. The findings demonstrate that while operating pressure (350 MPa) is the primary determinant of extraction efficiency, maximal yields are achieved when pressures exceeding 350 MPa are applied in conjunction with temperatures below 55 °C. This synergy suggests that maintaining a lower thermal profile at ultra-high pressures optimizes the solubility and recovery of target compounds.