Optimization of cell wall disruption and lipid extraction methods by combining different solvents from wet Chlorella vulgaris

Abstract

AbstractOver the past few decades, microalgae have emerged as a promising option for making lipid‐based bioactive compounds. The purpose of this study was to extract lipids from Chlorella vulgaris. In this study, different cell wall disruption methods such as microwave, liquid nitrogen, ultrasound (US), and bead mill were compared. We selected and optimized two systems based on their efficacy in disrupting cell walls—US and beads mill. Based on the dry weight of C. vulgaris biomass, the maximum lipid extraction by the US was 17.1% and by bead mill was 15.2%. Following cell wall disruption of C. vulgaris, chloroform–methanol (2:1) solvent combination achieved high lipid extraction. However, the hexane–ethanol (1:1) solvent combination was chosen because of its lower toxicity. Specifically, the effect of the solvent‐to‐biomass ratio, the temperature, and the extraction time was investigated. The results indicated that the chloroform–methanol solvent combination yielded optimal results at 8 ml/g solvents to biomass, 45°C, and 60 min and that the hexane–ethanol combination yielded optimal results at 6 ml/g, 35°C, and 73 min, respectively. The highest amount of lipids was obtained from C. vulgaris with 87.6% moisture content. As a cell wall disruption method, the US obtained 20.4% and 16.4% with a combination of chloroform–methanol solvents and hexane–ethanol, respectively. Additionally, bead milling resulted in the highest extraction yield of 17.6% for chloroform–methanol and 13.9% for hexane–ethanol. Based on the results of cell wall disruption, the US method is the most efficient cell wall disruption method in terms of lipid extraction efficiency.