Biofuel production from wet microalgae biomass: Comparison of physicochemical properties and extraction performance. (1st December 2020)

• Record Type: Journal Article
• Authors: Xia, Ao; Sun, Chihe; Fu, Qian; Liao, Qiang; Huang, Yun; Zhu, Xun; Li, Qing
• Is Part Of: Energy. Volume 212(2020)
• Publication Date: 2020-12-01
• Subjects: Algae -- Cell disruption -- Biofuel -- Formic acid assisted extraction -- Hydrothermal hydrolysis; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Energy consumption -- Periodicals; 333.7905
• DOI: 10.1016/j.energy.2020.118581
• Languages: English
• ISSNs: 0360-5442

Abstract

Abstract: A one-step process that integrates cell disruption with lipid extraction from wet microalgae was proposed by using n-hexane/formic acid. The scanning electron microscopy showed that raw microalgae cells were completely disrupted. The derivative thermogravimetric analysis indicated that formic acid could lead to a fast-thermal decomposition of microalgae residues at the temperatures ranged from 175 to 280 °C. The Fourier transform infrared spectroscopy revealed that the intensities of CO vibrations increased with an increase of the carbonyl compounds. When microalgae were treated with this mixed solvent at an n-hexane/formic acid ratio of 9:2 (v/v) and an addition dosage of 80 mL/g wet microalgae at 80 °C for 2 h, the optimal crude lipid yield was 256.3 mg/g dry weight. A high fatty acid methyl ester (FAME) content of 83.6% was achieved, dominated by palmitic acid, palmitoleic acid, oleic acid, and linoleic acid. Compared with the conventional methods including n-hexane, ethanol, n-hexane/methanol, and chloroform/methanol without pre-treatment, the crude lipid yields increased by 15%–402%. Compared with the chloroform/methanol extraction supplemented by ultrasound, microwave, hydrothermal, and dilute nitric acid pre-treatments, the achieved FAME contents increased by 79%–99%. Additionally, the energy yield from n-hexane/formic acid extraction reached up to 8.55 kJ/g volatile solid. Graphical abstract: Image 1 Highlights: N-hexane/formic acid was used to extract lipids from wet microalgae. Cell disruption and lipid extraction could be simultaneously achieved. Physicochemical properties of solid residues were comparatively assessed. High fatty acid methyl ester content of 83.6% was achieved by n-hexane/formic acid. Maximum energy yield from n-hexane/formic acid was 8.55 kJ/g volatile solid.