Extraction, optimization, and characterization of oil from green microalgae Chlorophyta species

ABSTRACT

Optimization of oil separation from algae biomass via a Soxhlet extraction method was studied. The extracted oil was characterized for its functional groups and chemical composition using Fourier transform infrared (FTIR) spectroscopy and gas chromatography-mass spectrometry (GC-MS), respectively. In addition, the basic physicochemical properties of the algal oil were evaluated in order to ascertain its quality. Central composite design was used for optimization of Soxhlet extraction process. Predicted values of oil extraction yield were found to be in good agreement with the experimental values obtained$\left({\mathrm{R}}^2=0.9675\mathrm{a}\mathrm{n}\mathrm{d}\mathrm{A}\mathrm{d}\mathrm{j}-{\mathrm{R}}^2=0.9396\right)$. Optimization results showed that maximum oil yield of 18.29 $\pm$ 0.4 wt.% was achieved at the optimum conditions of 61.31 °C extraction temperature, 2.54 h extraction time, and 0.59 mm particle size. The FTIR analysis revealed the presence of alkane (C–H), esters (C=O), carboxylic acid (C–O, C=O, and O–H), and unsaturated (=C–H) groups on the extracted oil, while the result from the GC-MS analysis confirmed the presence of various fatty acids. The physicochemical properties of the extracted algal oil conformed to American Society for Testing and Method (ASTM) standard and the values reported in the literature.

KEYWORDS:

• Optimization
• extraction
• characterization
• Chlorophyta
• microalgae

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Adeyinka S. Yusuff

Adeyinka S. Yusuff obtained his PhD from the Federal University of Technology, Minna, Nigeria in 2017. He is a senior lecturer at the Department of Chemical & Petroleum Engineering, College of Engineering, Afe Babalola University, Ado-Ekiti, Ekiti State Nigeria. H has been a lecturer for over six years in which he has supervised over twenty student research projects at both undergraduate and postgraduate levels in Chemical Engineering. His area of research interests are centered on catalysis, renewable energy, separation processs, and environmental technologies.