Hee-Yong Shin, Sang-Hyeok Shim, Young-Jin Ryu, Ji-Hyun Yang, Sang-Min Lim, and Choul-Gyun Lee

Hee-Yong Shin†, Sang-Hyeok Shim†, Young-Jin Ryu, Ji-Hyun Yang,Sang-Min Lim, Choul-Gyun Lee*
National Marine Bioenergy R&D Consortium & Department of Biological Engineering, Inha University, Incheon 22212, Korea
Tel: +82-32-872-7518; Fax: +82-32-873-7518 E-mail: leecg@inha.ac.kr
†The first two authors contributed equally to this work.

Received: 10 October 2017 / Revised: 28 January 2018 / Accepted: 3 February 2018
© The Korean Society for Biotechnology and Bioengineering and Springer 2018

Abstract

Lipid extraction is a critical step in the downstream processing of biodiesel production from microalgae. Solvent extraction using mixtures of non-polar and polar solvents is one of the most well-known processes for this purpose. Hexane is the most common solvent of choice for large-scale lipid extractions due to its technical and economic advantages, especially its high selectivity toward lipids and low cost. In this study, extractions using mixtures of hexane and polar solvents were evaluated for their performance in order to develop a more efficient method for large-scale lipid extraction from microalgae.
The combination of hexane and methanol resulted in the highest fatty acid methyl ester (FAME) yield for lipids from Tetraselmis sp. The effects of extraction conditions, including proportions of methanol to hexane, ratios of total solvent volume to dry biomass, and extraction time, on extraction yields were evaluated to determine optimum conditions providing higher lipid and FAME yields. The optimal conditions were as follows: proportion of hexane to methanol of 1:1, ratio of total solvent volume to dry biomass of 10 mL/g, and extraction time of 120 min. Finally, the selected solvent mixture and optimal conditions were applied to larger scale extraction experiments with scale-up factors of 10, 50, and 100. FAME yields of large-scale extractions were almost completely consistent with increasing scale-up factors. The results of this study suggest that a hexane and methanol mixture is a promising solvent for
large-scale lipid extraction from microalgae.

Keywords

lipid extraction, Tetraselmis sp., microalgae, hexane-based solvent mixture