In-situ phase separation by using surface modified filter for microalgal lipids extraction

Abstract

Lipid extraction process to recover microalgal lipids for biofuel includes steps for separating emulsified mixture of organic solvent, aqueous solution, and lipid-extracted algae. Gravitational settler and centrifugation, traditional separation methods, require an alternative because settler cannot handle emulsion and centrifugation is energy and cost-intensive. Here we develop in-situ phase separation method by using surface modified filter and utilize it in microalgal lipids extraction. After hydrothermal treatment of Chlorella sorokiniana HS1 with acid catalyst, we extracted lipids by using hexane as solvent. At the same time, aqueous phase was removed by hydrophilic pHEMA filter to increase the efficiency of lipid extraction and then extracted lipids were recovered by hydrophobic pPFDMA filter. 87% of hexane extractable lipids were recovered by solely using pPFDMA filter. Finally, we recovered 94 % of hexane extractable lipids, 4 g/L of monosaccharide and 41.3 g/L of amino acid solution after residue treatment. Our method is energy-efficient because phase separation is driven without external energy and cost-effective because additional separator units are not necessary, thus demonstrating that our extractor is applicable to microalgal biorefinery