| Summary: | Pulsed Electric Field (PEF) pre-treatment, applied on fresh microalgae Auxenochlorella
protothecoides, induces spontaneous release of a substantial water fraction and enables
subsequent lipid extraction using ethanol-hexane blends. In this study, fresh microalgae
suspensions were treated with PEF and incubated under inert conditions. Incubation promotes the
release of ions and carbohydrates and increases the yields of subsequent lipid extraction thus
enabling a considerable reduction of PEF-treatment energy. With a 20 hour incubation period at
25°C, almost total lipid extraction is achieved with a specific PEF-treatment energy of only
0.25 MJ/kg DW . Incubation on ice remains beneficial but less efficient than at 25°C. Additionally,
incubating microalgae cells in suspension at 100 g DW /L or in a dense paste, was almost equally
efficient. Correlation between the different results suggests that spontaneous release of ions and
carbohydrates facilitates more successful lipid extraction. A direct causality between the two
phenomena remains to be demonstrated.
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