Low-Energy Fractionation of Wet Microalgae Biomass by Combination of Autolytic lncubation and Pulsed Electric Field

Microalgae are promising feedstocks for sustainable biofuel and bioproduct production, yet the high energy demands of cell disruption and lipid .extraction remain key barriers to large-scale implementation. In this study, we would purpose to develop a low-energy hybrid treatment -method that improves lipid extractability from Auxenochlorella protothecoides (211-?a) while reducing both energy • consumption and solvent usage. The strategy couples an autolytic inct.Jbation with a subsequent pulsed electric field (PEF) treatment. Autolytic incubation exploits the cell's own autolytic enzymes under dark-anoxia (DA) conditions, leading to weakening of the cell wall structure. This biological pre-treatment allowed PEF to be applied at lower energy levels, contributing significantly to overall energy savings. To evaluate the effectiveness of the dev.eloped hybrid method, comparative experiments were conducted against standalone PEF treatment. When using PEF-assisted extraction alone, high energy input (150 kJ/L) was required to achieve high extraction yield with 2 h incubation. However, when using _lower energy inputs, a langer incubation period (24 h) was needed, but even then, the highest yield could not be achieved. ... mehrOn the other hand, the hybrid method achieved significantly higher extraction yield with lower energy input (25 _kJ/L) and a shorte·r incubation period (2 h). Total lipid content and fatty-acid composition remained unchanged after autolytic incubation, confirming that intracellular lipids were not degraded during the DA incubation. These results • demonstrate that pre-treated microalgal cells under DA enables efficient, scalable lipid extraction with lower energy input, providing a practical raute toward more sustainable microalgal biorefining.