From Microalgae to Jet Fuel: A Low-Energy Disruption Strategy for Efficient Lipid Recovery based on combined PEF treatment and Autolysis

A low-energy hybrid disruption strategy was developed to enhance lipid extraction from Auxenochlorella protothecoides while reducing energy demand and solvent use. The approach combines dark-anoxic (DA) autolytic incubation with physical treatments, namely pulsed electric fields (PEF) or high-pressure hömogenization (HPH), to biologically weaken the cell wall prior to disruption. PEF-assisted extraction alone required high energy input (150 kJ L-1) or prolonged incubation (24 h) to achieve high recovery. In contrast, the hybrid method significantly improved performance: a short DA incubation (2 h, 38 °C) combined with low-energy PEF (25 kJ L-1) iricreased lipid recovery from ~59°/o to ~72°/o, while the full DA+PEF sequence reached ~80o/o at only 0.25 MJ kg- dry weight. A comparable yield (~79o/o) was obtained using DA combined with single­ pass HPH; however, the energy demand (~9 MJ kg-1) ) was substantially higher. lmportantly, lipid content and fatty-acid composition remained unchanged du ring autolytic treatment, confirming no intracellular lipid degradation. Overall, the results show that DA-ind.uced autolysis coupled with low-energy PEF enables efficient and scalable lipid recovery, reducing process energy by over 80o/o compared to mechanical disruption. ... mehr_This approach provides a promising raute toward sustainable microalgal biorefining and supports low-energy targets for biofuel production.