A Low-Energy Hybrid Approach for .Efficient Lipid Recovery from Auxenochlorel/a protothecoides

Microalgae are promising feedstocks for renewable fuels and biobased products, but energy­ intensive downstream processing remains a major challenge for large-scale commercialization. In particular, cell disruption significantly contributes to the overall cost and energy demand of lipid recovery. This study explores a hybrid strategy that combines biological cell-wall weakening with mild physical disruption to improve lipid extraction efficiency while reducing energy input. The approach employs dark-anoxic (DA) incubation to induce endogenous autolytic processes that biologically weaken the cell wall prior to pulsed electric field (PEF) or high-pressure homogenization (HPH) treatment. The effectiveness of the strategy was evaluated by comparing extraction performance with PEF and HPH treatments applied directly to untreated biomass. PEF treatment w_ithout DA pre-treatmerit required a specific energy input of 150 kJ L-1 to achieve high lipid recovery after 2 h of incubation. Lower energy inputs resulted in reduced extraction efficiency, even when the incubation period was extended to 24 h. In contrast, DA-treated biomass incubated at 38 °C achieved substantially higher lipid extraction yields using only 25 kJ L-1 and a 2 h incubation. ... mehrSimilar improvenients were observed with HPH, where a single pass was sufficient to significantly enhance extraction efficiency. Analysis of total lipid content and fatty-acid composition confirmed that DA incubation did not induce lipid degradation or alter the fatty acid distribution. Overall, the results demonstrate that biological pre-treatment can markedly reduce the energy requirements of downstream processing while maintaining product integrity. These findings highlight the potential of integrating biological pre-treatment with mild disruption to enable more sustainable and energy-efficient microalgal biorefinery process.