This article presents a new processing approach to perform lipid extraction on the wet microalgae A. protothecoides using nonpolar solvents or solvents of low polarity. It was demonstrated that solvents such as hexane, heptane, or 2-butanol exhibit a negligible extraction efficiency (<4% of total lipid content) when added to the pulsed-electric field (PEF)-treated and dewatered biomass slurry. In contrast, extraction efficiency after PEF treatment could substantially be increased by adding water and solvent to the biomass slurry. For this case, additional water admixture during extraction enabled to recover 67.3, 62, or 82.3% of the total lipid content, respectively. When utilizing methyl terbutyl ether (MTBE), ethylacetate, and 2-methyltetrahydrofuran (2-MeTHF) as extracting solvents, the yield increase by additional water admixture is far less pronounced. In all cases, the extraction process was performed after a PEF treatment using 1.50 MJ/kg_DW plus 24-h incubation and 20 h of mixing time with the solvents and the solvent/water mixtures. Estimations on the energy required for the whole downstream process showed that this process variant allows an energy consumption of 31.48 MJ/kg_biodiesel at maximum and 7.98 MJ/kg_biodiesel at minimum. The low energy requirements (only <22% of the energy content of the lipids) open pathways to energetical applications of microalgae lipids.

中文翻译：

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过量的水能够使用不混溶溶剂从湿脉冲电场处理的原壳A. protothecoides微藻中高效提取脂质


本文提出了一种使用非极性溶剂或低极性溶剂对湿微藻 A. protothecoides 进行脂质提取的新处理方法。结果表明，当添加到脉冲电场 (PEF) 处理和脱水的生物质浆料中时，己烷、庚烷或 2-丁醇等溶剂的提取效率可忽略不计（<总脂质含量的 4%）。相比之下，通过向生物质浆料中添加水和溶剂，可以大大提高 PEF 处理后的提取效率。对于这种情况，在提取过程中添加额外的水混合物能够分别回收总脂质含量的 67.3%、62% 或 82.3%。当使用甲基叔丁基醚 (MTBE)、乙酸乙酯和 2-甲基四氢呋喃 (2-MeTHF) 作为萃取溶剂时，额外添加水混合物对产率的增加并不那么明显。在所有情况下，提取过程均在使用 1.50 MJ/kg _DW 的 PEF 处理加上 24 小时孵育以及与溶剂和溶剂/水混合物的 20 小时混合时间后进行。对整个下游工艺所需能量的估算表明，该工艺变体允许的能耗最大为 31.48 MJ/kg _biodiesel ，最小为 7.98 MJ/kg _biodiesel 。低能量需求（仅<脂质能量含量的22%）为微藻脂质的能量应用开辟了途径。