One of the difficulties of using microalgae for the production of biofuels is the development of an efficient and economically feasible process for oil extraction from these unicellular organisms. Current methodologies involve toxic solvents (such as chloroform, benzene and methanol, among others), high energy requirements and high capital cost. The extraction processes using organic solvents in a Soxhlet apparatus with or without the assistance of ultrasound irradiation have shown promising results. In this context, the main objective of this study was to improve the oil yield of Acutodesmus obliquus using different mixtures of ethanol and hexane. Ethanol to hexane volume ratios of 1:1, 2:1 and 1:2 (vol/vol) were used at 60 °C. The best extraction yield in relation to the total lipid content of the microalgae biomass was 92% for Soxhlet and 59% for ultrasonic irradiation using 1:2 (vol/vol) ethanol:hexane for extraction times of 12 and 2 h, respectively. These extraction yields were significantly better than those of the pure solvents, i.e., 24% and 217% higher than ethanol and hexane via Soxhlet and 55% and 68% higher than the ultrasound-assisted extraction procedure. The ethanol to hexane volume ratio of 1:2 (vol/vol) presented a superior performance in both Soxhlet and ultrasound-assisted extraction procedures by extracting a large amount of polar, non-polar and neutral lipids. Similar yields to the Soxhlet (12 h) with the ethanol:hexane 1:2 (vol/vol) solvent mixture were obtained with ultrasound (for 40 min) followed by Soxhlet (4 h) extraction leading to a reduction of 164% in energy consumption.

使用微藻生产生物燃料的困难之一是开发一种从这些单细胞生物中提取油的有效且经济上可行的方法。当前的方法涉及有毒溶剂（例如氯仿，苯和甲醇等），高能源需求和高投资成本。在索氏萃取仪中使用有机溶剂进行的萃取过程，无论是否进行超声波辐照，均显示出令人鼓舞的结果。在这种情况下，本研究的主要目的是提高斜切线虫的油产量。使用乙醇和己烷的不同混合物。在60°C下使用的乙醇与己烷体积比为1：1、2：1和1：2（体积/体积）。相对于微藻生物质的总脂质含量而言，最佳提取得率分别为：索氏提取法为92％，而使用1：2（vol / vol）乙醇：己烷进行12分钟和2 h的超声照射，则为59％。这些提取率明显高于纯溶剂，即通过索氏提取法分别比乙醇和己烷高出24％和217％，比超声辅助提取程序高出55％和68％。乙醇与己烷的体积比为1：2（体积/体积），通过提取大量极性，非极性和中性脂质，在索氏提取法和超声辅助提取程序中均表现出优异的性能。与乙醇：己烷1的索氏萃取（12 h）相似的产率