不同亚临界溶剂从微拟球藻湿藻泥中提取油脂

以微拟球藻(Nannochlorsis sp.)湿藻泥为原料，研究了亚临界乙醇、亚临界乙醇-正己烷共溶剂及硫酸辅助亚临界乙醇-正己烷共溶剂3种萃取体系对微藻油脂提取的影响. 结果表明，亚临界乙醇-正己烷比亚临界乙醇对湿藻细胞有更高的油脂萃取率和低的溶剂用量，加入少量硫酸可进一步提高油脂的提取率、降低溶剂用量. 微拟球藻湿藻泥(含水约70%)优化提取条件为，正己烷/乙醇体积比3:1，液固比(溶剂/藻细胞干重)7 mL/g，加入藻细胞干重6%的硫酸，1.5 MPa下90℃萃取30 min，在此条件下油脂提取率可达90%以上. 3种萃取体系获得的微藻油脂均以甘油三酯为主，甘油三酯的脂肪酸主要为C16:0, C18:1和C16:1，其中硫酸辅助亚临界共溶剂萃取的微藻油脂中甘油三酯含量最高，约占总脂的86%以上.

Subcritical Extraction of Lipids from Wet Microalgae Paste of Nannochlorsis sp.

The extraction of lipids from wet microalgae paste of Nannochlorsis sp. with subcritical extraction method of ethanol, ethanol-hexane co-solvents, and ethanol-hexane co-solvent added with sulfuric acid was investigated. The results showed that at the same extraction recovery rate of lipid of about 85%, subcritical ethanol-hexane co-solvent extraction only required 10 mL/g solvent to dry algal biomass, compared with 30 mL/g by subcritical ethanol extraction. The addition of drops of sulfuric acid to subcritical ethanol-hexane co-solvent extraction could further modify the extraction rate of lipids. The optimum extraction conditions of wet algal paste of Nannochlorsis sp. were suggested as follows: ratio of hexane to ethanol 3:1(j), ratio of solvent to algal biomass 7 mL/g, sulfuric acid to biomass 6%(w), 1.5 MPa of pressure and 30 min extraction at 90℃, at which the recovery rate of lipid oil from wet algal paste could reach 90%. Triglyceride was the main component of the extracted lipid oil. Relatively, more triglycerides (about 86%) in extracted lipid by subcritical ethanol-hexane co-solvent added with sulfuric acid were obtained. The fatty acids profile of triglycerides revealed that C16:0 (35.5%), C18:1 (24.56%) and C16:1 (22.08%) were dominant.