超临界CO2夹带乙醇萃取裂殖壶藻油脂的工艺研究

Technical Study on Lipid Extraction from Schizochytrium sp. Using Supercritical CO2 with Ethanol

研究了超临界CO2夹带乙醇流体从裂殖壶藻Schizochytrium sp.中提取富含DHA油脂的新工艺。基于气液相平衡性质,确定了夹带剂乙醇的添加范围,并对提取过程进行动力学分析,确定了二氧化碳的使用量。通过中心组合设计的响应面优化试验,获得了最佳提取工艺条件:温度52℃、压力38 MPa、乙醇摩尔比0.04。该条件下,微藻油脂的回收率约为88.2%,显著高于纯超临界CO 2萃取的回收率(71.9%)。根据Peng-Robinson方程考察了混合流体的密度变化对油脂溶解度的影响,部分解释了操作条件对油脂回收率的影响。脂肪酸组成分析显示,新工艺得到的油脂中的DHA质量分数约为39.9%,略高于传统工艺。由此可知,超临界CO 2夹带乙醇流体是一种极性范围广、溶解能力强的绿色提取介质,非常适用于中性微藻油脂的提取。

A novel process for extracting DHA-rich lipid from Schizochytrium sp.using supercritical CO2 with an entrainer,ethanol(scCO2+EtOH)was studied.The estimation of molar fraction range of ethanol depended on the thermodynamic data of the vapor(CO 2)-liquid(ethanol)equilibrium reported in the literatures.The total amount of CO 2 added was determined based on the kinetic analysis of the extraction process.The model equation was constructed successfully according to the response surface trials on basis of central compositedesign(CCD),presenting the optimal operation conditions including temperature of 52℃,pressure of 38 MPa and ethanol molar fraction of 0.04 mol/mol.The maximum recovery of microalgae lipid using new method reached around 88.2%significantly higher than that of pure supercritical CO 2 extraction(71.9%).Furthermore,Peng-Robinson equation was employed for calculating the densities of mixed fluid and the variation of fluid density with respect to the relevant parameters possibly influenced the solubility of microalgae lipid,partially explaining the impacts of operating conditions on lipid recovery.Chemical compositions of microalgae lipids based on gas chromatography showed microalgae lipidextracted by scCO 2+EtOH contained 39.9%of Docosahexaenoic acid(DHA),higher than that obtained by traditional techniques.Besides,it could be concluded that scCO 2+EtOH fluids have potential to be developed as a promising technique for extracting medium polar lipid from microalgae species dueto their own extensive polarity range,prominent solubility as well as environmentally friendly feature.