微藻总脂定量分析方法的比较研究

Comparative study of quantitative analysis methods for microalgae total lipid

从总脂含量、脂肪酸甲酯(FAMEs)得率和脂肪酸组成等方面对4种总脂定量提取方法进行了比较研究。结果表明:超声波辅助正己烷-乙酸乙酯提取法、三氯甲烷-甲醇提取法、二甲亚砜(DMSO)-甲醇/正己烷-乙醚分步提取法和正己烷索氏抽提法测定小球藻总脂含量,经过破壁处理,总脂含量分别为32.95%、26.81%、29.60%和25.17%,未经过破壁处理,总脂含量分别为16.30%、17.17%、21.81%和8.72%,两组测定结果差异极显著,表明从厚壁微藻提取总脂必须对藻粉进行破壁处理。4种方法提取总脂的脂肪酸甲酯得率分别为24.20%、26.19%、28.02%和21.23%,除正己烷索氏抽提法得率偏低外,其他3种方法得率相近,均能较完全地提取中性脂。正己烷索氏抽提法抽提1 h不能充分提取总脂。三氯甲烷-甲醇提取法和DMSO-甲醇/正己烷-乙醚分步提取法可以提取鲜藻总脂,而其他两种方法则不能。

Four quantification methods for microalgae total lipid were investigated by comparison of total lipid content, fatty acid methyl esters （FAMEs） yield and fatty acid composition. The results showed that the total lipid contents of disrupted dry cells from Chlorella pyrenoidosa by methods of n - hexane - ethyl acetate extrac- tion, chloroform - methanol extraction, DMSO - methanol/n - hexane - diethyl ether extraction and n - hexane Soxhlet extraction were 32.95%, 26.81%, 29.60%, 25.17%, respectively; while the total lipid contents of intact dry cells were 16.30%, 17.17%, 21.81%, 8.72%, respectively. The significant differences of total lipid contents between disrupted cells and intact cells indicated that cell disruption was necessary for total lipid extraction from microalgae with thick cell wall. The FAMEs yield （21.23%） was the lowest by the method of n - hexane Soxhlet extraction, and FAMEs yields for the other three methods were similar, 24.20%, 26. 19% and 28.02% ,respectively. The data showed that except for n - hexane Soxhlet extraction, the other three methods were able to extract neutral lipid completely. For the n -hexane Soxhlet extraction method with extraction time of 1 h, total lipid couldn＇t be extracted efficiently from disrupted microalgae cells. Themethods of chloroform -methanol extraction and DMSO - methanol/n - hexane - diethyl ether extraction were applicable to extract total lipid from fresh microalgae, however, the other two methods could not.