Abstract: The objective of the work was to study the enzymatic production of fatty acid ethyl esters (FAEEs) which were synthesized from soybean oil and ethanol by the immobilized lipase Candida sp. 99-125. The effects of different conditions such as water content, solvent content, enzyme amount and temperature on the esterification reaction were studied for optimizing the process. With a three-stepwise addition of ethanol into the reaction system, the maximum yield of FAEEs of 96.8% was obtained after 12 h under the following optimized conditions: 12.5%(w) water, based on the weight of soybean oil, 3 mL/g n-hexane as solvent, 20%(w) lipase and temperature 40℃. Moreover, the immobilized lipase could be used continuously for 14 batches with high yield of FAEEs over 70%.

Key words: biodiesel, ethanol, fatty acid ethyl esters, lipase, optimization

摘要： 探讨了酶法合成脂肪酸乙酯作为生物柴油的可行性. 以大豆油和乙醇为原料，利用本实验室自制的固定化Candida sp. 99-125脂肪酶催化反应，深入研究水含量、溶剂量、脂肪酶量及反应温度等因素对酶法合成脂肪酸乙酯的影响. 结果表明，以大豆油质量为基准，在水含量为 12.5%(w)、溶剂正己烷为3 mL/g、脂肪酶量为20%(w)、温度40℃的优化反应条件下，3次流加乙醇，170 r/min摇瓶反应，12 h后可以达到96.8%的最高酯得率. 进一步研究表明，在此优化反应条件下，连续使用14批脂肪酶酯得率可保持70%以上.

关键词: 生物柴油, 乙醇, 脂肪酸乙酯, 脂肪酶, 优化