无溶剂系统中固定化脂肪酶催化废油脂转酯生产生物柴油

Transesterification of Waste Oil to Biodiesel in Solvent Free System Catalyzed by Immobilized Lipase

探讨了无溶剂系统中固定化脂肪酶Novozym 4 35催化餐饮业废油脂转酯生产生物柴油 .反应副产物甘油可吸附在固定化酶载体表面 ,采用丙酮洗涤除去甘油可提高酶的稳定性 .适宜的醇 /油摩尔比、酶用量、反应温度和摇床转速分别为 1,6 6U/g ,35～ 4 0℃和 15 0r/min ,不宜加水到反应体系中 .采用分步加入甲醇的方式可减轻甲醇对酶的毒害作用 .分别在反应进行到 6和 14h时用丙酮除去酶表面的甘油 ,然后按醇 /油摩尔比为 1的比例加入甲醇继续反应 ,反应 30h后产物中的脂肪酸甲酯含量为 88 6 % .连续反应 30 0h后 ,酶活性基本没有下降 .

The transesterification of waste oil to biodiesel in a solvent free system catalyzed by an immobilized lipase Novozym 435 was explored. The byproduct glycerol was found to be adsorbed on the support and the stability of the immobilized lipase was enhanced by rinsing the enzyme with acetone. The optimal reaction conditions such as molar ratio of methanol to oil, enzyme amount, temperature and shaking rate were 1, 6.6 U/g , 35～40 ℃ and 150 r/min , respectively. Water addition was not favorable for the reaction. A three-step methanolysis protocol was used to protect the immobilized lipase from inactivation by methanol. One molar equivalent of methanol was successively added at reaction time of 0, 6 and 14 h, by which a methyl ester content of 88.6% in the reaction mixture could be achieved after total reaction time of 30 h. Acetone was used to remove glycerol from the enzyme surface at each step. The enzyme showed no appreciable loss in activity after being continuously operated for 300 h.