In this study, process intensification was carried out using lipase catalyzed transesterification of waste cottonseed oil (WCSO) with ethanol in the presence of ultrasonication. A maximum conversion of 98.7% was observed for ultrasound assisted transesterification. The optimum process conditions were ethanol to oil molar ratio of 4.5:1, a reaction temperature of 45°C, enzyme loading of 5 wt%, a reaction time of 6 h, ultrasonic amplitude of 40% and the duty cycle of 15 s ON and 15 s OFF. The influence of ultrasound makes the process efficient because of an effective reduction in reaction time to 6 h with the least catalyst dosage and power consumption. Reusability tests of the catalyst were conducted after separating the immobilized Rhizopus oryzae lipase. The regenerated lipase catalyst was found to have better reusability up to the fourth cycle and the produced biodiesel was within the ASTM D6751 standard. Furthermore, the ultrasound assisted process under mild operating conditions did not affect the immobilized enzyme. It was clearly observed that ultrasonication is faster and effective for biodiesel conversion using the immobilized lipase catalyzed transesterification reactions.

在这项研究中，在超声波作用下，利用脂肪酶催化的废棉籽油（WCSO）与乙醇的酯交换反应进行了工艺强化。超声辅助的酯交换反应观察到最大转化率为98.7％。最佳工艺条件为：乙醇与油的摩尔比为4.5：1，反应温度为45°C，酶负载为5 wt％，反应时间为6 h，超声振幅为40％，占空比为15 s ON并关闭15 s。超声的影响使反应时间有效减少到6小时，同时催化剂用量和功耗最小，从而使该过程高效。分离固定的米根霉后进行催化剂的可重复使用性测试脂肪酶。发现再生的脂肪酶催化剂在第四个循环之前具有更好的可重复使用性，并且所生产的生物柴油在ASTM D6751标准之内。此外，在温和的操作条件下进行的超声辅助过程不影响固定化酶。清楚地观察到，使用固定化的脂肪酶催化的酯交换反应，超声处理对于生物柴油的转化更快且有效。