Green deep eutectic solvent assisted enzymatic preparation of biodiesel from yellow horn seed oil with microwave irradiation

Abstract In this study, biodiesel was produced from yellow horn seed oil through transesterification using immobilized enzyme Novozym 435 in green deep eutectic solvents (DESs) medium with microwave irradiation method. Eleven DESs were prepared, DES-2 (molar ratio chloride/glycerol 1:2) was proved to be the most effective solvents. Under the optimum conditions, 8% dosage of Novozym 435, methanol/oil ratio 6:1, microwave power 400 W, temperature 50 °C, and reaction time 120 min, 95% conversion yield was achieved. Furthermore, recovered enzymes were used for four successive reaction cycles without any significant loss of enzyme activity. The usage of DES could greatly retain the enzyme activity, increase conversion yield, and make it easy to separate the product. In general, preparation of biodiesel with enzyme in green DESs would be an alternative for traditional transesterification method.