Enhancing biodiesel production via liquid Yarrowia lipolytica lipase 2 in deep eutectic solvents

With the rapid development of effective overexpression of enzymes, the process of liquid lipase catalysis of biodiesel can be concerned in a commercial viewpoint. The main bottleneck is to achieve high yield of biodiesel under a high water content. In this research, firstly, liquid Yarrowia lipolytica Lipase 2 was used to catalyze synthesis of biodiesel and 91.8% yield was obtained in the optimized reaction conditions after 24 h of reaction at 40 °C, water content 30 wt% (water/oil, w/w) and 1500 U/g oil of lipase dosage. To further improve the biodiesel yield, a deep eutectic solvent based on choline chloride and glucose was synthesized and optimized in terms of addition amount and water content, and the highest biodiesel yield of 98.5% was then achieved. The dynamics of each component during the reaction process were totally investigated, and found it was the addition of deep eutectic solvent that led to a deeper completion of the transesterification reaction. It also improved the reusability of the enzyme with a maximum biodiesel yield of 99.6% at the second reuse batch. This study demonstrates that deep eutectic solvent addition strategy has great potential for the commercialization of liquid lipase-catalyzed biodiesel production.