Choline-based deep eutectic solvents for enzymatic preparation of biodiesel from soybean oil

In this study, we introduced choline-based deep eutectic solvents (such as choline chloride/glycerol at 1:2 molar ratio) as inexpensive, non-toxic, biodegradable and lipase-compatible solvents for the enzymatic preparation of biodiesel from soybean oil. Through the evaluation of different eutectic solvents and different lipases, as well as the study of reaction parameters (i.e. methanol concentration, Novozym 435 loading and reaction time), we were able to achieve up to 88% triglyceride conversions in 24 h. The enzyme could be reused for at least four times without losing much activity. Our results indicate that new benign eutectic solvents can be used as substitutes of toxic and volatile organic solvents in the enzymatic production of biodiesel from real triglycerides (such as soybean oil).