Evaluation of deep eutectic solvents as new media for iCALB–catalyzed reactions

Some lipases preserve good activity in organic solvent and their ability to catalyze transesterification reactions in organic media is known and well documented. However, most organic solvents can be environmentally damaging or toxic. Therefore, in a context of green chemistry a number of studies have attempted to resolve this dramatic environmental impact and try to realize lipase–catalyze reaction in green solvent. Ionic liquids were the first potentially alternatives to organic solvents for biotransformation; they are non volatile, thermally stable and have high solvation properties. Nevertheless, the limitations of ionic liquids are their cost, toxicity and the need for high purity. Deep eutectic solvents (DESs) are a new class of solvent typically formed by mixing an ammonium salt and a hydrogen–ond donor. Like ionic liquids, DESs often have melting points close to room temperature, low volatility and high thermal stability. Unlike them, they are biodegradable, cheap and very easy to prepare. In this context, it will be very interesting to develop lipase–compatible DES from inexpensive and biodegradable cholinium salt. Therefore, in order to know the potential of DESs to be friendly–media for lipase–catalyzed reaction we investigated iCALB compatibility in eutectic solvents with a focus of the activity, selectivity and stability after long incubation–time