Lipases in Green Chemistry: Deep Eutectic Solvents (DES) as New Green Solvents

Robust and Continuous Lipase-Catalyzed Reactions in Deep Eutectic Solvents: Low Viscosity and Double CLEA-LentiKats Immobilization (CLEA-LK-Lipases)

Deep Eutectic Solvents (DES) are used as reaction media for lipase-catalyzed esterifications in continuous devices. In particular, DES may be useful for lipophilization-like reactions involving substrates with unpaired solubilities. Aspects to be considered are the viscosity of the solvent, as well as the stability of the enzyme in the non-conventional media. The viscosity can be decreased by adding buffer as cosolvent (up to 20% v/v) and keeping the non-conventional nature. Lipases can be stabilized by following a double immobilization pattern, comprising CLEA formation and entrapment in LentiKats^®. The low viscosity and high stability of the CLEA-LK-lipase enable the use of DES under flow conditions.

The extraction of phenolic acids and polysaccharides from Lilium lancifolium Thunb. using a deep eutectic solvent

Establishing a fast and effective extraction method for herbs is beneficial for the determination of their main compounds and estimating their quality. In this study, deep eutectic solvents (DESs) were optimized to simultaneously extract three main types of phenolic acids, i.e., regaloside B, regaloside C, and regaloside E, and polysaccharides from the bulbs of Lilium lancifolium Thunb. Based on the optimized extraction conditions, i.e., an extraction temperature of 50 °C, an extraction time of 40 min, a solid-liquid ratio of 1 : 25, and a ratio of water in the DES of 20%, the extracted amounts of regaloside B, regaloside C, and regaloside E reached 0.31 ± 0.06 mg g-1, 0.29 ± 0.03 mg g-1, and 3.04 ± 0.38 mg g-1, respectively. The extraction efficiencies were higher than those obtained using conventional organic solvents. Next, the polysaccharide levels were measured and compared with those obtained using a conventional hot water extraction method, and equivalent extraction efficiencies were obtained with the conventional hot water extraction method. This study provides a new application of deep eutectic solvents (DESs) for simultaneously extracting phenolic acids and polysaccharides from the bulbs of L. lancifolium Thunb. Considering the biodegradability and pharmaceutical acceptability, DESs as a class of green solvents could have wide applications in the extraction of natural products.