Prospect of Deep Eutectic Solvents in Lactic Acid Production Process: A Review

This article reviews the potential application of deep eutectic solvents (DESs) for lactic acid production from lignocellulosic materials where DESs could be used as both preatreatment and extraction solvents as an alternative to the conventional organic solvents and ionic liquids. From literature survey, conventional methods currently explored for lactic acid (LA) production have several drawbacks of low yield, impure LA, low distribution coefficient, high cost of solvents, and non-recyclability of the solvents. Deep eutectic solvents (DESs) is paramount in LA production as  could enhance biotechnological development in obtaining higher yield of LA through better recovery as compared with the conventional extraction methods. The prospects of using DESs for LA production is huge in that, their unfavorable properties can be overcome by tailoring them through changing the nature of the molar ratio of hydrogen bond acceptor (HBA) to hydrogen bond donors (HBD), by adding appropriate amount of water if the DESs is highly viscous, by changing temperature or pressure and formation of ternary deep eutectic solvent through combinations of more components. DESs differs from the conventional organic solvent and ionic liquids as it offers several advantages  of recyclability, biodegradability, less volatile, non-toxic, non-flammability, high tuneability, high dissolution capability, ease, short time of preparation, and low costs as both pre-treatment and extraction solvents, but its feasibility for LA production has not been tested yet.