Deep eutectic solvents: a new tool for Phospholipase D-catalyzed preparation of polar head modified phospholipids

In the recent years the demand for new synthetic approaches with reduced environmental impact is highly present in the political agenda. In this context, the use of new protocols involving biocatalysis as well as the investigation of greener suitable solvents in the chemical modification of organic materials fits perfectly the research focused on the achievement of the Sustainable Development Goals. To this end the potential use of Deep Eutectic Solvents (DESs) in the preparation of polar head modified phospholipids (PLs) with phospholipase D (PLD)-catalyzed biotransformations has been investigated. PLs constitute the major components of biological membranes and play a fundamental role in many cellular functions. For that reason, they constitute the topic of many areas of biomedical research as drug-delivery systems, pro-drugs, diagnostic markers and therapeutic agents. Additionally PLs possess industrial interest as surfactants, food stabilizers, natural emulsifiers and detergents. The biological activity of PLs mainly depends on the chemical identity of the polar head. In this mainframe the synthesis of polar head modified PLs for targeted applications is of fundamental importance. In this work natural phosphatidylcholine (PC) has been submitted to PLD-catalyzed transphosphatidylation using new reaction media composed by mixtures of DESs and buffer. PC appeared to be highly soluble therein avoiding the use of other toxic organic solvent which was usually necessary in these reactions. Moreover, DES medium inhibited quite completely the hydrolysis side-reaction driving the reaction toward transphosphatidylation and making the final new PLs easier to recover by simple precipitation. The presented results appeared to pave the way to the development of further studies on DES-mediated PLs preparations in a sustainable perspective.