Exploring cheese whey permeate as raw material for the chemoenzymatic synthesis of bio-based emulsifiers

Sugar fatty acid esters (SFAEs) are a group of non-ionic surfactants which exhibited excellent interfacial tension reduction capability, biodegradability, and low toxicity. Moreover, they can be obtained from renewable raw materials, thus answering to the need of green and circular chemistry 1. Herein, cheese whey permeate (CWP), the main waste stream of dairy industry, was used as starting material to produce bio-based surfactants. Specifically, CWP was enzymatically hydrolysed into a mixture of glucose and galactose which was then submitted to a two-step chemoenzymatic synthetic protocol (Fischer glycosylation followed by solvent-free enzymatic esterification) 2. The first step of sugar derivatization was not straightforward since several parameter influenced both yield and isomeric ratio. Therefore, the reaction conditions were optimized thanks to a chemometric study. In the second step, an enzymatic esterification reaction was conducted leading to an isomeric mixture of n-butyl 6-O-palmitoyl-D-glycosides. The surfactancy of the obtained mixture was deeply investigated in terms of both static and dynamic interfacial tension reduction ability and water-in-sunflower oil (W/O) emulsion stabilization capacity over time 3. Additionally, computational studies were conducted to study the role of the ring size on the final emulsifying properties of the isomeric mixture 4.