Cheese whey permeate gets a new look by turning into biosurfactants

Cheese whey is the main waste stream of dairy industry accounting for ~11 million tons in 2019 in Italy.1 After protein recovery, the resulting whey permeate (WP) contains mainly lactose (50 g/L) that can be upcycled, thus allowing the full valorization of this by-product. In this project, an integrated bioprocess was set-up for the synthesis of Sugar Fatty Acid Esters (SFAE) which are valuable non-ionic surfactants.2 WP was used both as a feedstock for enzymatic biotransformations3,4 as well as a fermentation medium for oleaginous yeasts5 to produce the sugarbased polar “heads” and the lipid “tails” of SFAE, respectively. As a proof-of-concept, 6-O-palmitoyl-1-O-butyl-β-D-galactopyranoside was prepared by a two-step enzymatic cascade: WP was submitted to a transglycosylation reaction in n-BuOH catalyzed by an immobilized b-galactosidase affording n-butyl-β-D-galactopyranoside, which was then esterified with palmitic acid in a solvent-free system by an immobilized lipase. The use of microbial lipids as raw materials for the esterification step is now in progress. Interfacial features and W/O emulsifying properties of the synthesized SFAE were evaluated. Acknowledgements This work was financially supported by Cariplo Foundation (Italy) (call: “Circular Economy for a sustainable future 2020”, project BioSurf, ID 2020-1094). References [1] www.clal.it; [2] Ahumada et al., Front. Bioeng. Biotechnol., 2020, 8, 859; [3] Semproli et al., submitted; [4] Sangiorgio et al., Colloid Interface Sci. Commun., 2022, 48, 100630; [5] Donzella et al., Fermentation, 2022, 8, 341.