Chemoselective deacetylation of hydrophobic glycophenols by lipase PS enhanced with bovine serum albumin

Abstract

Enzymatic methods leading to the preparation of biologically active glycophenols are attracting increasing interest due to their selectivity and sustainability. In this study, a series of hydrophilic and hydrophobic 4-O-acetylferulic acid sugar esters was prepared using a combination of chemical and enzymatic approaches. During the investigation of chemoselective deacetylation of the phenolic groups in these esters, a pronounced cooperative effect between Lipase PS and bovine serum albumin (BSA) was observed in a biphasic MTBE-water system. In the presence of BSA, Lipase PS more rapidly and selectively deacetylated the phenolic acetyl group of hydrophobic substrates. In contrast, no rate enhancement was observed for more polar substrates bearing free hydroxyl groups. Protecting groups on the carbohydrate moiety remained unaffected, and the ester bond between ferulic acid and the sugar was preserved. The accelerating effect of BSA on hydrophobic substrates is attributed to its surface-active properties, which increase the interfacial area through the formation of stable emulsions. Given that the intrinsic acetylesterase activity of BSA is approximately 300-fold lower than that of Lipase PS, BSA alone is not capable of effective deacetylation. These findings highlight the potential of surface-active proteins to improve biocatalytic transformations of hydrophobic substrates while avoiding purification challenges associated with low-molecular-weight surfactants.

Keywords: Bovine serum albumin; Chemoselective two-phase deacetylation; Ferulic acid sugar esters; Lipase PS.