Novel Applications of Sophorolipid-Derived Hydroxy Fatty Acids and their Derivatives

Sophorolipids (SL) are naturally produced microbial glycolipids that are composed of a hydrophilic (sophorose) moiety and a hydrophobic (hydroxy fatty acid) moiety, resulting in an amphiphilic molecule with immense application potential. Following chemical deconstruction of the sophorolipid molecule mixtures, unique hydroxy fatty acids were obtained and assessed for possible new applications as antimicrobial agents and oleogelators. Amide derivatives of the hydroxy fatty acids were produced using pyrrolidine, resulting in an antimicrobial activity against Listeria monocytogenes, various Streptococcal strains, and Bacillus sp. While these amide derivatives were less efficient compared to lauric acid pyrrolidine (LAPY; control), results indicate a possible new use for the SL-derived hydroxy fatty acids as antimicrobial agents. Another possible application for SL-derived hydroxy fatty acids is in the formation of oleogels. Oleogels are solid fat alternatives that are formed when a low-molecular weight gelator is melted and recrystallized in a liquid oil, followed by self-assembly into a crystalline network that traps the oil forming a viscoelastic semi-solid compound. They are typically produced from 12-hydroxy-stearic acid, which originates from hydrogenated ricinoleic acid. However, ricinoleic acid is obtained from the castor plant, characterized by the occurrence of ricin, a dangerous toxin, in its seed. SL-derived hydroxy fatty acids and methyl esters were also used to make soybean oil oleogels with minimum gelation concentrations between 5% and 10%, thus providing potentially viable alternatives for oleogel formation. In this presentation, these 2 innovative possibilities will be discussed for supplementary uses of the SL-derived hydroxy fatty acids in new applications.