Lipase‐catalyzed reactions involving thia fatty acids and ester derivatives

Abstract

AbstractEnzymatic hydrolysis of synthetic methyl 5‐, 9‐, and 12‐thiastearates in aqueous media withCandida cyclindracea or porcine pancreatic lipases gave the corresponding fatty acids in 70–100% yield. Hydrolysis of the 3‐ and 4‐positional isomers gave only 15–25% of the free thia fatty acids, suggesting discrimination against these isomers by lipases. No lipolysis was achieved with methyl 2‐thialaurate under a range of reaction conditions. Esterification of the 3‐, 4‐, 5‐, 9‐, and 12‐thiastearic acids withn‐butanol inn‐hexane using Lipozyme (immobilizedRhizomucor miehei) as the biocatalyst gave the corresponding butyl esters in 80–95% yield. Interesterification (acyl exchange) of triolein with methyl 9‐thiastearate in the presence of Lipozyme showed the incorporation of 9‐thiastearoyl chain at only one of the α‐positions of triolein. In the case of methyl 2‐thialaurate, no lipase‐catalyzed acyl exchange reaction was possible. This study showed that the position of the sulfur atom in thia fatty esters affects the lipase‐catalyzed hydrolysis and interesterification reactions.