Enzymatic synthesis of glycerol and sucrose-palm oil fatty acid esters produced and their potency as antimicrobial agents

Abstract

Enzymatic synthesis of glycerol-palm oil fatty acid and sucrose-palm oil fatty acid esters was conducted using Candida rugosa lipase EC 3.1.1.3 in n-hexane. The palm oil fatty acid was obtained by hydrolyzing palm oil using KOH in 96% ethanol. The molar ratio of fatty acid to glycerol were varied, i.e. 1:1, 1:2, 1:3 and 1:4, while fatty acid to sucrose were 1:0.2, 1:0.4, 1:0.6 and 1:0.8. Conversion percentage of esterification was determined by titrimetric method. The highest conversion percentage was obtained at mole ratio 1:4 with the value of 42% for glycerol-palm oil fatty acid ester and at mole ratio 1:0.8 with the value of 24% for sucrose-palm oil fatty acid ester. Characterization esterification products by using FT-IR showed that the ester bond was formed as indicated at 1748 cm-1 for the absorption peak of C=O ester group of glycerol-fatty acid ester and 1734 cm-1 for sucrose-fatty acid ester. Both esters were then examined by antimicrobial assay. This study showed that glycerol-palm oil fatty acid ester can not inhibit the growth of Staphylococcus epidermidis and Propionibacterium acnes, while sucrose-fatty acid ester have ability to inhibit the growth of Staphylococcus aureus but not for Escherichia coli.