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Commercial lipase from Thermomyces lanuginosus (TLL) has been immobilized on glutaraldehyde-activated rice husk particles via covalent attachment. The immobilized biocatalyst was used to synthesize cetyl oleate (wax ester) via direct esterification of oleic acid and cetyl alcohol. The influence of relevant factors on ester synthesis, such as presence or lack of hydrophobic organic solvents and reaction time has been evaluated. Under optimal experimental conditions, it was observed maximum ester conversion of 90.2 ± 0.6% in 9 h of reaction time in hexane medium by using 1 M of each reactant (cetyl alcohol and oleic acid). Similar conversion (91.5 ± 0.8%) in a solvent-free system was also obtained within 24 h of reaction. The biocatalyst retained 85% of its initial activity after twelve cycles within 9 h of reaction in hexane medium. The physicochemical properties of purified ester have been determined in accordance with ASTM standards. The results indicate that the prepared biocatalyst has great potential for wax ester synthesis due to its satisfactory catalytic activity and operational stability.

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