Studies on the lipase-catalyzed esterification of alkyl oleates in solvent-free systems

The alkyl oleates were prepared by esterification of oleic acid with alkyl alcohols catalyzed by the lipase from Candida sp. 99-125 in solvent-free system. The influence of several factors, including enzyme concentration, temperature, molar ratio between oleic acid and alkyl alcohols, the structure of alcohols and water content, was also investigated. The results indicated that the reactions catalyzed by Candida sp. lipase at 20 °C, in the presence of 5% (w/w) lipase, on the molar ratio of 1:1 between oleic acid and alcohols, afforded products in high yield and showed high selectivity to primary alcohols. The enzymatic synthesis gave purer products, compared with the conventional chemical synthesis. The lipase from Candida sp. 99-125 was identified to be an effective catalyst in the esterification of alcohol and oleic acid at low temperature.

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► The factors effecting the lipase-catalyzed esterification of oleates are studied.
► The lipase from Candida sp. 99-125 has high activity at ambient temperature with more economical acid/alcohol ratio.
► Lipase from Candida sp. 99-125 is identified to be a cost-saving catalyst for esterification in the further industrial application.