The use of lipases as biocatalysts in ester synthesis has been the object of growing interest. In addition to glycerol ester hydrolysis, lipases can catalyze a wide variety of esterification, transesterification and polyesterification reactions. The transesterification includes acidolysis, interesterification and alcoholysis. We consider in this report the application of lipases in the alcoholysis of brazilian vegetable oil in the production of fatty acid esters due to its importance as, for example, antifriction agents, food preservatives, emulsifiers and intermediates to produce a number of oleochemicals and fuel alternatives (biodiesel). In this work, enzymatic alcoholysis of castor bean oil with an immobilized lipase (Lipozyme IM) was accomplished using n-hexane as solvent. In order to maximize the esters production a Taguchi design was adopted varying temperature, water and enzyme concentrations in the reaction media and the oil:ethanol molar ratio. The reactions were monitorated by determining the glycerol production. An empirical model was built to evaluate the influence of the process variables on the conversion and afterwards the operating conditions that maximize esters production were established.
lipases; alcoholysis; biodiesel; castor bean oil
