The effect of fatty acid concentration and water content on the production of biodiesel by lipase

The kinetics of the production of biodiesel by esterification of butyric acid with methanol, catalysed by lipase from Mucor miehei, was studied in two types of systems, namely, n-hexane microaqueous and biphasic (n-hexane/water) containing different amounts of water. The experimental results were fit to a Ping-Pong mechanism and the constants found in the rate expression were determined. The results have shown that in a microaqueous media, butyric acid does not inhibit the reaction in the range of initial concentrations considered. The effect of water content on the initial rate of reaction and conversion were illustrated. It was shown that the initial rate of reaction increased as the initial water content increased up to 25% (v/v). However, the conversion was found to be higher at low initial water concentrations.