Optimization of the production of biodiesel by a commercial immobilized lipase in a solvent-free system using a response surface methodology

Response surface methodology was used for the evaluation of the ef- fects of various factors on the synthesis of biodiesel catalyzed with immobi- lized lipase from Rhizomucor miehei in a solvent-free system. The production of biodiesel was optimized and model response equations were obtained, ena- bling the prediction of biodiesel production from the values of the four main factors. It would seem that the reaction temperature and the amount of water predominantly determined the conversion process while the methanol/oil molar ratio had no significant influence on the reaction rate. The temperature and amount of water showed negative interactive effects on the observed reaction rate per amount of enzyme. However, there were no significant interactions among the other variables according to the test of statistical significance. The highest yield of 10.15 mol kg-1 enzyme was observed at 45 °C with a 6:1 me- thanol to oil molar ratio and with no added water in the system.