Biofuel production from castor oil with immobilized lipase

Using as catalyst a immobilized lipase Muchor miehi and a solvent additive, castor oil enzymatic transesterification with methanol was analyzed. In order to evaluate the process and the chemical reaction conditions, a statistical experiment design was applied by varying the catalyst and additive concentrations. Since viscosity and acidity index have a strong effect on bio-diesel characteristics from castor oil, these parameters were taken as the comparative response variables. It was found that the best operation condition occurred when a weight concentration of enzymes was near 13% and additive volume concentration was near 30%. With these conditions, the viscosity had values close to 59 mm(2)/s and the acidity had values of 6 mg NaOH by gram of sample. Within the range of the most appropriate conditions, methyl esters were characterized during the reaction. The fastest conversion reaction took place in the first four hours (more than 30% w/w of methyl esters in the products), then this velocity decreased progressively until it obtained a concentration of methyl esters higher than 45% at approximately seven hours.