Transesterification of used sunflower oil using immobilized enzyme

Transesterification reaction was performed using used sunflower oil and short-chain alcohol by immobilized lipase in non-aqueous conditions. The long-chain fatty acid alkyl ester, which is the product of this reaction, can be used as a diesel fuel that does not produce sulfur oxide and minimize the soot particulate. Immobilized enzymes Lipozyme RM IM and Novozyme 435 were screened. Lipozyme RM IM showed the highest activity in this reaction with mild reaction temperature of 45 °C. In solvent free system, there is inactivation of enzyme by methanol and glycerol. Hence, tertiary butanol is found to be a good solvent which solubilizes both triglycerides and glycerol. The activity of immobilized lipase was highly increased in comparison with solvent free system because its activity sites became more effective. Immobilized enzyme could be repeatedly used without troublesome method of separation and the decrease in its activity was not largely observed.