Effect of different biochemical parameters on the enzymatic synthesis of fructose oleate

Enzymatic synthesis of sugar ester was performed using an immobilized Candida antartica lipase, fructose and oleic acid methyl ester as substrates and 2-methyl 2-butanol as a solvent. The influence of the molar ratio sugar/acyl donor, methanol concentration and temperature on the performance of the transesterification reaction were studied. When the molar ratio was adjusted only at the beginning of the reaction, the highest concentration of fructose oleate (16 g l(-1)) was obtained at a ratio of 1:5. When this ratio was kept constant throughout the duration of the reaction (by adding an excess of fructose or by continuous methyl-oleate feeding), 34 g l(-1) and 39 g l(-1), respectively, of fructose oleate were obtained at a molar ratio of about 1:8. The influence of methanol, which was a byproduct of the reaction, was also investigated. Results indicated that this compound was a strong inhibitor of Candida antartica lipase activity. The increase of temperature from 60 to 80 degrees C led to an increase of sugar ester concentration. However, the stability of the enzyme decreased as the temperature rose. At 80 degrees C, more than 90% of the initial activity was lost while at 60 degrees C, at the same time, only 30% was lost.