Biosynthesis of oleyl oleate in solvent-free system by Candida rugosa Lipase (CRL) immobilized in macroporous resin with cross-linking of aldehyde-dextran

In our study, oleyl oleate was synthesized through enzymatic esterification of oleic acid with oleyl alcohol using Candida rugosa lipase (CRL) immobilized on macroporous resin in a solvent-free system. CRL was immobilized flexibly on the support via aldehyde-dextran, and the effectiveness of aldehyde-dextrans, as cross-linking agents with different molecular weights, was compared and discussed. The impact of various factors, such as different molecular weights of dextran, molar ratio between oleic acid and oleyl alcohol, and the temperature and stability of enzymes, on esterification was investigated as well. Our study indicated that lipase immobilized by 20000 Da dextran yielded the best result. The optimal condition to produce oleyl oleate using immobilized CRL was found in our study and turned out to be molar ratio of 1, reaction temperature of 40 °C, and a 12-h reaction time to reach reaction equilibrium. Under the optimal reaction conditions, a high percentage yield of ester was achieved (92.6%). The immobilized CRL also reached a conversion rate of 86.7% with excellent stability even after 8 cycles.