Rational synthesis of 1,3-diolein by enzymatic esterification.

t-Butanol was an excellent reaction medium for enzyme-mediated esterification of oleic acid with glycerol for 1,3-diolein preparation which has been proved by our group. Herein, to achieve the rational synthesis of 1,3-diolien, response surface methodology was applied to examine the effects of the significant variables and their reciprocal effects on the product synthesis. Under the optimal conditions (62.4°C, 0.75g Novozym 435, substrate molar ratio (oleic acid/glycerol) 2.4 and 4.8g t-butanol), the diolein yield of 87.4% could be achieved, and the value of 1,3-diolien/diolein was as high as 87.8%, which were quite close to the predicted values. Compared with the results of our previous single factor experiment, although the values of diolein yield and 1,3-diolien/diolein could not be improved markedly, the enzyme dosage and the reaction medium were spared by 25% and 20%, respectively, which was a remarkable improvement of the enzymatic process.