生物法合成维生素C棕榈酸酯

Biological Synthesis of L-ascorbyl Palmitate

研究了不同的脂肪酶在有机溶剂体系中催化合成L维生素C棕榈酸酯的反应。针对维生素C在有机溶剂中溶解度较低这一问题,对催化合成维生素C棕榈酸酯反应的脂肪酶和反应介质进行比较,同时对影响合成维生素C棕榈酸酯反应的因素(温度、底物浓度、底物摩尔比、反应时间和酶量等)进行探讨,优化了反应条件:在10mL的丙酮中,1.094g棕榈酸与0.107g维生素C在酶量为20%(WW,固定化酶维生素C)的固定化脂肪酶催化下,初始含0.4nm分子筛20%,温度为60℃,转速为200rmin,反应48h转化率可以达到80%,产物维生素C棕榈酸酯的浓度可达20gL。

Biological synthesis of L-Ascorbyl Palmitate in organic system were studied in this text. The contradiction between conversion of vitamin C and concentration of L-Ascorbyl Palmitate were resolved. High conversion of vitamin C and concentration of L-Ascorbyl Palmitate were obtained by Novo435. A series of solvents（log P from -0.24 to 3.5 ）were investigated for the reaction, and acetone was found to be the most suitable from the standpoint of the enzyme activity and solubility of L-ascorbic. And the equilibrium of the reaction was affected by the addition of the molecular sieves and temperature. Reaction carried out at 60℃ and with 20% 0.4nm molecular sieves is good for the enzyme to keep its activity and for making the equilibrium go to the product. With 1.094g palmitic acid, 0. 107g vitamin C and 0.020g Novo435, rotate rate of 200r/min, the conversion of ascorbic reached 80% and the concentration of L-ascorbyl palmitate is 20g/L after 48h. Furthermore, reaction batch of Novo435 and substrates recycle were observed, the result indicated that Novo435 may used 4-5 times continuously with high conversion. And 6-O-unsaturated acyl L-ascorbates were synthesized through Novo435 condensation of ascorbic acid and various unsaturated fatty acids with high conversion in this text.