酶法合成右旋糖酐的研究

Enzymatic synthesis of dextran

利用肠膜状明串珠菌(Leuconstoc mesenteriodes)右旋糖酐蔗糖酶催化蔗糖合成右旋糖酐。分别探讨了不同蔗糖浓度、加酶量、反应温度、pH值和反应时间等因素对蔗糖转化率的影响,从中选取影响较显著的3个因素如蔗糖浓度、反应温度、pH值,采用均匀设计试验方法对酶促反应条件进一步优化,确定酶促反应最佳工艺参数。实验结果表明:酶法合成右旋糖酐的最佳条件为:蔗糖浓度50g/L,加酶量为0.214U,反应温度12℃,pH值为7.5,反应时间为30h,蔗糖转化率约为31%。

Dextran is synthesized by dextransucrase from Leuconostoc mesenteroides. Effects of sucrose concentrations, enzyme concentrations, temperature, pH and reaction time on transformation yield of sucrose were investigated. Three significant factors （i.e., sucrose, temperature and pH） were selected, and then uniform design method was used to optimize the condition of enzymatic reaction. The optimal conditions of dextran synthesis were as followed： sucrose 50g/L, enzyme 0.214U, temperature 12℃, pH 7.5 and reaction time 30h. Under these conditions, the dextran yield was about 31%.