作　　者： ; ;

机构地区： 南京农业大学食品科技学院

出　　处： 《催化学报》 2007年第4期339-344,共6页

摘　　要： 研究了在有机介质叔丁醇中魔芋葡甘聚糖(KGM)的分子量及酰基供体对固定化脂肪酶Novozym 435催化KGM乙酰化反应的影响.KGM的分子量对酶促其酰化反应的活性及产物取代度有显著影响.随着KGM分子量的增大,酶催化反应的速率逐渐下降,产物的取代度逐渐减小.KGM分子量对该反应的影响与不同分子量KGM的溶解度、体系粘度、空间位阻及颗粒形态等因素有关.以不同链长的脂肪酸乙烯酯为酰基供体时,随着酰基供体中脂肪酸碳链的增长,酶促KGM酰化反应速率逐渐下降,产物的取代度逐渐减小,且该酰化反应具有高度的区域选择性,反应均发生在C6-OH上. The effects of weight-average molecular mass （Mw） of konjac glucomannan （KGM） and acyl donors on its acylation catalyzed by an immobilized lipase Novozym 435 in t-BuOH were investigated. The results demonstrated that the Mw of KGM had a significant effect on the acylation. The initial reaction rate and degree of substitution of the product decreased with the increase in Mw of KGM. These could be related to the difference in solubility of KGM, viscosity of the reaction system, steric hindrance, and granule structure of KGM with different Mw values. When fatty acid vinyl esters were used as acyl donors for the Novozym 435-catalyzed acylation of KGM in t-BuOH, the initial reaction rate and substitution degree of the product decreased with increasing carbon-chain length of fatty acid vinyl esters. Novozym 435-catalyzed acylation of KGM with various acvl donors in t-BuOH was highly regioselective and occurred predominantly at the C6-OH group of KGM.

关 键 词： 魔芋葡甘聚糖 酰化反应 区域选择性 脂肪酶 分子量 酰基供体

领　　域： [理学] [理学] [生物学]