重组Athrobacter ramosus S34MTSase和MTHase的酶学性质及其制备海藻糖的应用条件优化

摘要

以淀粉为底物,通过麦芽寡糖基海藻糖合成酶(maltosyhrehalose synthase,MTSase)和麦芽寡糖基海藻糖水解酶(mahosyltrehalose hydrolase,MTHase)的共同作用生产海藻糖是一种经济高效的方法.对Arthrobacter ramosus S34来源并分别在E.coli BL21(DE3)中表达的MTSase和MTHase的酶学性质进行研究,发现MTSase的最适温度为45℃,最适pH为7.0,MTHase的最适温度为55℃,最适pH为6.0.随后用2种酶共同作用生产海藻糖,优化反应条件,考查反应温度、初始pH、底物DE值、加酶量以及底物浓度等因素对酶转化过程中海藻糖产率的影响.最佳酶转化条件为反应温度45℃、初始pH5.5,底物DE值8.5,加酶量分别为MTSase最小加量15.75 U/g淀粉,MTHase最小加量7.5 U/g淀粉.%The production of trehalose from starch is an effective method under the combined action of maltosyltrehalose synthase (MTSase) and maltosyltrehalose hydrolase (MTHase).The optimum temperature of MTSase was 45℃,the optimal pH was 7.0,and the optimal temperature of MTHase was 55℃,the optimum pH was 6.0.Then trehalose was produced by the two enzymes together,and the reaction conditions were optimized.The effects of reaction temperature,initial pH,substrate DE value,enzymes amounts and substrate concentration on trehalose yield were investigated.The optimal conditions were as follows:the reaction temperature was 45 ℃,the initial pH was 8.5,the substrate DE value was 8.5 and the amount of MTSase and MTHase was 15.75 U/g and 7.5 U/g,respectively.