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

Enzymatic properties of recombinant Athrobacter ramosus S34 MTSase and MTHase and optimization of application conditions for production of trehalose

以淀粉为底物,通过麦芽寡糖基海藻糖合成酶(maltosyltrehalose synthase,MTSase)和麦芽寡糖基海藻糖水解酶(maltosyltrehalose 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 mahosyl- trehalose synthase （MTSase） and mahosyltrehalose 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 reac- tion 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.