【摘要】 目前L-苹果酸已经工业化生产,但仍存在苹果酸产生菌株来源有限和产量不高等问题,为了拓展苹果酸产生菌的种类及酶活性,通过基因工程手段分别利用p ETDuet-1为载体在宿主细胞Escherichia coli BL21（DE3）中重组表达了谷氨酸棒状杆菌（Corynebacterium glutamicum）和大肠杆菌（E.coli）来源的富马酸酶,并对两者的酶学性质以及催化效率进行了比较。结果表明:两种来源的富马酸酶均构建成功,谷氨酸棒状杆菌来源的富马酸酶（fum Cc）最适温度和p H分别为30℃和8.0,大肠杆菌来源的富马酸酶（fum Ce）最适温度和p H分别为40℃和7.0;酶动力学分析表明,fum Cc酶催化效率(K_cat/K_m)是fum Ce的3.8倍。0.1 g菌体细胞在10 m L转化体系中催化1.5 g富马酸钠,在各自的最适条件下反应6 h,L-苹果酸的产率分别为85%和34%。更多还原

【Abstract】 Although industrialized, the production of L-malic acid still suffered from problems such as limited sources of producing strains and low yield. In order to exploit malic acid producing strains and improve enzyme activities, genes encoding fumarase from Corynebacterium glutamicum（fum Cc） and Escherichia coli（fum Ce） were expressed in E. coli BL21（DE3） using p ETDuet-1 as vector. The enzymatic properties and catalytic efficiency of fum Cc and fum Ce were investigated. The results showed that the optimal temperature and p H for fum Cc were 30 ℃ and8.0, while those for fum Ce were 40 ℃ and 7.0. The kinetic analysis showed that the catalytic efficiency(K_cat/K_m) of fum Cc was 3.8 times higher than that of fum Ce. Under optimum conditions,biotransformations of disodium fumarate（150 g/L） using wet cells expressing fum Cc or fum Ce（10g/L）, resulted in L-malic acid yields of 85% and 34%, respectively.更多还原