高效启动子在微生物生产4-羟基丁酸中的应用

4-羟基丁酸(4HB)是一种精神类药物,还可用于合成聚-4-羟基丁酸酯(P4HB)、聚(3-羟基丁酸酯-co-4-羟基丁酸酯)(P3HB4HB)等聚合物。在醇脱氢酶(DhaT)和醛脱氢酶(AldD)的共同作用下,1,4-丁二醇(BD)可转化为4-羟基丁酸。通过引入T7和PRe两种高效启动子,加强了dhaT和aldD基因的表达,促进合成4-羟基丁酸的反应进行。同时还研究了底物1,4-丁二醇的浓度对4HB生产的影响。结果表明:提供10 g/L的1,4-丁二醇,受PRe启动子调控的重组菌A.hydrophila 4AK4(pZQ01)可生产6.00 g/L的4-羟基丁酸,比对照组提高43.20%;而受T7启动子调控的重组菌A.hydrophila 4AK4(pZQ04)可生产4.87 g/L 4-羟基丁酸,比对照组提高16.23%。意味着T7和PRe这两种启动子确实发挥了提高基因表达水平的作用,加速了4-羟基丁酸的生物合成。

Application of high efficiency promoters in microbial production of 4-hydroxybutyric acid

4-hydroxybutyric acid (4HB) is a psychotropic drug used for polymer synthesis such as poly (4-hydroxybutyric acid) (P4HB) and poly (3-hydroxybutyric acid-co-4-hydroxybutyric acid) (P3HB-co-4HB). 1,4-butanediol (BD) can be converted to 4-hydroxybutyric acid by alcohol dehydrogenase (DhaT) and aldehyde dehydrogenase (AldD). In this study, high efficiency promoters including T7 promoter and PRe promoter were cloned to increase expression of dhaT and aldD, and thus accelerate the conversion from BD to 4HB. A. hydrophila 4AK4 (pZQ01), the recombinant strain under the control of T7 promoter, produced 6.00 g/L 4HB from 10 g/L BD with the productivity increased by 43.20%. While A. hydrophila 4AK4 (pZQ04), the strain under the control of T7 promoter, produced 4.87 g/L 4HB from 10 g/L BD, and the productivity was increased by 16.23%. Thus, the gene expression was increased by T7 and PRe promoters, leading to an accelerated biosynthesis of 4HB.