Lv Xin, Dai Lu, Bai Fangmin, Wang Zhanqing, Zhang Liaoyuan, Shen Yaling
State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing Technology, East China University of Science and Technology, Shanghai, 200237 China.
Key Laboratory of Biopesticide and Chemical Biology, Ministry of Education, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002 Fujian China.
Bioresour Bioprocess. 2016;3(1):52. doi: 10.1186/s40643-016-0128-2. Epub 2016 Nov 28.
Optically pure acetoin (AC) is an important platform chemical which has been widely used to synthesize novel optically active α-hydroxyketone derivatives and liquid crystal composites.
In this study, C and A encoding -2,3-butanediol dehydrogenase (-2,3-BDH) and glycerol dehydrogenase (GDH), respectively, in MG1 were knocked out to block the conversion from AC to 2,3-butanediol (2,3-BD). The resulting strain MG14 was found to produce a large amount of optically pure ()-AC with a little 2,3-BD, indicating that another enzyme responsible for 2,3-BD formation except -2,3-BDH and GDH existed in the strain MG1. Furthermore, SlaR protein, a transcriptional activator of AC cluster, was overexpressed using promoter in the strain MG14, leading to enhancement of the ()-AC yield by 29.91%. The recombinant strain with overexpression of SlaR, designated as MG15, was used to perform medium optimization for improving ()-AC production.
Under the optimized conditions, 39.91 ± 1.35 g/l ()-AC was produced by strain MG15 with the productivity of 1.11 g/l h and the conversion rate of 80.13%.
光学纯乙偶姻（AC）是一种重要的平台化合物，已被广泛用于合成新型光学活性α-羟基酮衍生物和液晶复合材料。
在本研究中，敲除了MG1中分别编码-2,3-丁二醇脱氢酶（-2,3-BDH）和甘油脱氢酶（GDH）的C和A，以阻断从AC到2,3-丁二醇（2,3-BD）的转化。发现所得菌株MG14产生大量光学纯的（）-AC和少量2,3-BD，这表明菌株MG1中存在除-2,3-BDH和GDH之外的另一种负责2,3-BD形成的酶。此外，使用启动子在菌株MG14中过表达AC簇的转录激活因子SlaR蛋白，导致（）-AC产量提高29.91%。将过表达SlaR的重组菌株命名为MG15，用于进行培养基优化以提高（）-AC的产量。
在优化条件下，菌株MG15生产了39.91±1.35 g/l的（）-AC，生产率为1.11 g/l h，转化率为80.13%。
