Diao Mengxue, Chen Xianrui, Li Jing, Shi Ya'nan, Yu Bo, Ma Zhilin, Li Jianxiu, Xie Nengzhong
State Key Laboratory of Non-Food Biomass and Enzyme Technology, National Engineering Research Center for Non-Food Biorefinery, Guangxi Biomass Engineering Technology Research Center, Guangxi Academy of Sciences, 98 Daling Road, Nanning 530007, China.
State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Life Science and Technology College, Guangxi University, Nanning 530004, China.
Microorganisms. 2023 Jan 13;11(1):203. doi: 10.3390/microorganisms11010203.
Acetoin is an important four-carbon platform chemical with versatile applications. Optically pure ()-acetoin is more valuable than the racemate as it can be applied in the asymmetric synthesis of optically active α-hydroxy ketone derivatives, pharmaceuticals, and liquid crystal composites. As a cytotoxic solvent, acetoin at high concentrations severely limits culture performance and impedes the acetoin yield of cell factories. In this study, putative genes that may improve the resistance to acetoin for were screened. To obtain a high-producing strain, the identified acetoin-resistance gene was overexpressed, and the synthetic pathway of ()-acetoin was strengthened by optimizing the copy number of the key genes. The engineered . strain GXASR-49RSF produced 81.62 g/L ()-acetoin with an enantiomeric purity of 96.5% in the fed-batch fermentation using non-food raw materials in a 3-L fermenter. Combining the systematic approach developed in this study with the use of low-cost feedstock showed great potential for ()-acetoin production via this cost-effective biotechnological process.
乙偶姻是一种重要的四碳平台化合物，具有广泛的应用。光学纯的（）-乙偶姻比外消旋体更有价值，因为它可用于光学活性α-羟基酮衍生物、药物和液晶复合材料的不对称合成。作为一种细胞毒性溶剂，高浓度的乙偶姻会严重限制培养性能，并阻碍细胞工厂的乙偶姻产量。在本研究中，筛选了可能提高对乙偶姻抗性的假定基因。为了获得高产菌株，对鉴定出的乙偶姻抗性基因进行了过表达，并通过优化关键基因的拷贝数来强化（）-乙偶姻的合成途径。工程菌株GXASR-49RSF在3-L发酵罐中使用非食品原料进行补料分批发酵时，产生了81.62 g/L的（）-乙偶姻，对映体纯度为96.5%。将本研究中开发的系统方法与使用低成本原料相结合，显示出通过这种具有成本效益的生物技术过程生产（）-乙偶姻的巨大潜力。
