全局转录因子σ定向进化提高肺炎克雷伯氏菌发酵木糖生产2,3-丁二醇能力的研究及其调控机理

2,3-丁二醇是一种高附加值的平台化合物和液体燃料。肺炎克雷伯氏菌（K. pneumoniae）五碳糖利用性能优良，在木糖生物转化方面极具开发潜力，但其木糖耐受力较低、对2,3-丁二醇转化效率不高，阻碍了其工业化应用。本项目拟通过细胞全局转录因子定向进化的方法获得稳定的高木糖耐受和高产2,3-丁二醇的菌株表型，为K. pneumoniae菌种的改良和构建工作奠定基础。同时通过转录组学分析，阐明突变株耐性提高和高产2,3-丁二醇的分子机制。本课题的开展将提高肺炎克雷伯氏菌木糖发酵生产2,3-丁二醇效率，解决木糖利用难题，具有重要的经济、社会和环境效益。同时也将扩展了定向进化技术在生物技术领域的应用, 使工业微生物菌种改造从经典的物理或化学随机突变向对特定启动子的定向进化和细胞整体代谢网络的操纵转变, 快速高效地提高菌种的耐受性和生产性能。

2, 3-butanediol is a kind of high value-added chemicals and liquid fuel. With good properties in pentose fermentation, K. pneumoniae has a great potential for xylose biotransformation. However, its industrial application is considerably hindered by shortcomings such as poor lactose tolerance. This project intends to improve K. pneumoniae strains with high xylose tolerance and high yield of 2, 3-butanediol phenotype, illustrate the molecular mechanism of phenotype mutation through the transcriptome analysis. The conduction of this subject will improve the fermentation production efficiency of 2, 3 - butanediol by K. pneumoniae and resolve the problem of xylose utilization, which has important economic, social and environmental benefits. This subject will also extend application of directed evolution in the field of biotechnology, make the transformation technology of microbial industrial strains changing from random mutations by using classic physics or chemistry method into directed evolution of specific promoter and cell metabolism network control. The new method used in this project can efficiently improve the xylose tolerance and 2,3-butanediol production performance.