基盘细胞具有底物消耗量低、繁殖速度快和代谢旺盛的特点。但并非基因组越小效果越好。构建基盘细胞 (包含基础物质、能量代谢基因、细胞结构、繁殖代谢基因和重要调控基因) 具有理论研究意义；解淀粉芽孢杆菌基盘细胞基因组的进一步优化是本研究的重要内容。本课题研究内容包括：①利用前期已构建好的敲除了9.85%冗余基因的小基因组菌株，通过监测生长与代谢特征和无痕基因敲除并行实验的方法，确立解淀粉芽孢杆菌LL3的最适基因组，构建底盘细胞；②对基盘细胞基因组进行进一步优化和改良，包括引入外源基因vgb、调整oriC位置等；③ 研究oriC (ori2、dnaA、ori1)和dnaN以及复制起始调控因子YabA在基因组复制中的功能；④构建出oriC和dnaN多拷贝菌株，最终获得优良基盘细胞；⑤在优良基盘细胞的基础上构建γ聚谷氨酸合成菌株，研究其生长特征和γ-聚谷氨酸合成。

The chassis cells possess many favorable features such as low substrate consumption, high propagation speed and vigorous metabolism. However, not the smaller genome strains exhibit the better features. The construction of chassis cell (including basic substance and energy metabolic genes and genes involved in cell construction, propagation and regulation) possesses important theoretical significance. The main content of this study is the further optimization of the chassis cell of Bacillus amyloliquefaciens strain. This project including the following aspects: ① construction of the chassis cell of the B. amyloliquefaciens based on our previously constructed genome reduced strain (with 9.85% of its redundant genes deleted) by monitoring the cell growth, metabolic characteristics and parallel gene deletion experiments on wild-type strain; ② the optimization and improvement of the chassis cell genome such as introducing heterologous vgb gene, relocation the oriC etc.; ③ exploring the functions of dnaN, oriC (ori2, dnaA and ori1) and the replication initiation factor YabA； ④ construction of the final excellent chassis cell with multiple copies of oriC and dnaN; ⑤ construction of the γ-PGA producing strain based on the excellent chassis cell and study its growth characteristics and γ-PGA synthesis.