一株联产L-精氨酸和聚羟基丁酸酯的重组钝齿棒杆菌的构建

Co-Production of L-Arginine and Polyhydroxybutyrate in Recombinant Corynebacterium crenatum

摘要:

Corynebacterium crenatum SYPA 5-5是一株用于L-精氨酸（Arg）生产的工业菌株。聚羟基丁酸酯（PHB）是在细菌内部形成的聚合物，将PHB代谢途径引入细胞内可影响胞内的全局代谢网络，实现联产PHB和相关化工产品如琥珀酸、L-谷氨酸和L?鄄色氨酸等。采用基因工程技术，将来源于Ralstonia eutropha H16的PHB合成基因簇phbCAB导入到L-精氨酸生产菌株C. crenatum SYPA 5-5中，进行组成型表达，旨在获胞内产PHB、胞外产L-精氨酸的效果，对出发菌和重组菌分别进行5 L容积发酵罐实验，并对发酵相关参数进行测定分析。结果表明，由于PHB合成基因簇的导入，重组菌中PHB质量为细胞干质量的12.8%，实现了胞外产L?鄄精氨酸、胞内产PHB的效果，并发现胞内PHB的积累对菌体生产L-精氨酸有一定的正向作用，发酵96 h，L-精氨酸的产量达到43.21 g/L，相比于出发菌提高了20%。

Abstract:

Corynebacterium crenatum SYPA 5-5 is a industrial strain for L-arginine production. Polyhydroxybutyrate （PHB）is a kind of polymer stored in the bacterial as carbon source and energy. Due to its environment-friendly properties such as biodegradability and biocompatibility，PHB can be made into plastic containers and surgical suture to reduce the white pollution and can be digested easily in the body. It was reported that co-producing PHB and some other industrial valuable compounds，such as succinate，L-glutamate and tryptophan，were possible by introducing PHB metabolic pathways into the cells to influence the intracellular pathways. In this study，a co-produce PHB and L-arginine strain was constructed by introducing the entire phbCAB operon of Ralstonia eutropha H16 into C. crenatum SYPA 5-5. Fermentation were conducted of the start strain and recombinant one，separately，in a 5-L fermentor and relevant fermentation parameters were detected and analysed. The result showed that intracellular PHB（12.8% of DCW） and extracellular L-arginine （43.21 g/L） were obtained and accumulated in the recombinant strain，.In addition，The PHB production also promote the L-arginine yield，which weas increased by 20%.