화학공학소재연구정보센터
Chinese Journal of Chemical Engineering, Vol.22, No.5, 559-569, 2014
Chromosomal Engineering of Escherichia coli for Efficient Production of Coenzyme Q(10)
The plasmid-expression system is routinely plagued by potential plasmid instability. Chromosomal integration is one powerful approach to overcome the problem. Herein we report a plasmid-free hyper-producer E. coli strain for coenzyme Q(10) production. A series of integration expression vectors, pxKC3T5b and pxKT5b, were constructed for chemically inducible chromosomal evolution (multiple copy integration) and replicon-free and markerless chromosomal integration (single copy integration), respectively. A coenzyme Q(10) hyper-producer Escherichia coli TBW20134 was constructed by applying chemically inducible chromosomal evolution, replicon-free and markerless chromosomal integration as well as deletion of menaquinone biosynthetic pathway. The engineered E. coli TBW20134 produced 10.7 mg per gram of dry cell mass (DCM) of coenzyme Q(10) when supplemented with 0.075 g . L-1 of 4-hydroxy benzoic acid; this yield is unprecedented in E. coli and close to that of the commercial producer Agrobacterium tumefaciens. With this strain, the coenzyme Q(10) production capacity was very stable after 30 sequential transfers and no antibiotics were required during the fermentation process. The strategy presented may be useful as a general approach for construction of stable production strains synthesizing natural products where various copy numbers for different genes are concerned.