Synergistic effects of chromosomal ispB deletion and dxs overexpression on coenzyme Q10 production in recombinant Escherichia coli expressing Agrobacterium tumefaciens dps gene

For biotechnological production of coenzyme Q(10) (CoQ(10)) in recombinant Escherichia coli, three genetic manipulations were performed: heterologous expression of decaprenyl diphosphate synthase (Dps) from Agrobacterium tumefaciens, deletion of endogenous octaprenyl diphosphate synthase (IspB), and overexpression of 1-deoxy-D-xylulose synthase (Dxs). Expression of the dps gene and deletion of the ispB gene in E. coli BL21 (DE3)Delta ispB/pAP1 allowed production of CoQ(10) only. Furthermore, coexpression of the dxs gene increased the specific content of CoQ(10) from 0.55-0.89 mg g(-1) to 1.40 mg g(-1). For mass production of CoQ(10), fed-batch fermentation of E coli BL21 (DE3)Delta ispB/pAP1 + pDXS was carried out in a defined medium with 20 g l(-1) initial glucose and by the glucose-feeding strategy of pH-stat. Finally, 99.4 mg l(-1) CoQ(10) concentration, 1.41 mg g(-1) specific CoQ(10) content and 3.11 mg l(-1) h(-1) productivity were obtained in 33 h of the fermentation, which were 78,1.9, and 19 times higher than those for E. coli BL21 (DE3)/pAP1 without the ispB deletion and dxs overexpression. (C) 2009 Elsevier B.V. All rights reserved.