Engineering central metabolic modules of Escherichia coli for improving β-carotene production

ATP and NADPH are two important cofactors for production of terpenoids compounds. Here we have constructed and optimized beta-carotene synthetic pathway in Escherichia coli, followed by engineering central metabolic modules to increase ATP and NADPH supplies for improving beta-carotene production. The whole beta-carotene synthetic pathway was divided into five modules. Engineering MEP module resulted in 3.5-fold increase of beta-carotene yield, while engineering beta-carotene synthesis module resulted in another 3.4-fold increase. The best beta-carotene yield increased 21%, 17% and 39% after modulating single gene of ATP synthesis, pentose phosphate and TCA modules, respectively. Combined engineering of TCA and PPP modules had a synergistic effect on improving beta-carotene yield, leading to 64% increase of beta-carotene yield over a high producing parental strain. Fed-batch fermentation of the best strain CAR005 was performed, which produced 2.1 g/L beta-carotene with a yield of 60 mg/g DCW. (C) 2013 Elsevier Inc. All rights reserved.