A novel strategy to finely control the electron transfer chain (ETC) activity of Escherichia coli was established. In this study, the fine-tuning of the ubiquinone biosynthesis pathway was applied to further controlling ETC function in coenzyme Q8 biosynthesis-deficient E. coli strains, HW108 and HW109, which contain mutations in ubiE and ubiG, respectively. A competing pathway on the intermediate substrates of the Q8 synthesis pathway, catalyzed by diphosphate:4-hydroxybenzoate geranyltransferase (PGT-1) of Lithospermum erythrorhizon, was introduced into these mutant strains. A nearly theoretical yield of lactate production can be achieved under fully aerobic conditions via an in vivo, genetically fine-tunable means to further control the activity of the ETC of the Q8 biosynthesis-deficient E. coli strains.
Keywords: Escherichia coli; electron transfer chain; lactate; metabolic controlling; ubiquinone.
© 2015 Wiley Periodicals, Inc.