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Abstract

The targeted increase of cellular adenosine triphosphate (ATP) turnover
(enforced ATP wasting) has recently been recognized as a promising tool
for metabolic engineering when product synthesis is coupled with net ATP
formation. The goal of the present study is to further examine and to
further develop the concept of enforced ATP wasting and to broaden its
scope for potential applications. In particular, considering the
fermentation products synthesized by Escherichia coli under anaerobic
conditions as a proxy for target chemical(s), i) a new genetic module
for dynamic and gradual induction of the F-1-part of the ATPase is
developed and it is found that ii) induction of the ATPase leads to
higher metabolic activity and increased product formation in E. coli
under anaerobic conditions, and that iii) ATP wasting significantly
increases substrate uptake and productivity of growth-arrested cells,
which is vital for its use in two-stage processes. To the best of the
authors' knowledge, the glucose uptake rate of 6.49 mmol gCDW(-1) h(-1)
achieved with enforced ATP wasting is the highest value reported for
nongrowing E. coli cells. In summary, this study shows that enforced ATP
wasting can be used to improve yield and titer (in growth-coupled
processes) as well as volumetric productivity (in two-stage processes)
depending on which of the performance measures is more crucial for the
process and product of interest.