Abstract

Succinic acid is an important platform and/or commodity or specialty chemical with a broad range of applications. The metabolic role of pyruvate formatelyase A (pflA) in relation to succinate production in Escherichia coli under anaerobic conditions from glucose substrate remained largely unspecified. Herein we identified pflAgene for the first time, as a novel gene knockout target for increasing succinate production in E. coli. Guided by E. coli reconstruction iJO1366, we engineered the E. coli host metabolism by deleting the pflA, thereby causing the up-regulation of glyceraldehyde- 3-phosphate dehydrogenase (GAPDH), which hypothetically increases the generation of NADH and the pool of phosphoenolpyruvate (PEP) in the central carbon metabolism, required for succinate production. This strategy produced succinic acid that is 4.78 fold (0.28g l-1 in 1day) from glucose substrate. This work elucidatesfor the first time that pflA is a novel gene deletion target for increasing succinic acid production in E. coli under anaerobic conditions. In addition, these results highlight the power of metabolic model in identifying novel gene deletion target and ultimately driving novel biological discovery.

Keywords: Escherichia coli genome-scale model;Metabolic gene knockout prediction;Pyruvate formatelyase (pflA); Glucose carbon source; Enhanced succinate production