Characterization of an Entner-Doudoroff pathway-activated Escherichia coli

Area of Science:

• Microbiology
• Metabolic Engineering
• Synthetic Biology

Background:

• Escherichia coli possesses both Embden-Meyerhof-Parnas (EMPP) and Entner-Doudoroff (EDP) pathways for glucose breakdown.
• The EDP is typically inactive during glucose metabolism but offers advantages over EMPP for specific product synthesis.

Purpose of the Study:

• To activate the latent Entner-Doudoroff pathway (EDP) in E. coli for enhanced glucose metabolism.
• To engineer E. coli strains for improved bio-conversion of cellulosic biomass and production of target compounds.

Main Methods:

• Gene deletion of pfkAB to initiate EDP activation.
• Adaptive Laboratory Evolution (ALE) to select for functional EDP.
• Genotypic, transcriptomic, and phenotypic analyses to understand metabolic shifts.
• Strain engineering for enhanced production of lycopene and 3-hydroxypropionic acid.

Main Results:

• Successful activation of the EDP pathway in E. coli through gene deletion and ALE.
• Identification of key mutations in regulatory and glycolytic genes (crp, galR, gntR, gnd, ptsG, talB) that enhance EDP function.
• Demonstrated improved cellulosic biomass bio-conversion.
• Engineered strains achieved higher yields of lycopene and 3-hydroxypropionic acid.

Conclusions:

• E. coli possesses an inherent capability to utilize EDP for glucose metabolism, complementing the EMPP.
• The study highlights the potential of harnessing EDP for biotechnological applications.
• Engineered E. coli strains demonstrate enhanced metabolic versatility for producing valuable chemicals.