Efficient biosynthesis of 3-hydroxypropionic acid from ethanol in metabolically engineered Escherichia coli

Area of Science:

• Biotechnology and metabolic engineering for sustainable chemical production.
• Microbial cell factory development for carbon-neutral synthesis.
• Biorefinery advancements utilizing CO2-based feedstocks.

Background:

• Engineered acetogens produce ethanol from syngas, a key intermediate for biorefineries.
• 3-hydroxypropionic acid (3-HP) is a crucial building block chemical with diverse applications.
• The malonyl-CoA pathway offers a route for synthesizing 3-HP from ethanol with CO2 fixation.

Purpose of the Study:

• To investigate the impact of different ethanol consumption pathways on 3-HP synthesis.
• To evaluate the role of the TCA cycle, gluconeogenesis, and transhydrogenase in 3-HP production.
• To optimize the 3-HP synthesis pathway in engineered microbial hosts.

Main Methods:

• Metabolic engineering of microbial strains for enhanced 3-HP production from ethanol.
• Investigation of key metabolic pathways including ethanol consumption, CO2 fixation, and 3-HP synthesis.
• Optimization of the 3-HP biosynthetic pathway and whole-cell biocatalysis.

Main Results:

• Engineered strain achieved 1.66 g/L of 3-HP with a yield of 0.24 g/g.
• Whole-cell biocatalysis significantly enhanced 3-HP production to 13.17 g/L with a yield of 0.57 g/g.
• Demonstrated the feasibility of utilizing ethanol as a feedstock for 3-HP synthesis.

Conclusions:

• Ethanol is a viable feedstock for the production of 3-hydroxypropionic acid via engineered microbial pathways.
• Optimization of metabolic pathways and whole-cell biocatalysis can substantially improve 3-HP titer and yield.
• This research provides a promising alternative route for 3-HP production in future biorefineries.