High-level co-production of 3-hydroxypropionic acid and 1,3-propanediol from glycerol: Metabolic engineering and...

Area of Science:

• Biotechnology
• Metabolic Engineering
• Industrial Microbiology

Background:

• 3-Hydroxypropionic acid (3-HP) and 1,3-propanediol (1,3-PDO) are high-value chemicals with broad industrial applications.
• Sustainable production is hindered by inefficient microbial strains and fermentation processes.

Purpose of the Study:

• To enhance the co-production of 3-HP and 1,3-PDO using metabolically engineered Escherichia coli.
• To optimize fermentation strategies for increased yield and efficiency.

Main Methods:

• Metabolic engineering of E. coli to co-express 3-HP and 1,3-PDO biosynthetic pathways.
• Integration with transhydrogenase-mediated cofactor regeneration systems.
• Pathway rebalancing, byproduct formation blocking, and glycerol utilization pathway optimization.
• Two-stage pH-controlled fed-batch fermentation.

Main Results:

• Successfully engineered E. coli strains for simultaneous 3-HP and 1,3-PDO synthesis.
• Improved cofactor availability and product synthesis through pathway coupling.
• Significant increase in net titer of 3-HP and 1,3-PDO by pathway rebalancing and byproduct reduction.
• Maximized glycerol flux towards target metabolites.
• Achieved a combined titer of 140.50 g/L for 3-HP and 1,3-PDO with a 0.85 mol/mol net yield.

Conclusions:

• Metabolic engineering and fermentation optimization are effective strategies for high-yield co-production of 3-HP and 1,3-PDO.
• The developed process offers a sustainable route for producing these key industrial chemicals.