Multi-module engineering to guide the development of an efficient L-threonine-producing cell factory

Area of Science:

• Biotechnology
• Metabolic Engineering
• Synthetic Biology

Background:

• High-productivity microbial strains are essential for industrial bio-manufacturing.
• Escherichia coli is a key host for producing valuable chemicals.
• Efficient L-threonine production is critical for various industries.

Purpose of the Study:

• To develop a high-yield L-threonine producing strain of Escherichia coli.
• To implement multi-module metabolic engineering for rapid strain development.
• To enhance L-threonine production through CO2 capture and dynamic balancing.

Main Methods:

• Rational division of the L-threonine synthesis pathway into five modules.
• Optimization of gene expression within each module.
• Enhancement of CO2 capture and fixation.
• Dynamic balancing of cell growth and yield using a quorum-sensing system.

Main Results:

• Achieved rapid transition from zero-producer to hyperproducer of L-threonine.
• Accumulated 34.24 g/L L-threonine through module optimization and CO2 enhancement.
• Developed the THR36-L19 strain accumulating 120.1 g/L L-threonine with a yield of 0.425 g/g glucose in a 5 L bioreactor.
• Demonstrated the highest reported yield for de novo L-threonine production without inducers or antibiotics.

Conclusions:

• Multi-module metabolic engineering is effective for rapid development of hyperproducing strains.
• Enhanced CO2 fixation and dynamic metabolic balancing significantly improve L-threonine yield.
• The developed strain and methodology offer a robust platform for industrial bio-production of L-threonine and other chemicals.