Engineering Escherichia coli for l-Threonine Hyperproduction Based on Multidimensional Optimization Strategies

Area of Science:

• Biotechnology
• Metabolic Engineering
• Synthetic Biology

Background:

• Biomanufacturing aims to enhance microbial strain productivity for chemical synthesis.
• Limited understanding of host metabolic networks hinders the identification of engineering targets.
• Optimizing l-threonine production requires addressing metabolic bottlenecks and global regulatory networks.

Purpose of the Study:

• To develop multidimensional engineering strategies for improving l-threonine production.
• To identify and engineer key metabolic and regulatory targets in high-yield strains.
• To achieve unprecedented l-threonine yield and productivity in a bioreactor setting.

Main Methods:

• Synergistic utilization of NADH and enhanced ATP supply to overcome metabolic bottlenecks.
• Regulation of citrate synthase (GltA) activity to redirect carbon flux into the TCA cycle.
• Transcriptomic analysis to identify the global stress response regulator UspA for enhancing production.

Main Results:

• Elimination of metabolic bottlenecks and redistribution of carbon flux significantly improved l-threonine synthesis.
• Identification and engineering of UspA enhanced host stress resistance and glucose utilization, further boosting productivity.
• Achieved a record l-threonine yield of 170.3 g/L and productivity of 3.78 g/L/h in a 5 L bioreactor.

Conclusions:

• Multidimensional metabolic and regulatory engineering strategies are effective for enhancing microbial production.
• The engineered THRH16 strain demonstrates superior l-threonine production capabilities.
• This study provides a framework for optimizing the production of other valuable chemicals through biomanufacturing.