Creating Polyploid Escherichia Coli and Its Application in Efficient L-Threonine Production.

Area of Science:

• Synthetic Biology
• Microbial Engineering
• Genomics

Background:

• Prokaryotic genomes are typically haploid, limiting their potential in synthetic biology applications.
• Developing efficient microbial chassis is crucial for bio-based product manufacturing.
• Engineering polyploidy in prokaryotes offers a novel strategy to enhance cellular functions.

Purpose of the Study:

• To develop a method for constructing functional polyploid E. coli.
• To investigate the physiological and genetic characteristics of polyploid E. coli.
• To evaluate the application of polyploid E. coli in L-threonine production.

Main Methods:

• Regulation of the ftsZ gene to induce polyploidy in E. coli.
• Confirmation of polyploidy using PCR amplification, terminator localization, and flow cytometry.
• Transcriptome analysis to identify gene expression changes in polyploid cells.

Main Results:

• Successfully created artificial polyploid E. coli with 2-4 chromosomes.
• Polyploid E. coli exhibited larger cell size, enhanced low pH tolerance, and increased acetate resistance compared to haploid E. coli.
• Significant upregulation of key functional pathway genes was observed in polyploid E. coli.
• Achieved the highest reported L-threonine yield (160.3 g L⁻¹) in fed-batch fermentation using engineered polyploid E. coli.

Conclusions:

• An efficient method for constructing polyploid E. coli was established.
• Polyploid E. coli serves as a superior host strain for biochemical production, demonstrated by high L-threonine yield.
• This work provides a new avenue for studying prokaryotic evolution and chromosome function.