Engineering Corynebacterium glutamicum for efficient l-homoserine production.

Area of Science:

• Metabolic Engineering
• Synthetic Biology
• Biotechnology

Background:

• l-homoserine is a key precursor for essential amino acids and bio-based products.
• Current production yields of l-homoserine in Corynebacterium glutamicum are limited.
• Efficient microbial production is crucial for industrial applications in cosmetics, food, and pharmaceuticals.

Purpose of the Study:

• To engineer Corynebacterium glutamicum for enhanced l-homoserine production.
• To identify and modify key enzymes involved in l-homoserine biosynthesis.
• To optimize metabolic pathways for increased yield and productivity.

Main Methods:

• Strain optimization through gene knockout (thrB).
• Site-directed saturation mutagenesis of homoserine kinase (HK) to improve enzyme properties.
• Molecular docking to analyze enzyme-substrate interactions.
• Optimization of l-homoserine efflux mechanisms.
• Fermentation studies in shake flasks and a 15 L fermenter.

Main Results:

• Engineered strain HWZ006 achieved 20.8 g/L l-homoserine (0.231 g/g glucose).
• Mutant strain R240I (mutated HK) produced 26.8 g/L l-homoserine (0.298 g/g glucose).
• Final strain R240I/pXTuf-Cgl2344 reached 29.9 g/L (0.332 g/g glucose) in shake flasks.
• Fermentation in a 15 L fermenter yielded 78.3 g/L l-homoserine (0.28 g/g glucose).

Conclusions:

• Metabolic engineering strategies significantly enhanced l-homoserine production in C. glutamicum.
• Targeted modification of homoserine kinase and optimization of efflux pathways are effective.
• Achieved high-titer production demonstrates the potential for industrial-scale bio-production of l-homoserine.