Improved 2-methyl-1-propanol production in an engineered Bacillus subtilis by constructing inducible pathways

Area of Science:

• Metabolic Engineering
• Synthetic Biology
• Biotechnology

Background:

• High-level constitutive gene expression can lead to metabolic imbalance and reduced cellular production.
• Controlling gene expression is crucial for optimizing biosynthesis pathways.

Purpose of the Study:

• To engineer inducible gene expression systems in Bacillus subtilis for controlled biosynthesis of 2-methyl-1-propanol.
• To determine optimal induction conditions for maximizing 2-methyl-1-propanol production.

Main Methods:

• Construction of a P(alsSD)-controlled auto-inducible 2-ketoisovalerate pathway.
• Construction of a P(spac)-controlled IPTG-inducible Ehrlich pathway in Bacillus subtilis.
• Optimization of IPTG induction time and concentration for 2-methyl-1-propanol biosynthesis.

Main Results:

• Optimal IPTG induction was determined at 9.5 hours and 300 μM.
• The engineered strain BSUΔL-03 achieved a production of 3.83 ± 0.46 g/l of 2-methyl-1-propanol.
• This represents a 60% increase in production compared to strains with constitutive pathways.

Conclusions:

• Inducible gene expression systems effectively modulate metabolic pathways in Bacillus subtilis.
• Optimized inducible pathways significantly enhance 2-methyl-1-propanol biosynthesis, overcoming limitations of constitutive expression.