Development of a strong intracellular expression system for Bacillus subtilis by optimizing promoter elements

Area of Science:

• Microbiology
• Molecular Biology
• Biotechnology

Background:

• Transcription efficiency of inducible promoters is crucial for recombinant protein production.
• Current inducible promoter systems in Bacillus subtilis face limitations.
• Optimizing promoter regions can enhance gene expression levels.

Purpose of the Study:

• To engineer strong isopropyl-beta-D-thiogalactopyranoside (IPTG)-inducible promoters in Bacillus subtilis.
• To identify key nucleotide sequences for enhancing promoter strength.
• To improve recombinant protein yields in microbial cell factories.

Main Methods:

• Systematic nucleotide optimization of conserved regions within the groESL promoter.
• Targeted modifications in the UP element, -35, -15, -10, and +1 regions.
• Quantification of intracellular recombinant protein accumulation via analytical methods.

Main Results:

• Engineered groESL promoter variants demonstrated significantly enhanced transcription efficiency.
• Combined nucleotide optimizations led to a substantial increase in recombinant protein levels.
• Recombinant proteins accumulated intracellularly up to approximately 30% of total cellular protein.

Conclusions:

• Nucleotide optimization of the groESL promoter is an effective strategy to generate strong inducible promoters.
• This approach significantly enhances recombinant protein production in Bacillus subtilis.
• The developed promoters offer a valuable tool for industrial biotechnology applications.