[Auto-inducible expression system based on the SigB-dependent ohrB promoter in Bacillus subtilis]

Area of Science:

• Industrial Biotechnology
• Molecular Biology
• Microbial Engineering

Context:

• Reliable heterologous protein production is crucial for industrial biotechnology.
• Auto-inducible gene expression systems offer efficient protein production strategies.
• Bacillus subtilis is a well-established host for industrial protein expression.

Purpose:

• To develop and characterize a novel auto-inducible gene expression system in Bacillus subtilis.
• To utilize a SigB-dependent ohrB promoter for controlled gene expression.
• To produce xylanase as a model protein using high cell density cultivation.

Summary:

• A Bacillus subtilis expression plasmid with a SigB-dependent ohrB promoter was constructed.
• High cell density cultivation with an exponential fed-batch strategy was employed.
• A 6-fold increase in xylanase activity was observed due to SigB activation, confirming auto-inducibility and catabolite repression resistance.

Impact:

• The developed system provides a cost-effective and efficient tool for industrial biotechnology.
• It eliminates the need for expensive conventional inducers like isopropyl-β-galactopyranoside.
• This offers a promising alternative for recombinant protein production in microbial systems.