High-Level Expression of Sucrose Isomerase in Bacillus subtilis Through Expression Element Optimization and...

Area of Science:

• Biotechnology
• Enzyme Engineering
• Food Science

Background:

• Sucrose isomerase is crucial for producing isomaltulose, a functional sugar.
• Current production levels in safe hosts are insufficient for industrial demand.

Purpose of the Study:

• To significantly improve sucrose isomerase expression in Bacillus subtilis.
• To optimize recombinant protein production for industrial applications.

Main Methods:

• Overexpression of extracellular chaperone PrsA to enhance protein folding.
• Promoter screening to optimize protein synthesis levels.
• Optimization of fermentation conditions (nitrogen/carbon sources, metal ions, pH, temperature) in shake-flask and bioreactor.

Main Results:

• Recombinant expression increased by 80.02% with PrsA overexpression.
• Promoter screening yielded a further 60.40% increase in expression.
• Optimized bioreactor cultivation achieved a record 862.86 U/mL sucrose isomerase activity in food-safe strains.

Conclusions:

• Combined strategies of expression element and fermentation optimization effectively enhance food enzyme production in B. subtilis.
• Achieved highest reported sucrose isomerase activity in food-safe strains.
• Provides a viable strategy for industrial-scale enzyme production.