Directed evolution of a maltogenic alpha-amylase from Bacillus sp. TS-25

Area of Science:

• Enzymology
• Protein Engineering
• Industrial Biotechnology

Background:

• Novamyl (maltogenic alpha-amylase) is used as an anti-staling agent in neutral pH baked goods.
• Wild-type Novamyl is inactivated at low pH, limiting its use in sourdough and rye breads.
• Improving enzyme stability at low pH is crucial for expanding its baking applications.

Purpose of the Study:

• To engineer Novamyl for enhanced thermal stability and activity at low pH.
• To broaden the industrial application of Novamyl in acidic bread formulations.
• To identify specific enzyme variants suitable for sourdough and rye bread production.

Main Methods:

• Directed evolution using error-prone PCR to generate mutant libraries.
• High-throughput screening of enzyme variants for improved low pH performance.
• DNA shuffling to iteratively recombine beneficial mutations and enhance enzyme properties.

Main Results:

• Several Novamyl variants exhibited over 10°C increased thermal stability at pH 4.5.
• One engineered variant demonstrated significant anti-staling effects in low pH breads.
• The directed evolution approach successfully identified improved maltogenic alpha-amylase enzymes.

Conclusions:

• Directed evolution is effective for improving enzyme functionality in specific industrial conditions.
• Enhanced Novamyl variants offer viable solutions for anti-staling in low pH baked goods.
• This research expands the potential of enzymes in food processing, particularly in acidic environments.