Recurrent mutation and selection for increased penicillin titre in Aspergillus nidulans

Area of Science:

• Microbiology
• Biotechnology
• Industrial Fermentation

Background:

• Penicillin production is crucial for antibiotic manufacturing.
• Improving microbial strains for higher yields is an ongoing challenge in biotechnology.
• Aspergillus nidulans is a relevant model organism for industrial strain development.

Purpose of the Study:

• To enhance penicillin titre in Aspergillus nidulans strains.
• To evaluate the effectiveness of recurrent mutation and selection for strain improvement.
• To compare two different mutagenesis methods for penicillin yield enhancement.

Main Methods:

• Two selection programs (A and B) were initiated from related Aspergillus nidulans strains.
• Six cycles of mutation and selection were performed.
• Program A used near-ultraviolet light with 8-methoxypsoralen; Program B used ethyl methanesulfonate.
• 100 survivors were assayed for penicillin titre after each cycle, with the top 5 strains selected for the next cycle.

Main Results:

• Both selection programs achieved a near 300% increase in penicillin titre.
• The yield advance was consistent across both mutagenesis strategies.
• The experimental design involving successive cycles of mutagenesis and selection proved effective.

Conclusions:

• Recurrent mutation and selection is a highly effective strategy for strain development in Aspergillus nidulans.
• The chosen mutagenesis and selection methods successfully enhanced penicillin production.
• This study validates a robust experimental design for optimizing microbial yields for industrial applications.