Engineering Streptomyces Albulus for Efficient ε-Poly-l-lysine Production.

Area of Science:

• Microbiology
• Biotechnology
• Biochemistry

Background:

• ε-Poly-l-lysine (ε-PL) is a natural polymer with antimicrobial and superabsorbent properties, valuable for food preservation and biomaterials.
• Current commercial production of ε-PL faces challenges due to high costs and low yields.

Purpose of the Study:

• To develop an efficient strategy for enhancing ε-PL production in *Streptomyces albulus*.
• To overcome the limitations of high production costs and low yields in ε-PL manufacturing.

Main Methods:

• A *Streptomyces albulus* mutant strain (FMME-545RX-S) was created using ARTP mutagenesis and ribosomal engineering.
• Fed-batch fermentation, comparative transcriptomic analysis, gene coexpression (*gltA*, *nuoF*), and fermentation optimization were employed.
• Strain ZW2 was developed and optimized for maximal ε-PL production.

Main Results:

• The engineered mutant FMME-545RX-S achieved an ε-PL titer of 34.5 g/L, a 50% increase over the parent strain.
• Coexpression of *gltA* and *nuoF* increased the ε-PL titer to 40.5 g/L.
• The optimized strain ZW2 produced 60.1 g/L ε-PL in a 5 L fermenter.

Conclusions:

• The study presents an effective strategy combining mutagenesis, genetic engineering, and fermentation optimization to significantly boost ε-PL production.
• The developed methods offer a promising pathway for cost-effective and high-yield ε-PL manufacturing.
• The enhanced *S. albulus* strains and optimized conditions pave the way for industrial-scale ε-PL production.