Engineering the biosynthesis of natural lipopeptide octapeptins in Paenibacillus elgii 219 to combat multidrug-resistant

The escalating global antimicrobial resistance crisis underscores the urgent need for novel antibiotics. Here, Paenibacillus elgii 219 is identified as an efficient producer of octapeptins (B2, B3, A1 and B1) by nuclear magnetic resonance and tandem mass spectrometry. These octapeptins exhibited broad-spectrum antibacterial activity, high stability under extreme pH, temperature, and enzymatic conditions, and without cytotoxicity. These promising bioactivity and stability profiles, underscore the need to optimize methods to increase octapeptins yields to unlock their application prospects. Initial fermentation optimization markedly augmented the total octapeptins yield by 32-fold, achieving 1.0 g/L; Atmospheric and room temperature plasma mutagenesis and chromogenic screening picked a superior mutant with a 75 % higher octapeptins titer (1.7 g/L), as confirmed by transcriptomic analysis. Targeted knockout of glycosyltransferases GTp4383 and GTp5312 reduced broth viscosity and increased the total octapeptins titer to 2.3 g/L, and further scaled up to 3.94 g/L in fed-batch fermentation. This integrated approach establishes a scalable platform for high-yield octapeptins production, highlighting its potential as a next-generation anti-resistance agent. • Discovery and Characterization of Novel Octapeptins with Excellent Antimicrobial Properties and Stability. • Systematic Fermentation Optimization Boosts Octapeptin Yield by 32-Fold. • Development of a High-Throughput Screening Method and Isolation of a High-Yield Mutant via ARTP Mutagenesis. • Targeted Genetic Engineering Reduces Broth Viscosity and Further Enhances Production.