A54145, a new lipopeptide antibiotic complex: discovery, taxonomy, fermentation and HPLC

Area of Science:

• Microbiology
• Biochemistry
• Animal Science

Background:

• A54145 is a novel lipopeptide antibiotic complex with demonstrated efficacy against Gram-positive bacteria.
• This complex also exhibits potential as a growth promotant in broiler chicks.
• Eight distinct factors (A, B, C, D, E, F, A1, B1) constitute the A54145 complex, each sharing similar peptide nuclei.

Purpose of the Study:

• To isolate and characterize the individual components of the A54145 antibiotic complex.
• To identify the producing microorganism and optimize fermentation conditions for enhanced antibiotic production.
• To develop an analytical method for quantifying the A54145 factors.

Main Methods:

• Taxonomic studies to identify the producing microorganism.
• Fermentation optimization in stirred bioreactors using a soybean flour-molasses medium with continuous glucose feed.
• Selection of hyper-productive Streptomyces fradiae mutants.
• Development of an analytical High-Performance Liquid Chromatography (HPLC) system for factor identification and quantification.

Main Results:

• The producing microorganism was identified as a strain of Streptomyces fradiae.
• Optimized fermentation conditions and mutant selection led to a significant increase in antibiotic yields, from <50 µg/ml to >1 mg/ml.
• An analytical HPLC system was successfully established for the identification and quantitation of the eight A54145 factors.
• The lipopeptide factors were characterized by their peptide nuclei and acylated side chains (2-decanoyl, n-decanoyl, or undecanoyl).

Conclusions:

• Streptomyces fradiae produces the lipopeptide antibiotic complex A54145.
• Significant improvements in antibiotic yield were achieved through fermentation optimization and strain improvement.
• The developed HPLC method enables accurate analysis of the A54145 complex components.
• A54145 shows promise as a novel antibacterial agent and a broiler growth promotant.