[Search for actinomycetes producing phospholipase C inhibitors]

Area of Science:

• Microbiology
• Biochemistry

Background:

• Phospholipase C enzymes are crucial virulence factors in many pathogens.
• Identifying inhibitors of phospholipase C is important for developing novel antimicrobial strategies.

Purpose of the Study:

• To screen a large collection of actinomycetes for the production of phospholipase C inhibitors.
• To characterize the optimal conditions for inhibitor production by the most active strain.

Main Methods:

• Screening of 2920 actinomycete strains for inhibitory activity against phospholipase C.
• Identification of the most potent strain, Streptomyces saraceticus (strain 0845).
• Optimization of cultural conditions, including carbon/nitrogen sources, aeration, and pH stability.

Main Results:

• 12 actinomycete cultures exhibited inhibitory activity; S. saraceticus strain 0845 showed the highest activity.
• Inhibitor production by S. saraceticus peaked by day three of cultivation.
• Optimal inhibitor synthesis occurred with soybean flour and sucrose as nutrient sources and an oxygen solution rate of 0.84–1.32 g O2/L/h.
• The inhibitor remained active in the cultural broth filtrate for 3 hours at room temperature across a pH range of 4.0–11.5.

Conclusions:

• Streptomyces saraceticus is a promising source of phospholipase C inhibitors.
• The identified inhibitor is stable under various conditions, suggesting potential for therapeutic applications.
• Optimized fermentation conditions can enhance inhibitor yield.