Optimization of medium composition for antibacterial metabolite production from Streptomyces sp.

Abstract

Objectives: This paper aimed to optimize some essential nutritional components (carbon, nitrogen, and phosphate) of fermentation medium necessary for the production of antibacterial metabolites from Streptomyces sp. Materials and Methods: Streptomyces sp. LH9 previously isolated from desert soil in Karbala Province, Iraq. This strain produced antibiotic against 4 pathogenic bacteria, including Escherichia coli, Staphylococcus aureus, Streptococcus agalagtiae, and Pseudomonas aeruginosa. For optimizing, the essential nutritional requirements such as carbon, nitrogen, and phosphate in fermentation media different concentrations of these sources were used to improve the antibacterial metabolite production. Results: All the studied nutritional parameters were had impacts on the antibacterial metabolite production from Streptomyces sp. LH9. The actinobacterial strain produced a highest antibiotic metabolites when was grown in the fermentation medium supplemented with 2% dextrose (as a sole carbon source), 0.05% peptone (as a sole nitrogen source), and 0.05% K2HPO4 at pH 7 and incubated under optimal conditions; at 30°C with 250 rpm (revolutions/min) agitation for 7 days. Conclusion: Streptomyces sp. LH9 was a good producer for antibacterial against Gram-positive and Gram-negative bacteria, which required simple nutritional supplements in the fermentation medium. Furthermore, could be utilized the industrial waste for improving the production in the most economic manner.