Optimization Of Culture Medium And Extraction Conditions For Antimicrobial Activity Of Streptomyces C22 Isolated From Con Dao Island

Abstract

Streptomyces are the producers of bioactive compounds for the biotechnology industry. Streptomyces C22 isolated from Con Dao were preliminarily screened in a previous study for antimicrobial and antifungal activities (Thuong, 2019). Attempts were made to optimize the media and solvent extraction conditions to increase antimicrobial activities using the disk diffusion method. Different concentration of NaCl (0.5%, 1% and 1.5%) and Casamino acid (0%, 0.01% and 0.02%) were added to culture media with basic components from ISP4. Antimicrobial potential reached the maximum level at the time point of 120-hour incubation in the medium containing 1% of NaCl and 0.01% of Casamino acid. At this condition, Streptomyces C22 was able to enhance the inhibition zones of Staphylococcus aureus from 18 mm to 33.7 mm after 120 hours of incubation. Additionally, ethyl acetate was illustrated as the most suitable solvent for the extraction of secondary metabolites in this research.