This study determined the optimal nutrient and environmental conditions to produce antimicrobial and cytotoxic agents by Streptomyces cavourensis YBQ59 during the fermentation process. The bioactivities of eluted fractions based gradient solvents via chromatography column were also evaluated. S. cavourensis YBQ59 exhibited strong antimicrobial activities against methicillin-resistant Staphylococcus epidermidis ATCC 35984 (MRSE) and Salmonella Typhimurium ATCC 14028 under fermentation conditions as follows: MT6 medium with soluble starch and soybean powder as carbon and nitrogen sources, respectively, temperature 30 oC, initial pH , 20 % DO concentration and with 5% initial seed culture. The kinetic of fermentation showed that the antimicrobial activities were highest at between 72 h and 78 h. The fraction 25/1 D-M (dichloromethane –methanol) exhibited the highest antimicrobial effect against methicillin-resistant Staphylococcus aureus ATCC 33591 and MRSE with minimum inhibitory concentrations of µg/ml and µg/ml, respectively. The fraction 10/1 D-M had strong cytotoxic effects towards multidrug-resistant A459 and H1299 lung carcinoma cell lines with the cell viability of % and %, respectively. In conclusion, S. cavourensis YBQ59 would be a potential producer of valuable bioactive compounds that may have a board application in pharmaceutical industry and agriculture (biocontrol, livestock, food safety and quality management). | Optimal fermentation conditions for antibiotic production by endophytic Streptomyces cavourensis YBQ59 isolated from Cinnamomum cassia Presl
