OPTIMAL FERMENTATION CONDITIONS FOR ANTIBIOTIC PRODUCTION BY ENDOPHYTIC Streptomyces cavourensis YBQ59 ISOLATED FROM Cinnamomum cassia Presl

Abstract

This study determined the optimal nutrient and environmental conditions for the production of antimicrobial and cytotoxic agents by Streptomyces cavourensis YBQ59 during the fermentation process. The antimicrobial and cytotoxic activities of eluted fractions based gradient solvents via silica gel column of chromatograph were also evaluated. S. cavourensis YBQ59 exhibited strong, board-spectrum antimicrobial activities under fermentation conditions as follows: MT6 medium with soluble starch and soybean powder as carbon and nitrogen sources, respectively, temperature 30oC, initial pH 7.0, 20% DO concentration and with 5% initial seed culture. The kinetic of fermentation showed that the antimicrobial and cytotoxic activities were highest at between 72h and 78h. The fraction 25/1 D-M (dichloromethane –methanol) exhibited the highest antimicrobial effect against methicillin-resistant Staphylococcus aureus ATCC 33591 and methicillin-resistant Staphylococcus epidermidis ATCC 35984 with minimum inhibitory concentrations of 9.4 µg/ml and 6.4 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 11.3% and 12.4%, 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)