Abstract

• The plant samples were collected from Mogok Township, Mandalay Region. These selected plants were identified as Rosaceae family - Pyrus communis L. (Thit-taw), Eriolobus indica Schnied. (Makhauk), Prunus armeniaca L. (Met-man), Prunus persica (L.) Batsch (Met-mon), and Cydonia oblonga Mill. (Chin-shaw-khar), during June to August, 2017. Isolation of endophytic fungi was done by surface sterilization procedure. The antimicrobial activity of these fungi was performed by agar well diffusion method with six kinds of test organisms. Ten fungal strains showed antimicrobial activity. Among them, three fungal strains exhibited the antimicrobial activity on four test organisms. Especially, SL-26 exhibited the moderate antibacterial activity (22.61 mm) against Escherichia coli at 5 days. Therefore, SL-26 was selected and the fermentation parameters of this fungus were optimized by the proper age and size of inoculum, effect of carbon and nitrogen sources on antibacterial metabolites production against E coli. According to the results, 120 hours age and 25% inoculum size were the most suitable condition for SL-26. In the effect of maximum antibacterial activity on various carbon and nitrogen sources, SL-26 showed the best activity on lactose and asparagine. the comparison of shaking culture and static culture, the antibacterial activity of static culture was more 6.5. Moreover, thirteen kinds of fermentation media (FM) and fermentation period were investigated. The highest antibacterial activity of SL-26 was obtained in FM-11 and the 5th days to be optimum fermentation incubation period. Endophytic fungi are the group of organism with very good potential for application in plant improvement and disease control.