Abstract

• Soil samples from three different areas of Laputta Township, Ayeyawady Region were cultured on five kinds of media. A total of 79 bacterial colonies were isolated from these soil samples. The purpose of this study was to screen for antimicrobial activities and fermentation conditions for selected bacterium. In this study, antimicrobial activities of all isolated strains were examined by agar well diffusion assay with seven test organisms. Among them, ten strains namely YN-1, 6, 7, 35, 51, 55, 56, 57, 59, and 63 showed different levels of antimicrobial activities. Especially, YN-51 showed the highest activity on Candida albicans. The fermentation conditions of YN-51 were optimized by the studies of fermentation period, proper size, age, different carbon and nitrogen sources utilization, pH, temperature, static and shaking culture on antimicrobial metabolite production on Candida albicans. In the fermentation period, YN-51 showed the highest activity (22.31 mm) in 3 days followed by (21.82 mm) in 2 days against Candida albicans. In the investigation, YN-51 was found that 15% of size of inoculum and 72 h of age of old culture were suitable conditions. The addition of glucose as a carbon source resulted better growth of YN-51 and the inhibition zone reached 27.07 mm in sucrose. In the nitrogen source, the maximum growth of YN-51 was found in yeast extract and the highest antifungal activity (30.49 mm) was found in beef extract. And then, effects of pH range and temperature were also determined. According to the results, pH 7.5 and temperature 40 °C were found to be the best activities (29.64 mm and 27.29 mm) on Candida albicans respectively. In the comparison between shaking culture and static culture, the antifungal activity reached (25.61 mm) in shaking culture and (21.70 mm) in static culture respectively.