THE EFFECT OF MEDIA AND FERMENTATION CONDITION TOWARD ANTIBACTERIAL ACTIVITIES OF BACILLUS SP. DA11 ASSOCIATED WITH SARCOPHYTON SP.

The emergence of antibiotic-multidrug resistant microorganisms is an essential issue in the health sector. Consequently, the exploration of new antimicrobial compounds from many promising resources is urgently required. Soft coral-associated bacteria are potential as antimicrobial compound producers. This study aims to get the best medium and fermentation conditions in the production of secondary metabolites having antibacterial activities and to identify antibacterial agents from a bacterium associated with soft coral. A soft coral sample was collected from Randayan Island, Indonesia, and was identified morphologically as Sarcophyton sp. One of the bacteria isolated from the Sarcophyton sp. showed antibacterial activities and identified as Bacillus sp. based on Bergey’s Manual of Determinative Bacteriology. The best antimicrobial activities of Bacillus sp. DA11 were carried out on medium 1/10 Zobell supplemented with 1% of glucose (1/10ZG) which were able to against all of the test bacteria except on a test fungus, C. albicans. The extract was prepared on medium 1/10ZG with liquid state fermentation without shaking showed the best condition to produce secondary metabolites having antibacterial activities. The extract showed weak antibacterial activities based on minimum inhibitory concentrations (MICs) which were around 150-300 µg/disc for A. hydrophila; Bacillus sp., C.  freundii, Salmonella sp., P. aeruginosa, S. aureus, E. coli, V. cholerae, V. vara, B. subtilis. The results of phytochemical analysis and thin layer chromatography (TLC)-bioautography showed that the secondary metabolite having antibacterial activities contained in the extract was a terpenoid.