Symbiotic microbes from various seaweeds with antimicrobial and fermentative properties

Symbiotic organisms are viable sources of bioactive compounds. This study aims to determine the microbial species from some seaweeds through molecular identification. The samples were collected from the waters of Bunaken, Northern Sulawesi using purposive sampling method. The spread method was used in microbial isolation and purification, whereas overlay and agar diffusion methods were used in the antimicrobial activity test. Oxidative fermentative (OF) test was used to determine glucose metabolism. The microbes were identified using molecular identification method (PCR 16S rDNA). The isolation process found 88 symbiotic microbes from 3 seaweed species (Eucheuma spinosum, Gracilaria gracilis, and Glacilaria verrucosa). 16 isolates showed antimicrobial activity, whereas 9 isolates showed both fermentative properties and antimicrobial activity. The antimicrobial sensitivity test found 4 microbial isolates from E. spinosum with active antimicrobial activity against the pathogenic microbes Escherichia coli and Staphylococcus aureus, while the 5 remaining isolates from G. verrucosa and G. gracilis only showed active antimicrobial activity against the pathogenic microbe S. aureus. Molecular identification of the 4 isolates with both antimicrobial activity and fermentative properties from isolate ES 2.2 showed 98% homology with Vibrio parahaemolyticus, isolate GM 4.4 showed 99% homology with Vibrio jascida, 2 strains of Vibrio hyugaensis, and 2 strains of Vibrio alginolyticus.