| Xestospongia sp. is one of marine sponges that lives around sands, rocks, and dead corals. It is widely distributed in the sea of Indonesia. Recent study showed that Xestospongia sp. was able to produce alkaloid compounds such as Renieramycin which has an anticancer activity. This metabolite compound might be produced due to the presence of associated bacteria in the sponge. Analysis of bacterial community associated with Xestospongia sp. was done with Terminal Restriction Fragment Length Polymorphism (T-RFLP) method. Analysis of TRF patterns showed that the bacterial communities on Doo (Rote Island) and Melinjo Islands (Thousand Island) were dominated by members of Actinobacteria, Bacilli, Bacteroidetes, Chloroflexi, Clostridia, d-proteobacteria, ?-proteobacteria, and Flavobacteria. A total of 12 classes of microorganism were identified in Doo Island and 14 classes of microorganism were identified in Melinjo Island with the similarity of 55.38%. According to the calculation of Shannon-Weiner index, Simpson's index, and Evenness, the microorganism in Doo Island are more highly distributed and diversed than Melinjo Island. A higher contamination level of phosphate and water flow in Doo Island might cause the extinction of several major classes of sponge associated bacteria and a reduction of bacterial number in each class. The presence of Proteobacteria and Actinobacteria played an important role for Xestospongia sp. to produce metabolite compounds. |