Judul: Eksplorasi Spasial Karang Lunak Kaitannya dengan Senyawa Bioaktif Bakteri Simbion.
Abstrak: In ecology, soft and hard corals have the same function in the waters. The distribution of soft corals is strongly influenced by the characteristics of the aquatic environment. Soft corals had been knows contain of bioactive compounds that can be used as a marine natural product, but naturally theses resource are limited and very difficult to cultivated. Therefore, the isolation of bacterial symbiont on soft coral is one of alternatives in an effort to utilize these resources in sustainability. This study had four main objectives that include the following: (1) to determine the differences of the soft corals between sheltered and exposed area in Pongok Island, Soulth of Bangka and Tegal Island in Lampung Bay, Indonesia; (2) to find of the soft corals inhibition potential for antibacterial activity; (3) to measure the antibacterial activity level and minimum inhibitory concentration of bioactive compounds in the soft coral S. flexibilis and S. polydactyla species; (4) to find the isolation of bacterial symbionts from soft coral S. flexibilis and S. polydactyla species that the potential to producted bioactive compound. The results found eigtht types of soft corals classified in four genera (Lobophytum, Nephthea, Sarcophyton and Sinularia) were found in both sites, six species were identified in the waters of South Bangka (at 9 meters depth) and two species (at 3 meters depth). In Tegal Island waters (closed waters), only 2 species from the genus Sinularia were recorded (at 2-5m depth). There were 2 stations at Pongok Island namely, PGK1 and PGK2, while in Tegal Island, there were 4 stations namely TGL1, TGL2, TGL3 dan TGL4. Principal component analyses showed that both waters can be classified based on their physical-chemical characteristic, which were depth, currents, phosphate and turbidity waters. Discriminant function were showed in phosphate variable. While the similarity analysis showed that both waters had very strong similarity of about 79%. In sampling treatment, the biomass among wet and dry samples varied. The highest shrinkage due to drying was found in Nephthea, followed by Lobophytum and Sarcophyton, while the lowest was found in the genus of Sinularia. Extracted from 12 samples of soft coral, the lowest extract weight was found in the semipolar solvent (EtOAc), while the extract weight of n-Hex and MeOH was vary. Inhibition power from all extract samples were found on soft coral extract in the EtOAc and MeOH solvents. The highest value of inhibition power was found in soft coral of Sinularia polydactyla and S. flexibilis within strong catogery. Principal component analysis showed there were corelations between the the environment characteristics with the bioactive compounds inhibition of soft corals, that the identifier parameters include; depth, currents, phosphate and turbidity waters. Discriminant function were showed in depth variable. Extracts weight of both species S. flexibilis (SFTLS4) and S. polydactyla (SPTLS2) found the same relatively, except extract in n-Hexane (n-Hex) solvent from SFTLS4 samples that higher compered to extract weigth in other solvents. vii Antibacterial activites of both spesies showed only on extract in ethyl acetate (EtOAc), within strong category. For purification were obtained eigth fractions (F1-F8) for SFTLS4 extractions and six fractions (F1-F6)
Keyword: antibacterial activity, bacterial symbiont, bioactive compound, sinularia, soft coral