Isolation and Screening of Proteolytic Bacteria from Rice-Fish Farming System Sediments

Activities in the Minapadi fish farming ecosystem are closely related to the role of microorganisms, including degrading bacteria found in sediment. Therefore, in the short term, this research aims to determine the proportion and activity index of proteolytic bacteria isolated from the sediment of the mina rice cultivation system. Research is expected to find the best isolate as a probiotic agent which can be used in fish cultivation in the long run. The method used is observation. Sediment sampling was carried out using a purposive random sampling method in two ponds of the Minapadi fish cultivation system which have different characteristics. Sampling was taken at Block A and Block E, at each location 3 points were taken, namely inlet, middle and outlet. The results of the study showed that the proportion of proteolytic bacteria was found in the sediment in varying proportions in Block A and Block B with respective values, namely inlet (72%; 68%), middle (76%; 72%), and outlet (52%; 48%). Proteolytic activity index with successive values: inlet (0.4-4.0: 0.2-2.5), middle 0.6-6.0: 0.4-4.0 and outlet (0.3-3.8: 0.6-4.0). Five bacterial isolates were found to have the highest proteolytic activity index (>4), namely SAT.2, SAT.7, SAT.12, SAT.11, and SET.10. This research obtained interesting results regarding the activity index and proportion of proteolytic bacteria isolated from rice fish sediments. Most of the proportions of proteolytic bacteria from both blocks showed higher proportions than the general bacteria obtained. Therefore, it can be concluded that bacterial isolates are capable of biodegrading proteins found in organic materials.