Acid-ProducingEnterococcusSp.fromGratiLake’sEndemicGobiopterus Sp. A Novel Probiotic Candidate

Gobiopterus sp., inhabiting the extreme volcanic lake Ranu Grati, offers a potential source of unique lactic acid bacteria (LAB) with probiotic properties. This study aimed to isolate, characterize, and evaluate LAB from Gobiopterus sp. digestive tract as potential probiotic candidates. Isolates underwent tests for Gram staining, gastric juice and bile salt tolerance, antibacterial activity, extracellular enzyme production, and hydrophobicity. A total of 16 bacterial isolates were obtained, of which 9 were Gram-positive and catalase-negative. These isolates exhibited tolerance to acidic pH conditions and bile salts. Antibacterial activity varied among the isolates, with some showing significant inhibition against common fish pathogens. Enzyme activity assays revealed the production of protease and cellulase enzymes, aiding in nutrient digestion. DNA sequencing identified four isolates as belonging to the genus Enterococcus, a well-established probiotic genus. These findings suggest that Enterococcus spp., identified as a lactic acid bacteria isolated from Gobiopterus sp., is a promising candidate for use as a probiotic.