Sulfate reduction bacteria (SRB) is one of the bacteria used in reducing the level of environmental pollution, namely the ability to reduce dissolved sulfate and optimize the acidity (pH) and this shows that the land is an acidity environment. Sulfate-reducing bacteria are obligate anaerobic bacteria that can grow in anoxic environments such as rice fields and swamps. This study aims to determine the characteristics of sulfate-reducing agents in Jejangkit swampland, South Kalimantan, and to test the ability of these bacteria to reduce sulfate metal. Soil samples taken from a depth of 15 cm, 25 cm, 50 cm, and 75 cm were isolated at each to obtain isolates. Bacterial isolates were further characterized based on morphological characteristics (microscopic and macroscopic) as well as biochemical tests including motile test, indole test, and H2S production. This study could grow 3 isolates of sulfate-reducing bacteria (BS 251, BS 252, and BS 501) from Jejangkit swampland, South Kalimantan which was characterized by a change in the color of the medium to black. Based on the study result of the 3 bacterial isolates it was classified as non-obligate anaerobic bacterial another genera of Desulfovibrio with the characteristic of having stamp bacterial cell, motile, no spore, and growing on organic carbon, and having the ability to reduce sulfate. The decreasing of dissolved sulfate level after the test showed that the bacterial isolate could reduce sulfate level compared with control (without isolate and only Postgate medium).

Keyword: sulfate reducing bacteria, isolation, acid sulfate lands