Β-lactamase inhibitor antibiotic is highly required to prevent the increasing of bacterial resistance towards β lactam antibiotics. This study was aimed to isolate and characterize of bacteria producing TEM-1 β lactamase inhibitor antibiotic. Sample of study was Black Water Ecosystem, selected from 65 areas in Central Kalimantan. An agar diffusion method was applied to select the isolate, based on its potential to inhibit the growth of Escherichia coli 35218 that produce TEM-1 β lactamase enzyme. Based on the large of inhibitor zone, one of Gram negative bacteria selected as a potential isolate. It can inhibit E. coli 35218 growth in average 14 mm. This isolate with ICBB 1171 coding is a single cell, rod shaped arranged in pairs or chain, in length between 4.0 µm to 4.2 µm, and diameter is average 1.7 µm. The colony form is circular, with cream to pink colors. This isolate can be mixed with glucose, sucrose and mannitol as a source of carbon. Its optimal growth is on 300 °C and pH 7.0. The exponential phase is achieved for 32 hours.