ABSTRACT Ureolytic bacteria are a group of bacteria that can produce urease enzymes to hydrolyze urea. Ureolytic bacteria are able to produce calcite (CaCO3) through the precipitation process. The purpose of this study was to determine the toxicity of five isolates of SP. 32, SP. 34, SP. 48, SP. 83, and SP. 84 and the ability of the five isolates to produce calcite. Bacterial bioassay was carr…