Characterization of Urease From Soil Bacterial Isolates for Concrete Enhancement.

Abstract

Ureases are a group of enzymes that hydrolyse urea producing carbon dioxide and ammonia. This work examined the characterization of urease from soil bacterial isolates for concrete enhancement. Soil samples were collected from concrete construction sites within Minna, Nigeria and transported to the laboratory of the Department of Microbiology, Federal University of Technology, Minna. To screen for the presence of urease producing bacteria, the soil sample was diluted ten-fold and cultured on urease selective media. The bacterium with highest urease production potential identified as Bacillus sp. was used for its large scale production. The rate of urease production was determined by spectrophotometry. The optimum temperature, pH, and incubation period for urease production were determined. The medium was centrifuged at 6000 rpm for 30 minutes and sterilised by filtration. The cell free supernatant containing crude enzyme was mixed with different ratios of cement for the production of concrete. A control was set up, without urease. Compressive strength test and spilt tensile test were determined in conformity with building specifications standards. The result obtained showed that urease produced by Bacillus was able to enhance the concretes and can be used for concrete enhancement.