Ureolytic bacteria isolated from Sarawak limestone caves show high urease enzyme activity comparable to that of Sporosarcina pasteurii (DSM 33)

ABSTRACT

Aims: Microbial induced calcite precipitation (MICP) is a natural occurring biological process that employs the usage of ureolytic bacteria for a wide range of applications such as improving the mechanical properties of soils. The aim of this study was to isolate and identify local urease-producing bacteria from the limestone caves of Sarawak and characterise their specific urease activities. Methodology and results: Enrichment culture technique was used to isolate urease-producing bacteria. These local isolates were identified using phenotypic and molecular characterisation. Conductivity method and biomass (OD600) measurements were conducted to analyze and determine the specific urease activities of the local isolates. 16S rRNA gene sequence analysis identified the bacterial isolates as Sporosarcina pasteurii, Sporosarcina luteola and Bacillus lentus. Conclusion, significance and impact of study This is the first study reporting the isolation and identification of urease-producing bacteria from Fairy and Wind Caves situated in Bau, Sarawak, Malaysia. The findings in this study suggest the bacterial isolates are capable of inducing calcite precipitation and serve as alternative microbial ureolytic agents.