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Abstract
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Biomineralization is a process by which living
organisms produce minerals. The extracellular production
of these biominerals by microbes has potential for various
bioengineering applications. For example, crack remediation
and improvement of durability of concrete is an
important goal for engineers and biomineral-producing
microbes could be a useful tool in achieving this goal. Here
we report the isolation, biochemical characterization and
molecular identification of Pseudomonas azotoformans, a
microbe that produces calcite and which potentially be
used to repair cracks in concrete structures. Initially, 38
bacterial isolates were isolated from soil and cements. As a
first test, the isolates were screened using a urease assay
followed by biochemical tests for the rate of urea hydrolysis,
calcite production and the insolubility of calcite.
Molecular amplification and sequencing of a 16S rRNA
fragment of selected isolates permitted us to identify P.
azotoformans as a good candidate for preparation of
biotechnological concrete. This species was isolated from
soil and the results show that among the tested isolates it
had the highest rate of urea hydrolysis, produced the
highest amount of calcite, which, furthermore was the most
adhesive and insoluble. This species is thus of interest as an
agent with the potential ability to repair cracks in concrete.
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