Streptomyces sp. ICC1 and ICC4 were originally isolated from the Iron Curtain Cave which is an
extreme environment featuring low levels of light and nutrients. In previous studies, other
microbes isolated from the Iron Curtain Cave showed biomineralization potential through
microbiologically induced carbonate precipitation (MICP) using urea hydrolysis which has the
potential to be used for biocement production. The objective of this study is to determine the MICP
potential of ICC1 and ICC4 through urease activity and calcium carbonate production as well as
the presence of urease and carbonic anhydrase genes. Streptomyces sp. ICC1 and ICC4 that were
grown on urea agar exhibited a pink colour after one-week incubation at 15°C indicative of active
urease activity. ICC1 and ICC4 showed crystal-like formations when incubated on B4 agar at 15°C
but could not be confirmed to be calcium carbonate. Polymerase chain reaction (PCR) primers
were designed and tested to amplify all ureC gene copies in DNA extracted from ICC1 and ICC4.
Gel electrophoresis and Sanger sequencing results confirmed the successful amplification of all
ureC copies as expected from previous sequencing results from Gosse et al. in 2019. Bioinformatic
analysis revealed that none of the ureC gene copies were associated with a complete seven-gene
operon as seen in most ureolytic bacteria, which suggests the potential for limited urease activity
than initially expected. Four carbonic anhydrase genes were detected in the ICC1 and ICC4
sequencing data suggesting the potential for a synergistic effect with urease enzymes.
