Isolation, characterization and optimization of calcite producing bacteria / Maizatul Akmam Mohd Azmi

Concrete had always been the choices in constructing the building and houses
because of its low price and abundance in nature. However the crack problem usually
happen to old building and sometimes it had been cause by the carelessness of the
builders in mixing the mixture during construction works. The calcite producing
bacteria with biomineralization activity could possibly is the solution to the problem
and help in enhancing the concrete properties. Thus the objectives are to isolate,
screen, characterize the calcite producing bacterium and determine the effect of initial
inoculum on calcite precipitation. Pure culture bacteria are obtained with series
dilution of samples and characterize through colony, cell observation and biochemical
test. Calcium carbonate precipitation medium (CCP) was used to screen and evaluate
the ability of the selected bacteria to produce calcite. There are six different isolates
namely as SI, S2, ST2, ST3, STS and STSL. All the isolates are gram positive rods
bacteria except for S2 gram negative rods bacteria. SI, ST2, ST3 and STS were
bacteria with capsule. All bacteria are aerobic and show urealytic activity except for
STSL. S1, ST2, ST3 and STS are bacteria that produce clear zone solubilisation on
CCP medium. The high concentration of the initial inoculum was able to produce
high mass weight of the calcite. Among those 4 bacteria, SI is the most prominent
calcite producing bacteria.