It was discovered that Microbacterium sp. GM-1 resisted high concentrations of urea up to 60 g/L. In order to optimize the calcification process of Microbacterium sp. GM-1, the concentrations of Ni2+ and urea, pH value, and culturetime were analyzed through orthogonal tests. The favored calcite precipitation culture conditions were as follows the concentration of Ni2+ and urea were 50 µM and 60 g/L, respectively, pH of 10, and culturetime of 96 h. Using X-ray diffractionanalysis, the calcium carbonate polymorphs produced by Microbacterium sp. GM-1 were proven to be mainly calcite.
Conclusions:
The results of this research provide evidence that Microbacterium sp. GM-1 can biologically induce calcification and suggest that strain GM-1 may play a potential role in the synthesis of new biominerals and in bioremediation or biorecovery.