Precipitation and characterization of CaCO3 of Bacillus amyloliquefaciens U17 strain producing urease and carbonic anhydrase

Abstract

In the present study, the properties of calcium carbonate mineralization and urease and carbonic anhydrase activities ofBacillus amyloliquefaciens U17 isolated from calcareous soil of Denizli (Turkey) were analyzed. CaCO3 was produced in all growthphases. Strain U17 showed 0.615 ± 0.092 µmol/min/mg urease enzyme activity in calcium mineralization medium and 1.315 ± 0.021µmol/min/mg urease enzyme activity in Luria-Bertani medium supplemented with urea, whereas it showed 36.03 ± 5.48 nmol/min/mg carbonic anhydrase enzyme activity in CaCO3 precipitation medium and 28.82 ± 3.31 nmol/min/mg carbonic anhydrase enzymeactivity in Luria-Bertani medium supplemented with urea. The urease B protein expression level of strain U17 was detected by westernblotting for the first time. The produced CaCO3 crystals were analyzed by X-ray diffraction, X-ray fluorescence, confocal RAMANspectrophotometer, scanning electron microscopy, and electron probe microanalyzer for the evaluation of their morphological andelemental properties. Rhombohedral vaterite and layered calcite crystals were clearly detected and verified by mineralogical analyses.All these results showed that strain U17 can be used in many engineering and geological applications due to its CaCO3 precipitationability.