The highest calcite production was observed in KJ-47 (17.6 mg/mL), followed by B-22 (17.2 mg/mL), bacterial mixtures (A3, 15.0 mg/mL), KJ-46 (14.0 mg/mL), and B-21 (12.5 mg/mL). Compared with the single culture, the bacterial mixtures has many advantages because urea hydrolysis rates were higher in it and the pH values of the bacterial mixtures increased more rapidly than those of the different single cultures (data not shown). Urease producing bacteria can promote calcium carbonate precipitation by hydrolyzing urea, and producing ammonium and bicarbonate ions, thereby, increasing the pH and accelerating chemical reactions (Achal and Pan, 2011).