Objective: Effect of various culture conditions on the morphology, amount and carbonic anhydrase (CA) activity of Bacillus mucilaginosus were examined, as well as the effect on calcium carbonate crystal forming, shape and amount.
Methods: The strain was inoculated in N-free or N-containing medium, and the bacterial morphology, number and CA activity were compared under different culture conditions. By collecting different cultures and adding them to the system of calcium carbonate crystallization we studied the relationship between the bacteria and the formation of calcium carbonate crystals.
Results: A small number of cell, capsular hypertrophy, lower CA activity in bacterial culture were obtained under N-free culture condition. In contrast, more biomass quantity, thin capsule, and high CA activity were got in the nitrogen-containing culture. In the calcium carbonate crystal system, adding N-free culture of bacteria produced a smooth surface of calcium carbonate crystals, larger volume but small density, the addition N-containing culture of bacteria formed rough surface, bigger density but smaller volume of calcium carbonate crystals.
Conclusion: Different culture conditions can cause significant differences in bacterial amounts, capsular thickness and CA activity, and then influence the crystal growth and form of calcium carbonate.