*3.6.1.2 Precipitation characterization study of CaCO3 in microorganism solution*

In this way, the ability of this bacterium to precipitate salt has been qualitatively studied. **Table 9** shows the composition of E-coli solutions with different concentrations of CaCl2.2H2O and urea.

For the preparation of the above solutions, a quantity of microorganism solution has been isolated, and the corresponding amount of CaCl2 and urea every time. These solutions were incubated at 37°C and 100 rpm. The solution of the microorganism that contained the most amount of CaCl2.2Η2Ο and urea showed the greatest turbidity of the other solutions with apparent precipitation of CaCO3. After 72 h in these conditions, the solutions were removed and compared. Below are


### **Table 7.**

*Quantities of materials used for the kinetic precipitation study CaCO3 from microorganism solution to LB nutrient material.*

*Self-Healing of Concrete through Ceramic Nanocontainers Loaded with Corrosion Inhibitors… DOI: http://dx.doi.org/10.5772/intechopen.93514*


**Table 8.**

*Quantities of materials used for the kinetic precipitation study of CaCO3 from microorganism solution to a nutrient agar medium in a petri dish.*


**Table 9.**

*Composition of E-coli solutions with different concentrations of CaCl2.2H2O and urea.*

the photos of the nutrient solution, the solution of the bacterium after incubation, and the 5th solution. As shown above, during the development of the microorganism *E-coli,* a comparative study is carried out, and there is a marked change in the turbidity of the solutions. The change in clarity between the nutrient solution, LB and the solution after the development of the microorganism, certifies that the microorganism has been properly incubated to study any of its metabolic processes. **Figure 13** C has a marked turbidity in the solution of the microorganism that contained the most CaCl2.2Η2Ο and urea, in relation to the incubation solution of the microorganism. The sediment submerged can be attributed to the creation of CaCO3 from the *E-coli*. The visual characterization of calcium carbonate precipitation shows that the *E-coli* through the ureolytic breakdown sink CaCO3. Two types of bacteria have been studied in this paper, *E-coli* and *St. aureus*, for their ability to break down urea and precipitate CaCO3 in an environment rich in Ca2+. Through the quality tests carried out, it was observed that both bacteria precipitate the desired mineral. Further characterization was carried out with the *St. aureus,* where a kinetic study was carried out on the existence of CaCO3, in two different nutrient environments of the microorganism. In both cases, precipitation of the mineral. These bacteria in force can be used in the phenomenon of self-feeding of cement, since it is evident that they can precipitate CaCO3 under certain circumstances.
