3.1 Bacterial preparation and application The cultures were suitably incubated in an orbital incubator at 37° C at a rate of S. pasteurii 200 rpm. The cultures were then measured at OD600 to see if the cell density is within the desired range (Approx. 0.9-3). A higher OD will provide more nucleation sites for calcite formation. Once the culture was prepared a100ml aliquot containing the bacterial cultures was added to a 900ml Duran container of nutrient broth with 50ml CaCl2 (calcium chloride) at a concentration of 1g/ml. Immediately after mixing the solution, it was applied to the 3 beam sections and cubes. 15ml of solution per cube was applied followed by 1.5ml of urea to catalyse the reaction and help support the bacteria’s hydrolysis, leading to a higher calcite yield. 4.0 Results Oxygen Carbon Calcium The bacterial residue was (%) (%) (%) examined at the surface Background 58.0 17.5 24.5 (foreground) and at the intersection between the Foreground 60.6 13.4 26.0 calcite and the concrete (background), using an Energy Dispersive Spectroscopy (EDS) image analysis technique and the chemical component parts are displayed in Table 3 and Figure 6. Table 3 Chemical component parts of calcite deposit – Figure 6 - Energy Dispersive Spectroscopy (EDS) image The Energy Dispersive Spectroscopy (EDS) results were tested alongside a MOH’s hardness test and hydrochloric acid test which showed the calcite formation was within normal
3.1 Bacterial preparation and application The S. pasteurii cultures were suitably incubated in an orbital incubator at 37° C at a rate of 200 rpm. The cultures were then measured at OD600 to see if the cell density is within the desired range (Approx. 0.9-3). A higher OD will provide more nucleation sites for calcite formation. Once the culture was prepared a100ml aliquot containing the bacterial cultures was added to a 900ml Duran container of nutrient broth with 50ml CaCl2 (calcium chloride) at a concentration of 1g/ml. Immediately after mixing the solution, it was applied to the 3 beam sections and cubes. 15ml of solution per cube was applied followed by 1.5ml of urea to catalyse the reaction and help support the bacteria’s hydrolysis, leading to a higher calcite yield. 4.0 Results The bacterial residue was examined at the surface (foreground) and at the intersection between the calcite and the concrete (background), using an Energy Dispersive Spectroscopy (EDS) image analysis technique and the chemical component parts are displayed in Table 3 and Figure 6. Oxygen (%) Carbon (%) Calcium (%) Background 58.0 17.5 24.5 Foreground 60.6 13.4 26.0 Table 3 – Chemical component parts of calcite deposit Figure 6 - Energy Dispersive Spectroscopy (EDS) image The Energy Dispersive Spectroscopy (EDS) results were tested alongside a MOH’s hardness test and hydrochloric acid test which showed the calcite formation was within normal
DundeeConference%20Bacterial%20Concrete%20paper.docx